2003 Aziscohos Lake Common Loon Population Survey and Management Report (REPORT BRI – 2003-03) (FERC Project No. 4026)

Submitted to: William Hanson FPL Energy Maine Hydro 150 Main St. Lewiston, Maine 04240 Submitted by: Lucas Savoy, Chris DeSorbo, Theresa Daigle and David Evers BioDiversity Research Institute 19 Flaggy Meadow Road Gorham, ME 04038 [email protected] Rough draft submitted: March 17, 2004 Final draft submitted: January 4, 2007

2003 Aziscohos Lake Common Loon Survey and Management Report EXECUTIVE SUMMARY..................................................................................................................................................2 INTRODUCTION................................................................................................................................................................2 About the Study Site.............................................................................................................................................................2 History And Purpose Of Study.............................................................................................................................................2 OBJECTIVES ......................................................................................................................................................................3 METHODS ...........................................................................................................................................................................4 1. POPULATION AND NESTING SURVEYS ..................................................................................................................4 2. LOON MANAGEMENT TOOLS: RAFTS, AVIAN GUARDS AND SIGNS..............................................................4 Raft Implementation......................................................................................................................................................4 Avian Guards ................................................................................................................................................................5 Signs..............................................................................................................................................................................5 3. ABANDONED EGG COLLECTION..............................................................................................................................5 Collection of Eggs.........................................................................................................................................................5 Egg Sample Analysis ....................................................................................................................................................6 4. SURVEYING FOR MARKED INDIVIDUALS .............................................................................................................6 5. EVALUATION OF HABITAT QUALITY.....................................................................................................................6 RESULTS AND DISCUSSION...........................................................................................................................................7 1. POPULATION AND NESTING SURVEYS: PRODUCTIVITY SUMMARY 2003 ....................................................7 Overall Lake-wide Productivity Summary....................................................................................................................7 Nest Failures..................................................................................................................................................................7 Renests ..........................................................................................................................................................................8 Qualitative Territory Summary (Aziscohos Lake, 2003) ..............................................................................................8 2. LOON MANAGEMENT TOOLS: RAFTS, AVIAN GUARDS...................................................................................11 Raft Implementation....................................................................................................................................................11 Avian Guards ..............................................................................................................................................................11 Raft Vs. Natural Nest Site Summary...........................................................................................................................12 Raft vs. Natural Nest Site Productivity .......................................................................................................................12 Rafts vs. Natural Nest Sites: Failures ..........................................................................................................................13 Rafts vs. Natural Nest Sites: Renests ..........................................................................................................................13 3. ABANDONED EGG COLLECTION AND ANALYSIS .............................................................................................14 4. EVALUATION OF HABITAT QUALITY...................................................................................................................14 5. LATE-SEASON CHICK MONITORING AND OVERALL CHICK SURVIVAL .....................................................16 6. PRODUCTIVITY SUMMARY (2003) COMPARISON TO LONG TERM MEANS (1987-2002) ..............................17 7. YEAR 2003 RECOMMENDATIONS...........................................................................................................................18 LITERATURE CITED......................................................................................................................................................19

1

2003 Aziscohos Lake Common Loon Survey and Management Report SUMMARY OF TABLES Table 1 2 3 4 5

Title Lake Survey Visit Record for 2002 on Aziscohos Lake, Maine Common Loon Productivity and Nesting Summary (2002) Common Loon Comparative Nesting Summary: Rafts vs. Natural Nests (2002) Habitat Quality Ranking within loon territories using long-term reproductive means, Aziscohos Lake (1987-2002) Common Loon Productivity on Aziscohos Lake from 1987 –2002, with comparisons to calculated long-term means

Page 4 7 14 16 20

SUMMARY OF FIGURES Figure 1 2 3 4

Title Rangeley Lakes Region Study Area Distribution of Common Loon Territories on Aziscohos Lake, 2002 Daily Reservoir Surface Elevations for Aziscohos Lake Territorial Habitat Quality Map

Page 23 24 25 26

SUMMARY OF APPENDICES Appdx. 1 2 3 4

Title Territory-Specific Productivity Summary Nesting Summary: Raft vs. Natural Sites Nesting Activity Dates in Relation to Water Level Definition of Terms

Page 27 28 29 30

SUMMARY OF MAPS (Pages 34-43) Map 1. Little Magalloway, Sunday Pond and Bosebuck territory nest site locations, 2003. Map 2. Twin Brook territory and nest dish (not a nesting pair) location, 2003. Map 3. Camo Camp territory nest site location, 2003. Map 4: Hurricane and Raven territories nest site locations, 2003. Map 5: Hammel Brook territories nest site locations, 2003. Map 6: Buck Mountain territory nest site location, 2005. Map 7: Meadow Brook territory nest site location, 2003. Map 8: Cold Brook territory nest site location, 2003. Map 9: Emery’s Misery and Grove territory nest site locations, 2003. Map 10: Beaver Brook territory and nest site, 2003.

2

2003 Aziscohos Lake Common Loon Survey and Management Report

EXECUTIVE SUMMARY The surface elevation of Aziscohos Lake is controlled by the Aziscohos os Dam, which is licensed as Federal Energy Regulatory Commission (FERC) Project No. 4026-002ME. Article 33 under this license requires surveys of Aziscohos Lake’s loon population in order to evaluate the necessity and feasibility of the use of artificial nesting islands. BioDiversity Research Institute conducts surveys and oversees management of loons on Aziscohos Lake. The number of territorial pairs increased from 19 pairs in 2002 to a high of 21 pairs in 2003. Of these pairs, 13 nested with 13 nest attempts recorded lake-wide. There were no renests. We deployed 17 rafts, 9 (69%) of which were used for nesting by loons. Those 9 rafts produced 12 of the 14 (86%) chicks hatched lakewide. Seven nests were abandoned due to unknown reasons. Of successful 20 hatches, 12 chicks survived to fledge.

INTRODUCTION About the Study Site In 1911, the Aziscohos Dam was built on the Magalloway River in northwestern Maine (Figure 1). The impoundment was built with the intention of increasing water storage in the Upper Androscoggin Storage System. The water flow was regulated to supply a steady flow of water year round for downstream mills, which used mechanical waterpower. The existing river, riparian zones and upland were transformed into an 11.53 square-mile (7378-acre) impoundment that extended across sections of three townships (Parkertown, and Lynchtown and Lincoln). A hydroelectric facility was built in 1984 and became commercially operational in 1985. At present, a 21-mile long meandering lake exists with various shoreline substrates ranging from boulders at the south end to granular sand towards the north end. The impoundment also contains habitat for several lacusterine wildlife species, including the Common Loon. As a consequence of water level management operations, water level fluctuations frequently occur within the loon’s nesting period. These fluctuations can affect loon nesting habitat and nesting success. History And Purpose Of Study During the licensing of the new hydroelectric facility installed at the existing dam in 1984, the Androscoggin Reservoir Company (ARCO) and Aziscohos Hydro Company, Inc. conducted numerous environmental studies. These studies revealed that the water level fluctuations during the summer were negatively impacting the nesting success of the Common Loons. Androscoggin Reservoir Company (ARCO) and Aziscohos Hydro Company, Inc. submitted a report and management plan to the Federal Energy Regulatory Commission (FERC). FERC approved the loon management plan and incorporated it into article 33 of FERC License No. 4026-002ME (Fair 1986). ARCO was required to survey the Common Loon population in order to evaluate the necessity and feasibility of the use of artificial nesting islands on Aziscohos Lake. It was also required to submit a report that would “draw up full recommendations for an implementation plan for the manufacture, placement, and maintenance of artificial nesting islands determined necessary” (Fair 1986). Since 1987, the Common Loon population on Aziscohos Lake has been surveyed and managed using artificial nesting islands by Jeff Fair [consulting biologist, Fairwinds Wildlife Services (FWS)] and Bill Hanson (Senior Biologist, Central Maine Power Co.) in accordance to the FERC order. In 1999, FPL (FPL Energy Maine Hydro) became a partial owner of the Aziscohos Dam and assumed 2

2003 Aziscohos Lake Common Loon Survey and Management Report

responsibility for the project. BioDiversity Research Institute (BRI) has conducted research and surveys on Aziscohos since 1994, and has been responsible for conducting loon surveys, management, and the preparation of this annual report since 1999. BRI biologists have worked with Jeff Fair and Bill Hanson (now Senior Biologist, FPL Energy Maine Hydro) at Aziscohos Lake to ensure thorough standardization of survey techniques and definitions to minimize observer bias during this transition. This long-term cooperative initiative between ARCO, FPL, FWS and BRI has resulted in one of the most thoroughly and well-studied loon populations in the U.S. OBJECTIVES 1.

