Natural History of Our Common Birds: Amazing Facts You (and Your Kids) Should Know Dark-‐Eyed Junco Field marks: outer white tail feathers and pinkish bill are distinct, Oregon Juncos have dark gray to black hood with the males having a slightly darker hood than the females Habitat: coniferous stories, woodlands, backyards, roadsides, etc Diet: omnivores eating primarily seeds and insects Range: Dark-‐eyed Juncos are located through the US, in our region year-‐round. Some populations in the East breed in Canada. Breeding information: female builds the nest and incubates the eggs but males help with nestling care and feeding; 3-‐6 egg clutches and 1-‐3 broods per breeding season Fun facts: -‐One of the most abundant birds of North America -‐Estimated 630 million individuals in North America -‐In sparrow family -‐Dark-‐eyed Juncos are one species but there are actually 6 distinct groups in NA. They are considered 1 species because they still interbreed and are genetically very closely related -‐Study in Appalachian mountains of Virginia – adding testosterone to male dark-‐eyed juncos made the birds hold bigger territories and sing more frequently but also meant that the males gave less parental care and bred with multiple females -‐The breeding birds in the Sierra belong to the Oregon Junco subspecies. -‐John Audubon described Dark-‐eyed Juncos meat as “…extremely delicate and juicy”
Common Raven Field marks: all black, much bigger than a crow, wedge shaped tails and longer wing fingers than a crow’s, very conspicuous, large variety of calls, thicker bill than crow Habitat: do well around humans, desert, sea coast, deciduous and evergreen tree forests, sagebrush, tundra and grasslands Range: western North America, and all of Canada. Not really east of Rockies, although there is a small population in Texas and in the Appalachian mountains Breeding information: It is not known if Ravens mate for life because they are very secretive. Breeding pairs hold large territories and regularly return to the same nest which is built by the female and made of sticks usually located on a hill or Cliffside. Fun facts: -‐ Ravens are among the most intelligent of all birds – sometimes working together to raid seabird nesting colonies and stealing eggs from other songbird species’ nests
-‐ Although commonly mistaken for the American Crow, the Common Raven represents a completely different species and can be identified by its bigger size, rounded tail during flight and larger beak -‐ Ravens are known for their acrobatic performances they often show off in the air, doing turns and dives and sometimes even playing “catch” by constantly dropping and catching a stick -‐ The first Common Raven in Yosemite wasn’t reported until 1966. -‐ Ravens are scavengers! They are limited to carcasses which have already been torn open because they are not able to tear skin using their beak. -‐ Ravens have a complicated relationship with American Crows and seem to avoid each other by using different areas. -‐ Ravens without mates usually hang out in large groups so that they are better able to over-‐take or overwhelm a pair defending a food source within their territory.
American Crow Field marks: all black, smaller than a Raven, very straight black beak, shorter tail than Raven Habitat: Crows thrive around people, and usually do not overlap with Ravens for habitat, usually found in fields, woodlands and forests and commonly hang out near garbage dumps and other human wastelands Range: year-‐round over most of North America with some exceptions in the southwest Breeding information: both males and females help to build nests and sometimes second year birds from the same pair will assist as well. Fun facts: -‐ American Crows sometimes change eye color from blue/blue gray to brown as the bird matures-‐ the reason for this change is not yet known -‐ In a study in Seattle, scientists found that Crows are able to recognize faces. Scientists captured seven Crows while wearing masks. The birds recognized the masks and would dive and “caw” at the masks after the capture. Soon, more than just the seven captured Crows were aware of and recognizing the masks – the Crows had communicated the information of the masks to the greater population. When the researchers walked around campus without a mask, the Crows did not show any reaction. -‐ They have been observed using cars to crush the shells of nuts they are eating, specifically using traffic signals to make sure they are safe when they fly down to pick up their nut
Steller’s Jay Field marks: Although “blue” in coloration and “Jay” by family, Steller’s Jays represent a completely different species from the Blue Jay which is found only east of the Rocky Mountains. They are distinctive because of the large crest on their head. Habitat: Evergreen forests west of the Rockies usually between 3,000 and 10,000 feet in elevation Range: Western North America and Canada, mid to high elevation
Breeding information: Steller’s Jays and Blue Jays are the only New World (Americas) Jays that use mud to build their nests, females do most of nest building and incubating but males accompany them. Their clutch size is 4-‐5 eggs with incubation usually taking 16 days Fun facts: -‐ Steller’s Jays are habitual nest robbers, like many other Jay species, and have been seen robbing Junco and other song bird species’ nests of eggs and nestlings -‐ Steller’s Jays are named for Georg Steller, a Russian who is given credit for discovering them as well as the Steller’s Sea Lion and Steller’s Sea Eagle
Red-‐tailed Hawk Field marks: Most common bird of prey, distinguished by rusty red tail which is highly visible as they fly overhead Habitat: all types of open country, usually soaring over meadows Range: Red-‐tailed Hawks can be found year-‐round in all of North America, lots of RTHA migrate to California during the winter which causes their populations to swell Breeding information: nests are usually re-‐used year after year and males and females help to incubate the 2-‐4 eggs Fun facts: -‐ Red-‐tailed Hawks are the most common hawk in all of North America -‐ They are distinguished by their reddish-‐orange tail seen in soaring flight -‐ Males and females have been observed locking talons while diving toward the ground during a courtship ritual; pairs mate for life and maintain pair bonds all year -‐ three quarters of their diet is made up of rodents, the rest of the diet being made of snakes and smaller birds