To continue the existing loon-management and monitoring project on Aziscohos Lake. We will monitor and quantify loon nesting activities as well as the factors affecting the productivity of the current dynamic Common Loon population on Aziscohos Lake.

2.

To implement and evaluate the effectiveness of artificial nesting islands (rafts) within loon territories. We will make recommendations on the improvement, addition, removal, and placements of according to guidelines formulated in the management plan.

3

To evaluate and identify key high-quality loon habitat on Aziscohos Lake using long-term territory reproductive success as an indicator.

3

2003 Aziscohos Lake Common Loon Survey and Management Report

METHODS1 1. POPULATION AND NESTING SURVEYS We regularly surveyed Aziscohos Lake to confirm the presence/absence of Common Loons and document their nesting activities from 15 May to 18 August 2003 (Table 1). The bulk of the survey effort was concentrated on the Common Loon nesting onset and hatching period from May through July. Survey methods were consistent with those reported by Fair (1986) and Fair (1999), with additions to address objectives 2 through 5. We surveyed all known territories and surrounding areas on Aziscohos Lake from 14-18’ motorboats using 10X binoculars and occasionally a 15-45X spotting scope. Every effort was made to gather information from the greatest distance possible in order to minimize impacts on nesting and brooding activities. Since nesting evidence may be obscured by vegetation, it was often necessary to search for presence/absence of nest evidence by foot. We performed searches for evidence of natural nesting attempts by walking the perimeter of the available nesting habitat in loon territories. All known historical nesting sites previously reported by Jeff Fair and Bill Hanson were checked regularly for nesting evidence both above and below the waterline in response to fluctuating water levels. TABLE 1: Lake Survey visit record for 2003 on Aziscohos Lake, Maine.

Month Visit dates May 15, 21, 27, 28, 29 June 4, 6, 11, 12, 19, 20, 23, 26 July 3, 21, 29, 30 August 1, 6, 18 TOTAL: 20 visits 2. LOON MANAGEMENT TOOLS: RAFTS, AVIAN GUARDS AND SIGNS Raft Implementation In early May, BRI and FPL biologists floated rafts constructed from cedar logs (nailed together using ~8 inch galvanized spikes) and plastic “mesh” fencing (attached using 1-1/2 inch galvanized fencing staples) similar to those described in Fair (1986) and Fair (1992a). We placed vegetation, consisting of material found in the general nesting area (sphagnum moss, grasses, and other vegetation), on all of the rafts, for loons to use for nesting material. Common Loons typically build their nests from materials gathered from the immediate vicinity of the nesting site (McIntyre 1988). Nesting materials were built up to levels at which the eggs would remain dry and be well above the water surface. We monitored all rafts periodically for proper placement, buoyancy, and sufficient nesting materials throughout the season. All rafts were pulled out of the water to a point that was above the highest possible waterline to dry for the winter (after all nesting activities ceased). Raft positioning and location was determined by 1) knowledge of wind and wave action patterns relative to each territory, 2) knowledge of loon territorial boundaries and proximity to other territories (the importance of this point is addressed in the Discussion) 3) knowledge of previous traditional and non-traditional nest 1

Terms used in this report are defined in Appendix 4.

4

2003 Aziscohos Lake Common Loon Survey and Management Report

site locations and 4) knowledge of boat traffic patterns relative to the specific territory (This is important relative to the orientation of the avian guard, which obscures the view to/from the nest on two sides of the raft). Avian Guards Before raft floatation, we continued the practice of attaching (using staple-nails) avian guards made of metal fencing and camouflage mesh, to all rafts, as was initiated by Jeff Fair in 1988 (Fair 1992a). Avian guards are effective in lessening raft visibility and nest exposure from aerial predators and human lake users2, which decreases flushing events and disturbances to nesting loons. Avian guards may therefore increase incubation time and hatching success of raft nesting loons. Camouflage mesh material was removed at the end of the season to avoid further degradation. Signs Several pairs on Aziscohos Lake have failed due to disturbance by humans. Many of these disturbances are unintentional and may be avoided by placing informational signs both at the launch sites and at some nesting/brooding areas where deemed necessary. FPL Energy Maine Hydro distributes signs (“Loon Nesting Area Please Keep Away”) for use in protecting these areas from human disturbances. The decision of whether or not to place a sign in a territory is often a difficult one based on their variable effectiveness as management tools. The character of and type of lake users as well as the configuration of the territory and location of nest site will influence their efficacy. Sign placements are based on previous reports’ recommendations, knowledge of typical lake use patterns and previous site-specific nest failure history. Signs were not implemented before nesting activity had been found (and were therefore not used for territorial pairs which did not attempt nesting), and should be taken down after nesting and/or brooding activities cease. They were also not implemented in cases where it was determined that their cost (potentially attracting attention to a nest site) outweighed the benefit (notifying unsuspecting lake users to stay away). We did not use signs in 2003 and do not discuss them further in this report. 3. ABANDONED EGG COLLECTION We collected abandoned Common Loon eggs whenever possible to determine 1) egg viability as indicated by developmental stage and 2) egg mercury concentration. Information gathered from these analyses provides insight into causes of nest failure. Collection of Eggs Loon eggs were not collected unless abandonment or failure could be confirmed beyond a reasonable doubt. We attempted to immediately collect abandoned eggs before they were predated or destroyed. When uncertainty existed in the determination of the absolute abandonment of the eggs by the adults, we gently penciled an “X” on the “upside” surface of the egg(s) in question. Eggs were checked no 2

Fair (1992) notes that avian guards may actually increase the visibility of rafts and will therefore increase the likelihood of human disturbance and resultant nest failure. We have found this to be the case on some territories, although we felt avian guards actually helped conceal rafts and nesting loons in several Aziscohos territories.

5

2003 Aziscohos Lake Common Loon Survey and Management Report

less than 24 hours later. Those that had not been turned by an incubating loon were considered inviable and were collected, placed in a labeled zip-lock plastic bag, and frozen until egg analysis. Egg Sample Analysis For each egg, we measured and recorded the length, width, volume (through water displacement), and weight. Evidence of external damage was noted. Eggs were then cut open, their contents were rated for embryological development (based on the scale below), and contents were placed in sterile I-Chem® jars. Egg contents were analyzed for mercury concentration using cold vapor atomic absorption, and eggshells were archived. Embryological development scale used for Common Loon eggs NA (not assessable): Developmental stage could not be determined. Contents were gray or yellowish-tan in color and typically had a foul smell. A darker color suggested some degree of development had occurred, whereas a yellow homogeneous liquid may be sifted through and if no dark spots or hardened areas were found we classified the egg as infertile (0). 0:

No development was evident. Egg had a yellow/orange or yellow/tan yolk (intact or broken down into a liquid). A translucent jelly-like mass surrounded the yolk sac and showed no sign of embryonic development (e.g. mass not dark or hardened).

1:

Embryo was viable (length was up to 1.5 cm). The jelly like mass (embryo) was dense and hardened. Small dark (red) eyespots may be visible at this stage.

2:

Developing embryo (length was 1.5 – 2.0) has an apparent central nervous system. Cranial development and visible eyes are apparent. Feathers are absent.

3:

The embryo shows advanced development (length was 2-3 cm). Bill was developed (e.g. egg tooth present but soft). Legs and wings were visible but not fully developed. Some feathers were present (first seen in tail).

4:

The fully developed embryo was completely covered by feathers. Appendages were completely developed. Vent, preen gland was visible. A small portion of yolk sac remained attached to belly. ____________________________________________________________________________________________________________

4. SURVEYING FOR MARKED INDIVIDUALS We surveyed for color-marked loons that were captured on Aziscohos Lake from 1994 – 2003 [using a night-lighting technique described in Evers (1993) and Evers (2001)] to gain further information on territory boundaries, between-year territory fidelity, mate switching, estimated minimum survivorship, intra-seasonal movements, and recruitment. Each captured individual was custom fitted in the field with one or two bands on each leg (one USFWS band plus 1-3 color bands per bird), which are then observed opportunistically during surveys using a pair of 10X binoculars. Bands are often visible above and below the water, depending on light conditions and wave action. The color combination observed in the field was recorded, and later referenced a color banded loon ID list to confirm the individual(s). We also recorded the location and general behavior of both banded and unbanded individuals at the time of observation. 5. EVALUATION OF HABITAT QUALITY The overall number of chicks fledged (F) is our best indicator of population productivity and habitat quality. We have evaluated habitat quality on Aziscohos Lake by analyzing long-term chick survival 6

2003 Aziscohos Lake Common Loon Survey and Management Report

data on all recognized territories (no. chicks Fledged/ no. years surveyed). Territories were placed into the following six categories for habitat quality developed for a similar study of Lake Umbagog (Evers 2000): extra low (0 - .10), low (0.11 – 0.31), moderate-low (0.32 – 0.52) moderate-high (0.53 – 0.73), high (0.74 – 0.93), and extra-high (>0.93). Categorical habitat quality data was then georeferenced using ESRI® ArcView™ software. The resultant map can then be used to identify key reproductive habitat on Aziscohos Lake (Figure 3). RESULTS AND DISCUSSION 1. POPULATION AND NESTING SURVEYS: PRODUCTIVITY SUMMARY 2003 We present productivity information for the Aziscohos Lake loon population for the 2003 season. We summarize overall lakewide productivity, nest failures, renests, the development of new territorial pairs, and the development of new nesting pairs. Territory-specific productivity data is summarized in Appendix 1 and the Qualitative Territory Summary. TABLE 2: Common Loon Productivity and Nesting Summary (2003). Territory-specific productivity details are summarized in Appendix 1 and The Qualitative Territory Summary. 21 Territorial Pairs 13 Nesting Pairs 13 Nesting Attempts 0 Renests 8 Successful Pairs 14 Chicks Hatched from all territories 4 Chicks Fledged from all territories 5 Nest Failures 2 (40%) Nest Failure due to unknown cause 2 (40%) Nest Failure due to increase in water level 1 (20%) Nest Failures due to mammalian predation ____________________________________________________________________________

Overall Lake-wide Productivity Summary We observed 21 territorial pairs on Aziscohos Lake in 2003 (Table 2). Thirteen of the 21 territorial pairs nested, totaling 13 nesting attempts lake-wide (Table 2). The 2003 nesting frequency was 62% (13 NP/21 TP). Eight pairs were successful in hatching a total of 14 young, with 4 chicks surviving to fledge. This yielded a nesting success (SNP/NP) of 61%, and 29% chick survival. The hatch rates for both nesting pairs (H/NP) and territorial pairs (H/TP) are 1.08 (14/13) and 0.67 (14/21), while corresponding fledge rates (F/NP and F/TP) are 0.31 (4/13) and 0.19 (4/21).

Nest Failures There were a total of five nest failures on Aziscohos Lake in 2003 (Table 2). Thirty-six percent (5/14) of the attempted nests failed. This is approximately 0.28 nest failures per nesting pair. Two nest failures (40%) were not fully understood and were designated as unknown. Two nest failures (40%) were attributed to an increase in water levels. One nest failure (20%) was due to mammalian predation. 7

2003 Aziscohos Lake Common Loon Survey and Management Report

Renests None of the 14 nesting pairs renested on Aziscohos Lake in 2003 (Table 2). Qualitative Territory Summary (Aziscohos Lake, 2003) Reporting productivity data in a quantitative summarized form often inadvertently overlooks some important details. We report territory-specific information here in a qualitative descriptive format to minimize this potential loss of information. All territories and other areas of interest are listed from north to south. Territories displaying a “(R)”, represent those in which a raft was floated; all others display no raft (“nR”). Quantitative data about these territories (including specific dates) is found in Appendices 1-3. Little Magalloway (nR) A pair occupied the Little Magalloway territory this season. The male banded in 2002 returned with a banded female, although her bands could not be confirmed. The pair nested naturally in an area that differed from their known traditional sites, in the small marshy cove along the west shoreline south of the traditional nesting island. The nest flooded due to torrential downpours and flooding that resulted from it during mid-June. One egg was collected, and no further nesting evidence was found throughout the season. Sunday Pond (R) The banded female occupied the Sunday Pond territory with an unbanded male. The pair nested, laying two eggs on the raft during the first week of June. The pair was observed incubating the eggs during the next several visits. During these weeks one of the eggs went missing. Based on nesting evidence (membranes observed in the water under the raft), one chick appeared to have hatched during the middle of July, but was never confirmed. The chicks most likely hatched and disappeared within the first few days of age. Twin Brook (R) The pair banded in 2002 returned this season. A nest dish was found at the end of July on the rocky shoal in front of the Twin Brook campground, although no eggs or chicks were ever observed. This pair was not considered a nesting pair for reproduction calculations. Bosebuck (nR) The banded pair returned to the Bosebuck territory this season. The pair nested naturally on their traditional nesting island on the next sandy beach just south of ther traditional nesting location. Two eggs were laid in a natural nest, which the birds continued to incubate despite water level decreases and an approximately five-foot runway to the nest. The nest failed due to mammalian predation in early August, just prior to hatching. The previously banded Bosebuck female was consistently observed in the Little Magalloway river channel, between the Sunday Pond entrance and Bosebuck camp. This female was seen interacting with the pair, but is thought to have likely formed a new territory in the river channel this season. Camo Camp (R) The Camo Camp territory was occupied this season by the Twin Brook male and an unbanded female. The pair laid two eggs on the raft in mid June,, both of which hatched. One chick was lost in early August, and the other survived. The Twin Brook female that occupied the territory last season was observed on territory with the newly occupying Twin Brook Male during mid June, the survey prior to the onset of nesting. The South Cove male was not confirmed this 8

2003 Aziscohos Lake Common Loon Survey and Management Report season. This territory thus contained a complete pair switch from last year, however the female may have been on territory prior to nesting. Raven (R) A banded pair occupied the Raven territory this season, the traditional male and the female banded in 2001 who was not observed in 2002. They laid two eggs on the raft the first week of June. One egg appeared to have hatched, while the other remained intact and rotten on the nest. The chick was never confirmed on territory with the adults. The pair did not attempt to renest. Hurricane (R) The Hurricane territory was occupied this season by the Buck Mountain male of 2000 and the Hammel Brook female of 1996. The pair nested on the raft for the first time since it' s flotation, laying two eggs. Both eggs hatched, however one chick was found dead on the nest. The other chick was confirmed with the adults. The pair used much of the territory to brood the young, including the eastern shoreline. The chick was observed on the last survey in August, at that time the chick was approximately six weeks old. Hammel Brook (R) The Hammel Brook male returned after not being observed during the 2002 season, with an unbanded female. The pair laid two eggs on the raft. Both eggs hatched, although one of the hatched young was found dead on the nest; the other chick was with the adults. The chick was observed on the last survey in August, at that time the chick was approximately seven weeks old. Buck Mountain (R) The banded Buck Mountain female returned to the Buck Mountain territory this season with an unbanded male (The former banded Buck Moutain male occupied the Hurricane territory this season). The pair nested, laying two eggs on the raft in early June. Both chicks hatched, however one was found dead and decomposed on the nest. Chick was observed on final survey in August and was approximately 6 weeks old at that time. Yukon (nR) Pair was observed in territory this season. It appears this pair did not attempt to nest. Big Brook (R) The Big Brook pair was not present on their historical territory this season, however they were observed in the middle of the lake on occasion. The banded Big Brook female was confirmed with and unbanded male. A raft was floated in the cove, which was not used. The pair was never observed in their traditional nesting cove all season. This pair is thought to have moved north to Yukon or just did not occupy either site. Meadow Brook (nR) The Meadow Brook pair occupied the territory this season and nested in early June on their traditional grassy spot in the middle of the cove. This pair was only found on territory intermittently, and both adults were only assumed to be unbanded again this season (no raft floated). One very recently laid egg was found in a half inch of water in a partly flooding nest. The nest was built up to a foot above its current level in anticipation of increasing water levels. The nest flooded in the torrential rains in June, the nest was under a foot of water despite manipulations. The egg was found underwater in the nesting material and was collected. The pair was irregularly found on territory following the nest failure. North Hammond (R) 9

2003 Aziscohos Lake Common Loon Survey and Management Report The South Hammond female of 1998 occupied the North Hammond territory with an unbanded male. The pair built a nice dish on the raft, but no incubation activity or evidence of eggs was ever confirmed. The pair remained tight to the nesting cove and the raft throughout much of the season. No nesting activity was found on natural sites. South Hammond (R) A pair was observed throughout June this season. The pair made no nesting attempts. Tiger Gray (R) The banded pair returned the Tiger Gray territory this season. The pair built a nest dish on the raft during late June, but eggs were never confirmed, therefore it was not counted as a nesting pair. The banded Tiger Gray pair was observed on 6/20; and a pair was observed tight by the raft on 6/26. However, an unbanded pair was observed roughly a week later on 7/3. This unbanded pair may have interfered with the nesting activities of the resident pair. Aldrich Brook (R) The unbanded Aldrich Brook pair returned to their territory this season. A raft was floated in the brook again this season that was not used, and no natural nesting evidence was found. The Tiger Gray pair and individuals in the Lincoln Brook area were frequently seen interacting with this pair. Cold Brook (R) The banded Cold Brook pair returned to their former territory this season. They nested on the raft during the first week in June, laying two eggs. An adult was observed incubating one of the two eggs on the raft; the other was not present during the third week of June. The egg remaining on the raft contained a pinkish fleshy material on the shell, it was later confirmed to be rotten and was collected. This is the second time recently that a single egg has vanished from the nest on this territory. It is suspected that mammalian or avian predators were chased away by the resident loons incubating, however this is pure speculation. We categorized this failure as unknown. Emery’s Misery (R) The Emery' s Misery pair occupied the traditional territory this season. The banded male of 1998-1999 returned after three years of not being observed, with an unbanded female. The pair nested on the raft in early June, and nesting evidence indicated a hatch (eggshell fragments and membranes on raft) in July, however no chicks were ever observed. Grove (R) The unbanded Grove pair returned to their territory this season and nested naturally, laying two eggs on the north shore within their territory behind the Herring gull nesting colony. (The raft was not floated this season due to a lack of a proper placement location). The nest appeared to have hatched; eggshells and membranes were present on the nest. The chicks were never confirmed, and the adults were not observed on territory regularly late in the season. Beaver Brook (R) The Beaver Brook pair occupied the Beaver Brook territory this season. Both individuals were unbanded, although it is worth noting that the Beaver Brook female of 1997- 2001 was confirmed to be on the Dam territory with the banded male. The Beaver Brook pair nested, laying two eggs on the raft during the first week of June. The nest apparently failed in July, seemingly to unknown predation. Very little nesting material was found on the nest and no chicks were observed in the territory. Beaver Island (nR) The unbanded Beaver Island pair returned to the territory this season, but was not consistently on territory. The pair was frequently seen near the grassy spot east of their traditional nesting island. No nesting evidence was discovered on any sites. 10

2003 Aziscohos Lake Common Loon Survey and Management Report

Dam (R) The traditional banded Dam male returned to his territory this year with the 1997 banded female from Beaver Brook. No nesting evidence was found. The pair was quite mobile within their territory this season, spending time near the dam and along the west shore, near the large boulders used for nesting by Herring gulls (not the grove shoal). Lincoln Brook A pair was seen occasionally in one of the following areas: Lincoln Brook, the deep fishing hole schist coves, and on the eastern shoreline across from the Hammond territories, north of the deep fishing hole. One banded bird was confirmed on several occasions (left leg = a single white or silver band), but this did not fully confirm the identification of the individual (Possibly an ABJ). These areas should be continually watched in the future for the development of territorial pairs and nesting activity. The eastern shoreline across from the Hammonds should be surveyed regularly next season.

2. LOON MANAGEMENT TOOLS: RAFTS, AVIAN GUARDS Raft Implementation We reinforced, floated, vegetated, positioned and maintained 17 rafts in 17 loon territories (See Appendix 2 and territory maps for territory-specific information). All rafts were pulled out of the water in early September above the highest possible water level to dry over the winter. Avian Guards Avian guards were used on all 17 rafts this season. Upon pulling the rafts above the water line in September, all of the camouflage material was removed, and will be re-applied to the rafts floated in 2004.

11

2003 Aziscohos Lake Common Loon Survey and Management Report

Raft Vs. Natural Nest Site Summary This section is intended to provide the information necessary to evaluate the effectiveness of rafts as a management tool. We compare productivity, renests, and nest failures between loon pairs choosing raft and natural nest sites in 2003 (Territory-specific nesting information is presented in Appendix 2 and the Qualitative Territory Summary). TABLE 3: Common Loon Comparative Nesting Summary: Rafts vs. Natural Nests (2003) Raft Sites: 17 rafts floated in 17 territories (out of a potential 22) 9 of 17 (53%) rafts used for nesting by loons 9 of 11 (82%) nesting attempts in raft-containing territories were on rafts 9 of 14 (64%) lakewide nesting attempts were on rafts 7 of 9 (78%) nesting attempts on rafts were successful 9 of 9 (100%) nesting attempts on rafts were 1st attempts 0 of 9 (0%) nesting attempts on rafts were 2nd attempts 0 of 0 renests were on raft sites 12 of 14 (86%) chicks hatched (H) lakewide from raft nests 4 of 4 (100%) chicks fledged (F) lakewide from raft nests Nest Failures: 2 nest failures on rafts 2 of 2 (100%) nest failures on rafts were not fully understood and were designated as unknown Natural Sites: 5 of 14 (36%) lakewide nesting attempts were on natural sites 1 of 4 (25%) nesting attempts on natural sites were successful 4 of 4 (100%) nesting attempts on natural sites were 1st attempts 0 of 4 (0%) nesting attempts on natural sites were 2nd attempts 0 of 0 Renests were on natural nest sites 2 of 14 (14%) chicks hatched (H) lakewide from natural nests 0 of 4 (0%) chicks fledged (F) lakewide from natural nests Nest Failures: 3 nest failures on natural sites 2 of 3 (67%) nest failures on natural sites were due to an increase in water level 1 of 3 (33%) nest failures on natural sites was due to mammalian predation

Raft vs. Natural Nest Site Productivity Rafts were instrumental in increasing productivity on Aziscohos Lake in 2003. As demonstrated in other studies (Fair and Poirier 1992, Merrie 1996) loon productivity can be substantially enhanced on waterbodies with significant fluctuations in water levels with rafts. Water level fluctuations do not appear to impact nesting activities of raft-nesting loons as long as the rafts are properly placed and maintained throughout the season. Sixty-four percent (9/14) of all nesting attempts on Aziscohos Lake in 2003 were on rafts. While, thirty-six percent (5/14) of all nest attempts consisted of natural sites. Eighty-eight percent (7/8) of the successfully nesting pairs on Aziscohos Lake were pairs that used raft nest sites. Only twelve percent (1/8) of successfully nesting pairs lake-wide, used natural 12

2003 Aziscohos Lake Common Loon Survey and Management Report

nest sites. Eighty-six percent (12/14) of the total number of hatched chicks were from rafts, while only fourteen percent (2/14) of the total number of hatched chicks were from natural sites. When comparing natural vs. raft nesting attempts, we have found that raft selection seems to be either individual or site influenced, and have not yet found a method that is successful in influencing a pair’s choice of a nest site. Nonetheless, in the 17 territories where rafts were floated, 9 of them were used, accounting for 81% of the nesting attempts in raft-containing territories. Lakewide, 69% of the nesting attempts were on rafts. Rafts vs. Natural Nest Sites: Failures There were three nest failures on natural sites (60% of all failures). Thirty-three percent of all failures on natural sites were due to mammalian predation and sixty-seven percent of the nest failures on natural sites were due to an increase in water level. There were two nest failures on raft sites (40% of all failures). One hundred percent of the nest failures on rafts were not fully understood and were reported as an unknown cause of failure. Rafts vs. Natural Nest Sites: Renests There were no renests on Aziscohos Lake during the 2003 season.

13

2003 Aziscohos Lake Common Loon Survey and Management Report

3. ABANDONED EGG COLLECTION AND ANALYSIS Developmental stages of the following abandoned eggs collected in 2003 are listed3. One of the five eggs collected in 2003 were found to be not viable. The Cold Brook egg was viable, containing an embryo in advanced development. The Meadow Brook egg was actually a fully developed hatched chick, still attached to the egg sac. The development of two of the eggs (Raven and Little Magalloway) could not be determined. No. eggs collected Raven 1 Cold Brook 1 Little Magalloway 1 Meadow Brook 1 Hurricane 1

Dev. Stage4 n/a 3 n/a 0 4

4. EVALUATION OF HABITAT QUALITY We have evaluated habitat quality on Aziscohos Lake by analyzing territory-specific productivity over time (# chicks Fledged/ # years surveyed). We used 17 years of chick survival data on 22 recognized territories. Territories were placed into the following six categories for habitat quality developed from the 24-year mean for Lake Umbagog (Evers 2000) (nest site selection5 is noted for each territory): extra low low moderate-low moderate-high high extra-high

(0.00 - 0.10) (0.11 – 0.31) (0.32 – 0.52) (0.53 – 0.73) (0.74 – 0.93) (>0.93)

No territories rated in the extra-high or high categories (Table 4). Five territories (23%) were rated moderate-high: Emery’s Misery (R), Hammel Brook (R), Sunday Pond (R), Camo Camp (R) and Beaver Brook (R). Six (27%) were rated moderate-low: Big Brook (n/r), Bosebuck (N), Little Magalloway (N), South Hammond (R), Twin Brook (R) and Hurricane (R). Six territories (27%) were rated low: Buck Mountain (n/r), Cold Brook (n/r), Dam (n/r), Meadow Brook (N), Raven (n/r), and Tiger Gray (n/r). Five territories (23%) were rated extra-low (all territories have not yet fledged young): Aldrich Brook (R), Beaver Island (N), Yukon (N), North Hammond (n/r), Yukon (N) and Grove (R). These data have been used to georeference key reproductive habitat on Aziscohos Lake (Figure 3).

3

Further details on individual nest failure causes and abandonment are presented in the Qualitative Territory Summary. Egg developmental codes explained in Methods. 5 Territories in which rafts were used are denoted with an R, naturally nesting loon pairs are denoted by N, and those that have used both natural and raft sites for nesting are denoted by n/r. 14 4

2003 Aziscohos Lake Common Loon Survey and Management Report

Several variables confound habitat quality data on highly managed reservoirs such as Aziscohos Lake. Loon territory quality is likely not constant over time. Due to the success of management using rafts on Aziscohos Lake, raft-nesting loons have a significant reproductive advantage over naturally nesting loons. Therefore, productivity data is directly linked to nest site selection for breeding pairs, and should be considered when comparing between and/or evaluating habitat quality. Several other factors [Water level fluctuations (by affecting the amount of available nesting habitat), human activities, abundance of predators, vegetative features and loon social dynamics) influence loon habitat quality over time on Aziscohos Lake. We have identified differential use of rafts by nesting loons, water level fluctuations, and habitat configuration as the most important factors. A tendency exists on Aziscohos Lake for the more productive territories to be located in protected coves (e.g. Sunday Pond, Emery’s Misery, Beaver Brook, and South Hammond) – where a greater percentage of the boundary of their territory is land instead of water (Figure 4). This characteristic of a territory is likely related to habitat quality, as it is likely related to intrusion rates. Evers (2000) reported a similar tendency on Umbagog Lake territories in the Magalloway River. Territories with a higher percentage of water boundary in their territory are likely to face more intrusions by neighboring and non-breeding loons. This may result in a greater threat to the survival of the young, and higher energy expenditure by the adults. The low categorization of the Tiger Gray, Grove and Dam territories may be related to their open configurations. Intruders are often observed in these areas. Physical measurements in each territory would help address this factor. Most transitional and very recent territories (Aldrich Brook, North Hammond, and Yukon), unsurprisingly, were found to be extra low – these may be the lower quality habitats remaining on Aziscohos Lake, the higher quality territories already being occupied. Data for these territories represent very few years. It is very possible that the Beaver Island territory is negatively impacted by human activity. The territories traditional nesting location consists of an island, which contains an active campsite, heavily used throughout the loon’s nesting season.

15

2003 Aziscohos Lake Common Loon Survey and Management Report Table 4. Habitat Quality Ranking within loon territories using long-term reproductive means, Aziscohos Lake, 19872003 (see page 19 for habitat quality categories). Territory TP-years CS Ranking Category 5 0 0.00 extra low Aldrich Brook 17 12 0.71 mod-high Beaver Brook 4 0 0.00 extra low Beaver Island 15 5 0.33 mod-low Big Brook 17 6 0.35 mod-low Bosebuck 12 3 0.25 low Buck Mountain 3 2 0.67 mod-high Camo Camp 17 3 0.18 low Cold Brook 17 4 0.24 low Dam 17 9 0.53 mod-high Emery’s Misery 5 0 0.00 extra low Grove 17 10 0.59 mod-high Hammel Brook 17 6 0.35 mod-low Hurricane 16 7 0.44 mod-low Little Magalloway 16 2 0.13 low Meadow Brook 6 0 0.00 extra low North Hammond 11 2 0.18 low Raven 17 8 0.47 mod-low South Hammond 17 9 0.53 mod-high Sunday Pond 16 2 0.13 low Tiger Gray 16 6 0.38 mod-low Twin Brook 4 0 0.00 extra low Yukon Lake Total (87-03) 280 96 0.29 mod-low

In summary, the lakewide productivity average on Aziscohos Lake is 0.296 (96chicks F/ 280 terr-yrs, 1987-2003). Eleven Aziscohos Lake territories (50%) were above this lakewide average. The Aziscohos Lake mean was lower in comparison to the 24-year mean for Lake Umbagog (0.46 +/0.31), and significantly lower than the statewide mean for NH (0.52 +/- 0.09). It is a generally true for most avian species that 15% of a population is responsible for producing 50% of the young (Newton 1992). Five (23%) territories7 on Aziscohos Lake were rated above the moderate low category, and those five territories (or 24% of the Aziscohos Lake population) are responsible for producing 43% of the total fledged young produced on Aziscohos Lake over the course of this monitoring effort. These findings emphasize that not all territories have an equal value in terms of productivity, which should be reflected in management efforts. 5. LATE-SEASON CHICK MONITORING AND OVERALL CHICK SURVIVAL Since nesting activities are typically concluded by the early fall, survey efforts are usually not carried out past this point in the season. For the most part, the productivity parameters for the population can be accurately collected using this survey schedule. The one exception, however, has been the number of chicks fledged (F). Once a loon chick reaches the age of six weeks, it’s chances of survival on its natal lake increase dramatically. Typically, loon surveys calculate the number of chicks fledged as being the number of chicks surviving past eight weeks of age. This season, we carried out our loon monitoring into late August in order to: 1) confirm juvenile survival past the six-week period and 2) 6 7

This figure represents total fledged Lakewide/total no. territory years and includes all territories. Calculations included only territories that had >2 territory years.

16

2003 Aziscohos Lake Common Loon Survey and Management Report

determine where and how long juveniles remain on/in their natal lake/territory in the fall. As juvenile loons get older, they become more mobile and are difficult to confirm. Territory-specific chick survival and confirmation dates are listed by territory in the Qualitative Territory Summary, while the hatch windows used in these calculations can be found in Appendix 3. Four territories on Aziscohos Lake lost their young entirely before fledging (Emery’s Misery, Raven, Grove and Sunday Pond). The Emery’s Misery and Grove pairs both incubated two eggs, which appear to have hatched due to small pieces of eggshell fragments and membranes found on the nest. In both cases the adults were seen on territory without any chicks. Most likely they disappeared within the first few days of hatching. The Raven pair incubated two eggs, when the nest was checked for evidence of hatching, one whole rotten egg was found on the nest and there was evidence the second egg hatched although no chick was ever observed. The Sunday Pond pair appeared to have hatched one chick and the other egg disappeared sometime during incubation. Eggshell membranes were seen in the water under the nest, but no chick was ever observed It appeared to have disappeared within the first few days of hatching. Four pairs each fledged a single chick from Aziscohos in 2003 (Buck Mountain, Camo Camp, Hammel Brook and Hurricane pairs). All four of these pairs hatched two chicks, although only one survived to fledge. Each of these pairs hatched two chicks from a raft and for three of the pairs (Buck Mountain, Hammel Brook and Hurricane), one of the chicks was found dead on the nest. In the fourth territory (Camo Camp) one of the chicks disappeared early in August due to unknown reasons. In summary, 71% (9/14) of all chicks hatched survived between 0-5 days, 7% (1/14) survived 6-23 days and the remaining 29% (4/14) survived to reach a minimum of 23-84 days. All surviving juveniles were confirmed in the general vicinity of the territory from which they were hatched, but increased their mobility with age. The 25-year average for the entire NH population is 76% (Taylor and Vogel in prep.). These findings suggest a significant impact on chick survival on Aziscohos Lake that warrants further investigation. 6. PRODUCTIVITY SUMMARY (2003) COMPARISON TO LONG TERM MEANS (1987-2002) There were several notable changes in the general Aziscohos population in comparison to long term means (Table 5). Most notably, we observed a 25% increase in territorial pairs, and an 22% decline in nesting frequency, in comparison to the long-term Aziscohos mean. In general, productivity measures related to hatching and nesting success notably increased (e.g, a 52% increase in the no. of chicks hatched; a 32% increase in nesting success), while measures related to fledging decreased (e.g., 57% and 37% decrease in chick survival and the fledge rate (CS/NP), respectively). The chick survival rate of 29% observed in 2003 is notably lower than the long-term 23-year for the statewide New Hampshire population (77%). Higher territorial and nesting pairs, with simultaneous decreases in chick survival, but not hatching measures suggests that (1) the lake population is increasing, (2) management efforts are effective to maintain a viable level hatching success, and (3) limitations beyond hatch limit the ability of pairs to successfully fledge young. These characteristics may represent density-dependent impacts for this population.

17

2003 Aziscohos Lake Common Loon Survey and Management Report TABLE 5: Common Loon Productivity on Aziscohos Lake from 1987 –2003, with comparisons to calculated longterm means8. Parameter Territorial Pairs (TP)

Nesting Pairs (NP)

Nesting (NP/TP) Frequency Successfully NP (SNP) % Nesting Success No. Chicks Hatched (H) No. Chicks Fledged (F) % Chick Survival (CS/CH) Hatch Rate (H/NP)

Fledge Rate (CS /NP)

Hatch Rate (H/TP)

Productivity (CS/TP)

% Ch.

1986

87-89

90-92

93-95

96-98

99-01

02

2003

87-02

10.0

13.3

14.6

16.3

17.0

20.3

19.0

21

16.8

25

4.0

10.6

12.0

12.3

13.6

16.0

16.0

13

13.4

12

40%

80%

82%

75%

81%

79%

84%

62%

80%

-22

2.0

4.0

6.3

5.6

6.3

5.3

10.0

8

6.3

27

50%

37%

52%

46%

47%

33%

63%

61%

46%

32

3.0

6.0

10.0

7.6

8.6

8.0

15.0

14.0

9.2

52

2.0

5.3

8.0

6.0

5.6

4.0

6.0

4.0

5.8

-31

67%

94%

80%

77%

64%

50%

40%

29%

68%

-57

0.75

0.55

0.85

0.63

0.63

0.50

0.94

1.07

0.68

57

0.50

0.72

0.68

0.49

0.41

0.25

0.38

0.31

0.49

-37

0.30

0.44

0.68

0.47

0.52

0.39

0.79

0.67

0.55

22

0.20

0.39

0.54

0.37

0.34

0.20

0.32

0.19

0.36

-47

7. YEAR 2003 RECOMMENDATIONS 1. Raft Management and Placement: Raft locations, Maintenance & Replacement: All rafts appeared to be in good working condition and are not in need of replacement in 2004. The grove raft should be removed due to the lack of a suitable site. 2. Surveying for new Nesting and Territorial Pairs: If new pairs become established on Aziscohos Lake, it is likely that they may move into presently vacant but previously occupied areas or areas in which individuals are occasionally observed. We recommend close monitoring of the following areas in addition to all of the territories recognized in 2002. Lincoln Brook and Aldrich Camp: We recommend close monitoring of these areas to detect development of new territorial individuals and to understand local territory dynamics. North Hammond Area: The Cove to the north of the North Hammond territory (Figure 2) contained occasional pairs this in previous seasons. It seems as though the North Hammond pair occupies this cove occasionally. This cove should be monitored for loon activity throughout the season. South Hammond/Schist Coves Area: The rocky irregular shoreline east of the South Hammond territory and west of the Lincoln Brook area (“Schist Coves”) occasionally contained individuals. Considering the growth in this general vicinity over the last few years, this area should be monitored for new pairs and nesting activity. 8

Data for Table 6 used from Fair 1992b, 1997, DeSorbo and Evers 2000, DeSorbo and Evers 2001, and Savoy et al 2002a). Explanations for all Parameters are listed in the Definition of Terms section (Appendix 4).

18

2003 Aziscohos Lake Common Loon Survey and Management Report

River Areas: Loons have occasionally been seen in both the Little Magalloway River north of the Little Magalloway territory and also in the “Upper Magalloway Pool” – north of the east entrance to Sunday pond in the Magalloway River (Figure 2). We recommend monitoring these areas for the presence/absence of loons throughout the season. 3. Color-Marking Individuals: We recommend the continuation of capture and marking efforts in order to add to and maintain current information on the recruitment, between-year territory, mate switching and estimated minimum survivorship on the Aziscohos Lake loon population. 4. Further Management Issues: We recommend continued monitoring of both nest predation causes, and causes of lowered chick survival on Aziscohos. Current monitoring suggests that raft management efforts are effective to boost hatching success; however, limitations beyond hatch are limiting chick survival, potentially from density dependent factors. LITERATURE CITED De Sorbo C. and D. C. Evers. 2002. Aziscohos Lake Common Loon population survey and management report. 2001 Season & Third Five-Year Monitoring Report, 1997-2001. Unpubl. Rept. to FPL Energy Maine Hydro, Lewiston, Maine for submission to FERC. 65 pp. De Sorbo C. and D. C. Evers. 2001. 2000 Aziscohos Lake Common Loon population survey and management report. BRI-2001-02 Unpubl. Rept. to FPL Energy Maine Hydro, Lewiston, Maine for submission to FERC. 31 pp. Evers, D. C. 2001. Common Loon population studies: Continental mercury patterns and breeding territory philopatry. Ph.D. Dissertation, Univ. Minn., St. Paul. Evers, D. C. 1993. A replicable capture method for adult and juvenile Common loons on their nesting lakes. Pp. 214-220 in L. Morse, S. Stockwell, and M. Pokras (eds.). Proc. 1992 Conf. Loon and its ecosystem. U.S. Fish. Wildl. Serv., Concord, NH. Evers D. C. 2000. Aspects of hydrological impacts on the common loon at Lake Umbagog, 19761999. Unpubl. Rept. submitted to US Fish Wildl. Serv., Concord, NH. Evers, D. C., J. D. Kaplan, P. S. Reaman, J. D. Paruk, and P. R. Phifer. 2000. Demographic characteristics of the common loon in the Upper Great Lakes. Pp.78-90 in J. W. McIntyre and D. C. Evers (eds.). Loons: Old history and new findings. Proc. of a symposium from the 1997 meeting, American Ornithologists’ Union. North American Loon Fund, Holderness, NH. Fair, J. 1986. Aziscohos Lake 1986 common loon population survey results and management plan. Unpubl. Rept. to Androscoggin Reservoir Co, Lewiston, ME. for submission to FERC. 17 pp.

19

2003 Aziscohos Lake Common Loon Survey and Management Report

Fair, J. 1990. 1990 Aziscohos Lake Loon Population Survey and Management Report. Unpubl. rep. to Androscoggin Reservoir Co., Lewiston, ME for submission to F.E.R.C. 9 pp. Fair, J. 1992. Cover for loon rafts to obstruct avian depredation. N. American Loon Conf. Proc. Pp. 235. U.S. Fish Wildl. Serv. Concord, NH. Fair, J. 1992a. Common loon nesting success and productivity with regard to lake level fluctuations and management plan implementation on Aziscohos Lake (F.E.R.C. project no. 4026): Fiveyear progress rep. 1987-1991. Unpubl. Rept. to Androscoggin Reservoir Co. Lewiston, ME for Submission to FERC 42pp. Fair, J. 1997b. Common loon reproductive success and productivity on Aziscohos Lake with regard to lake level fluctuations and management plan implementation: Second five-year monitoring report, 1992-1996. Unpubl. rep. submitted to Androscoggin Reservoir Co, Lewiston, ME for submission to FERC. 44 pp. Fair, J. 1999. 1998 Aziscohos Lake Loon Population Survey and Management Report. Unpubl. Rept. to Androscoggin Reservoir Co., Lewiston, ME for submission to F.E.R.C. 12 pp. Fair J. and B. McCoy Poirier 1992. Managing for Common Loons on Hydroelectric Project Reservoirs in Northern New England. Pp. 221 in L. Morse, S. Stockwell and M. Pokras (eds.). 1992 N. American Loon Conf. Proc. U.S. Fish Wildl. Svc. Concord, NH. Kenow, K. P., Pers. com. U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, WI. Kenow, K. P., M. W. Meyer, D. C. Evers, D. C. Douglas and J. Hines. 2002. Use of Satellite Telemetry to Identify Common Loon Migration Routes, Staging Areas and Wintering Range. Waterbirds. 25 (4): 449-458. McIntyre, J. 1988. The Common Loon: Spirit of northern lakes. Univ. Minn. Press, Minneapolis, MN 228 pp. Merrie, T. D. H. 1996. Breeding success of raft-nesting divers in Scotland. Brit. Birds 89:306-307. Newton I. 1992. Lifetime reproduction in birds. Academic Press, NY. Savoy, L., and D.C. Evers. 2003 (In prep). 2002 Mooselookmeguntic Lake Common Loon population survey and management report. Unpubl. Rept. to FPL Energy Maine Hydro, Lewiston, Maine for submission to FERC. Savoy, L., O. Lane, and D.C. Evers. 2002. 2002 Richardson Lake Common Loon population survey and management report. Unpubl. Rept. to FPL Energy Maine Hydro, Lewiston, Maine for submission to FERC. 32pp. Taylor, K. Pers. com. Senior Biologist, Loon Preservation Committee, Moultonboro, NH. 20

2003 Aziscohos Lake Common Loon Survey and Management Report

Taylor, K. and H. Vogel. 2000. Population status of the common loon in New Hampshire. in J. McIntyre and D.C. Evers (eds.). Loons: Old history and new findings. Proc. N. American Loon Fund, Meridith, NH. Taylor, K and H. Vogel (In Prep). Summary of Loon Preservation Committee Research and Management Activities for the 2001 Field Season. Unpubl. Rept. Moultonboro, NH. Yates D., L. Savoy, and D.C. Evers. 2002. 2002 Flagstaff Lake Common Loon population survey and management report. BRI-2001-03 Unpubl. Rept. to FPL Energy Maine Hydro, Lewiston, Maine for submission to FERC. 43 pp.

21

2003 Aziscohos Lake Common Loon Survey and Management Report

Figure 1: Rangeley Lakes Study Area

22

2003 Aziscohos Lake Common Loon Survey and Management Report

Figure 2: Distribution of Common Loon territories on Aziscohos Lake, 2003

23

2003 Aziscohos Lake Common Loon Survey and Management Report

Figure 3: Territorial habitat quality map for Common Loons on Aziscohos Lake based on the number of chicks fledged/territory, 1987-2003.

24

2003 Aziscohos Lake Common Loon Survey and Management Report

Figure 4: Daily Reservoir Water Level for Aziscohos Lake (May 1 – August 15, 2003) 1519.00

1518.00

Elevation in Ft ABove Sea Level

1517.00

1516.00

1515.00

1514.00

1513.00

1512.00

1511.00

1510.00

1509.00 5/1

5/8

5/15

5/22

5/29

6/5

6/12

6/19

6/26

7/3

7/10

7/17

7/24

7/31

8/7

8/14

Date 2003

25

2003 Aziscohos Lake Common Loon Survey and Management Report

1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 21

1 1 0 1 1 1 1 1 1 0 0 1 0 0 0 0 1 1 1 1 0 0 13

1 1 0 1 1 1 1 1 1 0 0 1 0 0 0 0 1 1 1 1 0 0 14

0 1 0 0 2 1 2 2 2 0 0 0 0 0 0 0 0 2 2 0 0 0 14

0 0 0 0 1 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 4

0 1 0 0 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 8

2 2 ? 2 2 2 2 2 2 ~ ~ 2 ~ ~ ~ ~ 2 2 2 2 ~ ~ n/a

I ~ U MP ~ ~ ~ ~ ~ ~ ~ I ~ ~ ~ ~ U ~ ~ U ~ ~ n/a

Explanation of Table Characters

M = Mammalian Predation

* = see individual territory for specific details

A = Avian Predation

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ n/a

~ = N/A

I = Increase in Water Level

U = information unknown

D = Decrease in Water Level UP = Unknown U = Unknown Predation

1? = at least one egg, unconfirmed 2nd

Total Pop (Adults+Chicks (F)+Imm)

Cause of Nest Failure #2*

Cause of Nest Failure #1*

No. Eggs in Nest. N1,N2

Successful Pairs (>/= 1 Chick hatched)

No. Chicks in August (F)

Total Chicks Hatched on Terr. (H)

Total No. Nesting Attempts (eggs laid)

Nesting Pairs (NP)

Territory Little Magalloway Sunday Pond Twin Brook Bosebuck Camo Camp Raven Hurricane Hammel Brook Buck Mountain Yukon Big Brook Meadow Brook North Hammond South Hammond Tiger Gray Aldrich Brook Cold Brook Emery’s Misery Grove Beaver Brook Beaver Island Dam FINAL TOTALS

Territorial Pairs (TP)

Appendix 1: Territory-Specific Productivity Summary (Year 2003 Season). For all recognized territorial pairs on Aziscohos Lake in 2003.

2 2 2 2 3 2 3 3 3 2 0 2 2 2 2 2 2 2 2 2 0 2 44

AB = Abandonment for Unknown Cause R = Egg thought to have rolled out of nest HD = Human Disturbance Intr = Intrusion MT = Mortality of adult

26

2003 Aziscohos Lake Common Loon Survey and Management Report

Appendix 2: NESTING SUMMARY: RAFTS VS. NATURAL SITES For all recognized territorial pairs on Aziscohos Lake in 2003.

12 15 13 1 3 5 4 16 4 6 0 9 2 16 4 2 4 16 2 16 0 5 ~

0 16 7 0 2 3 1 8 2 1 0 0 1 17 3 1 4 17 0 15 0 5 103

0 1 1 0 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 0 1 17

~ 1 0 ~ 1 1 1 1 1 ~ ~ ~ 0 0 0 0 1 1 0 1 ~ 0 9

~ 1 ~ ~ 2 1 2 2 2 ~ ~ ~ ~ ~ ~ ~ 0 2 ~ 0 ~ ~ 12

No. Chicks Fledging from Rafts

No. Chicks Hatched from Rafts

No. Nesting Attempts on Rafts

0 ~ 0 0 ~ ~ ~ ~ ~ ~ ~ 0 ~ ~ ~ ~ ~ ~ 0 ~ ~ ~ 0

2003

No. Rafts Floated

0 ~ 0 0 ~ ~ ~ ~ ~ ~ ~ 0 ~ ~ ~ ~ ~ ~ 2 ~ ~ ~ 2

No. Nesting Attempts Raft Used

1 0 0 1 0 0 0 0 0 ~ 0 1 0 0 0 0 0 0 1 0 0 0 4

No.Years Raft Floated on Territory

No. Chick Fledged From Nat. Sites

17 16 16 17 3 10 17 17 11 15 4 17 6 17 16 5 16 17 5 17 4 17 280

87-02

No. Chicks Hatched From Nat. Sites

Little Magalloway Sunday Pond Twin Brook Bosebuck Camo Camp Raven Hurricane Hammel Brook Buck Mountain Big Brook Yukon Meadow Brook North Hammond South Hammond Tiger Gray Aldrich Brook Cold Brook Emery' s Misery Grove Beaver Brook Beaver Island Dam FINAL TOTALS

Raft Sites

No. Nesting Attempts on Natural Sites

Number Territory Years^^

Natural Sites 2003

~ 0 ~ ~ 1 0 1 1 1 ~ ~ ~ ~ ~ ~ ~ 0 0 ~ 0 ~ ~ 4

Explanation of Table Characters * = see individual territory details ~ = N/A ^^ = Territory years does not include 1986 (due to 1985 dam operations).

27

2003 Aziscohos Lake Common Loon Survey and Management Report

Appendix 3: Nesting Activity Dates in Relation to Water Level. (Year 2003 Nesting Season) Territory Beaver Brook Bosebuck Buck Mountain Camo Camp Cold Brook Emery’s Misery Grove Hammel Brook Hurricane Little Magalloway Meadow Brook Raven Sunday Pond

Nesting Onset Window Nest 1 Nest 2 5/29 - 6/6 (R) 1516.75 – 1516.75 7/22 - 7/29 (N) 1515.95 – 1516.10 6/6 - 6/11 (R) 1516.75 – 1516.95 6/11-6/20 (R) 1516.95 – 1518.25 5/27 – 6/6 (R) 1516.70 – 1516.75 6/6 – 6/12 (R) 1516.75 – 1516.95 6/20 - 6/26 (N) 1518.25 – 1518.05 5/28 – 6/4 (R) 1516.75 – 1516.70 6/11 – 6/20 (R) 1516.95 – 1518.25 6/4 – 6/5 (N) 1516.70 – 1516.65 6/6 – 6/12 (N) 1516.75 – 1516.95 5/28 – 6/4 (R) 1516.75 – 1516.70 6/4 - 6/6 (R) 1516.70 – 1516.75

Hatch Window Nest 1 Nest 2 -

-

7/3 - 7/21 1517.25 – 1515.85 7/14 – 7/21 1516.25 – 1515.85 -

-

7/3 - 7/21 1517.25 – 1515.85 7/3-7/21 1517.25 – 1515.85 6/26 – 7/3 1518.05 – 1517.25 7/3 – 7/21 1517.25 – 1515.85 -

-

7/22 - 7/29 1515.95 – 1516.10 7/4 – 7/21 1517.50 – 1515.85

Nest Failure Window Nest 1 Nest 2 7/3 – 7/21 1517.25 – 1515.85 7/29 – 8/6 1516.10 – 1515.90 -

-

-

-

-

-

-

6/19 – 6/20 1518.20 – 1518.25 -

-

-

-

-

-

-

-

-

-

-

-

-

-

6/11 – 6/20 1516.95 – 1518.25 6/12 - 6/19 1516.95 – 1518.20 -

-

-

-

-

All windows (Onset, Hatch, Nest Failure) are defined by survey visits in combination with site evidence and obvious weather events. They do not necessarily reflect actual survey dates. (R) = Raft was used for nesting by loons. (N) = Natural nest site was used for nesting by loons. Water levels given represent lake surface elevation in feet above mean sea level (USGS) = Aziscohos Dam gauge reading + 985.3. Full Pond = 1520.30 (USGS) – 535.00 gauge.

28

2003 Aziscohos Lake Common Loon Survey and Management Report

Appendix 4: DEFINITION OF TERMS9 Artificial nesting island – A man-made, floating platform for use as an alternate nesting site for common loons as described by the New Hampshire Loon Preservation Committee (LPC)(Fair 1989) and in some cases adapted to prevent avian egg predation through the addition of a cover described by Fair (1992). Artificial nesting islands were first developed and employed as a common loon research tool by McIntyre (1977) in a different form, later improved for management use by LPC. The term “raft” is synonymous with “artificial nesting island” in this report. Avian guard – A camouflage mesh cover that is attached to artificial nesting islands with the intent of minimizing the visibility of the nest and eggs from avian predators and boat traffic. Between-year territory fidelity – The return of an established territory holder to its previously occupied territory. Breeding Adults – Established territory holders, and those with transitional territories that attempted breeding Buffer Population – Encompasses non-territory holders and those with transitional territories that are not breeding Chick survival – Number of loon chicks fledged divided by the number of loon chicks hatched; often expressed (x 100) as a percentage. Chicks fledged – Number of loon chicks to survive past eight weeks of age were assumed to have fledged. Chicks hatched – Number of chicks hatched completely out of their eggs, not necessarily departing from the nest. Established Territory – Paired adults found on territory for at least three consecutive weeks for three consecutive years Estimated minimum survivorship – The known rate of return for adult loons during the breeding season. Fledge rate – Number of chicks fledged divided by either the number of nesting pairs (F/NP) or territorial pairs (F/TP). Also referred to in this report as “fledging success.” F/NP is a representation of the total number of chicks fledged relative to pairs that attempted to nest, F/TP is a representation of the number of chicks fledged relative to all of the territorial pairs within a given subpopulation – including those territorial pairs that did not nest. Hatch rate – Number of chicks hatched divided by the number of nesting pairs (H/NP) or territorial pairs (H/TP) of a given or study-area population. H/NP is a representation of the total number of 9

Terms and definitions are taken from Fair (1992a) and Evers (2001).

29

2003 Aziscohos Lake Common Loon Survey and Management Report

chicks hatched relative to pairs that attempted to nest (also referred to as “hatching success”), H/TP is a representation of the number of chicks fledged relative to all of the territorial pairs within a given population – including those territorial pairs that did not nest. Use of hatch rates in comparisons between populations or time periods allows comparison of productivity between lakes and populations prior to effects of chick mortality. Hatch window – The time, often expressed by a “window” of dates, when an egg(s) hatches. Individual performance – Tracking the reproductive success of marked individuals over time. Long-term productivity – a measure of productivity taking into consideration the number of years the territory has existed or has been monitored. Calculated by dividing the number of chicks hatched divided by the number of years during which the parameter was measured. This measure is analyzed by territory and nest site selection in Appendix 4. Loon – Common Loon (Gavia immer); no other loon species nested in the study area during the report period. Loon return-year – A measure of loon site fidelity that represents the number of years the loon group in question (M, F, or both) returned as a territorial pair to the territory from which it was originally banded. Every year a banded individual is eligible to return is a potential return-year. Mate fidelity – The known pairing of an adult with the previous years’ mate Mate switching – The known change of mates within or between years Multiple lake territory – Paired adults using two or more lakes during a breeding cycle to provide the required resources. Multiple-lake territories are only those that require flight to access another lake. Natal site fidelity – the known return of an individual banded as a juvenile Nest attempt – Presence or evidence of any loon nest constructed or scraped that contained eggs, evidence of eggs, or constructed on a site where a previous nest contained eggs; this excludes copulatory platforms and nests of uncertain origin. Nest failure – Any nest attempt that fails to completely hatch or at least one egg. Nest Onset – The time, often expressed as a “window” of dates, during which a nesting pair lays eggs in a nest. Nest success – Any nest attempt in which at least one chick completely hatches from its egg. Nesting frequency – Number of nesting pairs divided by the number of territorial pairs in a given population or study area; often expressed (x 100) as a percentage. Nesting frequency is an index of the portion of a population attempting reproduction on a given year or time period. 30

2003 Aziscohos Lake Common Loon Survey and Management Report

Nesting pair (NP) –A territorial loon pair, which undertakes one or more nesting attempts on a given year. All territorial pairs are considered potential nesting pairs. Nesting pairs comprise a subset of territorial pairs. Nesting season – That part of the year encompassing early reproductive behavior on the breeding grounds through late hatching of chicks. Nest building may begin prior to complete ice-out of aquatic systems in Maine and New Hampshire and hatches may occur as late as mid August in western Maine (Fair unpubl. Data) Nesting season varies from year to year and across latitudes and from lake to lake. Nesting season varies from year to year and across latitudes and from lake to lake. On Aziscohos Lake during this study period, nesting season may be generally defined as May 15 – August 5. Nesting success – The rate of nest success by pairs; number of loon pairs hatching at least one chick divided by total number of pairs exhibiting at least one nesting attempt; usually expressed (x 100) as a percentage. Non-breeding adults – Territorial and non-territory holders (e.g. floaters) that did not breed that year Partial lake territory –Paired adults sharing a lake with other established territory holders. Common foraging areas used by non-breeding adults frequently exist. Production – The absolute number of chicks fledged (surviving to migrate) within a given time period by a given loon population. Productivity – The number of fledged chicks divided by the number of territorial pairs in a given population, expressed as number of chicks per territorial pair. Less thorough studies have reported productivity in terms of number of chicks (sometimes young chicks) per known nesting pair, not recognizing non-nesting and unsuccessful pairs, and chick mortality on the breeding lake. Certain ecological studies have reported loon productivity in chicks per water surface area. Productivity here reflects the total population of territorial (potential breeding) pairs, nesting frequency, nesting success, and chick survival, and is therefore a more precise and thorough reflection of the reproduction rate of the entire population. Raft – Artificial nesting island for loons. Raft use by loons – a raft is considered used by loons during any nesting season in which one or more nest attempts are made on that raft; may be expressed for a given study area as number of rafts exhibiting one or more nest attempts divided by number of rafts deployed that year; may be expressed (x 100) as a percentage. Renest – Any nest attempt by a pair subsequent to its original nest attempt on a given year. Successful nest – Any nest attempt resulting in at least one chick hatching completely out of its egg, though it may never depart the nest dish. 31

2003 Aziscohos Lake Common Loon Survey and Management Report

Successful nesting pair (SNP) – A loon pair that hatches at least one loon chick completely out of its egg on a given year, regardless of failures of former nests that year. Territorial pair (TP) – A loon pair which exhibits territorial and paired behavior including territorial defense gestures, male yodeling, and close physical association within a defined territory during the nesting season; all nesting pairs are considered territorial pairs. Not all territorial loon pairs nest every year. Territory – An area of still water used by a bonded pair of common loons for feeding, resting, breeding, nesting, chick rearing that is behaviorally protected against incursion by most other loons (and sometimes waterfowl) for a minimum of 4 weeks. Loon breeding activities were formerly described with reference to loon pairs, about under light of new evidence of infidelity among individuals of loon pairs, the territory has become the more certain and useful unit of reference in describing loon breeding activity and rates. Territories are recognized as being either “established” or “transitional.” Long term monitoring will be necessary in order to classify a territory into one of these territory subgroups. Territorial persistence – The tendency for territorial pair to remain present within their territory throughout the season. Measured by the length of time a pair remains on territory throughout the year. Territory years - The number of years a territory has been surveyed. Used as the denominator of the long-term hatch rate productivity measure. Total production – The total number of loon chicks fledged lakewide during the year of time period described; lakewide production. Transitional territory – Paired adults found on a territory for less than three consecutive weeks and/or less than three consecutive years Whole lake territory – One pair of adults is restricted to one lake for the entire breeding cycle. The territory may or may not encompass the entire lake, however, a second pair is not established.

32

2003 Aziscohos Lake Common Loon Survey and Management Report

Territory nest site maps: Maps are shown in the following section for territories in which pairs nested or built a nest dish in a new location. Map 1. Little Magalloway, Sunday Pond and Bosebuck territory nest site locations, 2003.

Little Magalloway

x Sunday Pond

Bosebuck

x

33

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 2. Twin Brook territory and nest dish (not a nesting pair) location, 2003.

Twin Brook

X dish)

34

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 3. Camo Camp territory nest site location, 2003.

X

Camo Camp

35

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 4: Hurricane and Raven territories nest site locations, 2003.

Raven

Hurricane X

36

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 5: Hammel Brook territories nest site locations, 2003.

Hammel Brook X

37

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 6: Buck Mountain territory nest site location, 2005.

Yukon

Buck Mountain

38

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 7: Meadow Brook territory nest site location, 2003.

Meadow Brook

X

39

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 8: Cold Brook territory nest site location, 2003.

Cold Brook

X

40

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 9: Emery’s Misery and Grove territory nest site locations, 2003. Emery’s Misery

Emerys Misery

X Grove

X

41

2003 Aziscohos Lake Common Loon Survey and Management Report

Map 10: Beaver Brook territory and nest site, 2003.

Beaver Brook

42