American Robin Field marks: grayish blue back, white ring around the eye, rusty red bellies, the male has more vibrant colors than females Habitat: generalist – forests, woodlands, gardens, parks Range: American Robins can be found year-‐round in North America; however many birds from Canada do migrate down to the States for the winter, boosting populations Breeding information: 3-‐5 eggs and 1-‐3 broods, females, with some help from males, build very sturdy nests which are lined with mud and grass and usually are found in conifer trees Fun facts: -‐ Robins are thought to be the first birds to migrate back after winter but actually, many winter in the breeding grounds but spend their time roosting in trees and not foraging on the ground, where we are used to seeing them -‐ Robins locate worms using their eyes not their ears -‐ American Robins were hunted for their meat in the 1800s and Audubon described them as being “bagged by the hundreds”
-‐ American Robins were very susceptible to DDT poisoning because they eat worms which contained high levels of DDT from the grass and vegetation found in people’s yards – earth worms are able to sequester great amounts of DDT and were being killed in great numbers in Michigan – this was first reported in Rachel Carson’s Silent Spring
Turkey Vulture Field marks: large black birds, usually seen soaring and making a V with their wings, red, feather-‐less head, large and long “fingers” can be observed on the outside of the wings when seen soaring overhead, the under-‐feathers of the wings are paler in comparison to the dark flight feathers. The Turkey Vulture soars but also teeters in flight… a characteristic which can be used to identify the species in the air Habitat: open areas, near dead animals, roadside Range: winter in southern US and breed all over US Breeding information: 1-‐3 eggs, 1 brood per year. They do not build full nests but scrape out an area in leaf litter or rotting wood and will use the same spot year after year Fun facts: -‐Turkey Vultures are mostly immune to Botulism, salmonella and cholera -‐Turkey Vultures are scavengers and usually feed on recently killed mammals, usually using their great sense of smell and their eyes to locate the carrion. -‐The sink rate is the rate at which a soaring bird loses altitude; Turkey Vultures have a sink rate which is smaller than that of Black Vultures which could explain for the distribution of the birds. Turkey Vultures are able to live in cooler climates where the thermals are not as warm whereas Black Vultures are forced to live in warmer climates where the thermals are warmer due to their higher sink rate -‐Indian Vulture Crisis-‐ historically, huge vulture populations helped to clean up carcasses including cows which are not eaten by humans for religious reasons. In the 1990s vulture populations were noticed to be declining and it was determined that the anti-‐inflammatory drug diclofenac was responsible for the change. Diclofenac was given to cows in order to prolong dairy production and all species of vultures in India were highly susceptible to the drug. Since this link was discovered, the anti-‐inflammatory drug has been switched to something which does not negatively affect vultures, however, the populations have seriously declined. As a result of the small vulture populations, the wild dog population has increased which has presented the human population with huge problems of disease including rabies. On its own, India suffers have of all deaths associated with rabies in the world.
Acorn Woodpecker Field marks: loud and raucous, with a black head and red cap and white circle around their beak. They are medium-‐sized woodpeckers. Habitat: Oak and mixed Oak – Conifer forests, very tolerant of humans Range: Found on the Southwest and West coast
Breeding information: Acorn woodpeckers breed cooperatively with some groups consisting of up to 15 individuals which are usually all related: parents, siblings and cousins stay together for a number of years, helping to defend territories and granaries where acorns are stored. In each group, up to four males will mate with one female and all eggs are incubated in a single nest. Fun facts: -‐Acorn Woodpeckers are hoarders! Due to the seasonality of their diet, these woodpeckers have evolved storage and hoarding techniques. They usually select one or two storage sites near the center of the territory and can store as many as 50,000 acorns in one location! These are called granaries. The trees usually do not benefit from this relationship because the acorns are not stored in places where they might germinate. Clark’s nutcrackers DO benefit whitebark pines due to their hoarding because they store the pine nuts in location where they are able to germinate. In fact, it is said that whitebarks actually depend on Clark’s nutcrackers for their reproduction -‐Acorn Woodpeckers have been known to attack squirrels and other birds who try to raid their acorn stashes -‐Acorn Woodpeckers defend their territory against other Acorn Woodpeckers as well as other species which might pose a threat including squirrels, Lewis’s Woodpecker and European Starlings
Western Scrub Jay
Field marks: blue head, wings and tail with a gray patch on the back. Distinguished from the Blue Jay by lack of crest on head and range, distinguished from Steller’s Jay by lack of crest on head and distinct coloring Habitat: Usually found in lower and drier habitats than Steller’s Jays; prefers open country, oak woodlands, chaparral, some evergreen forests and is happy near developed areas Range: South to mid-‐latitudinal Western US Breeding information: both male and female help with nest building and young rearing, mating pairs stay together throughout the year Fun facts: -‐Scrub Jays in this area eat Acorns in the non-‐breeding season and have evolved a thicker beak than the Scrub Jays which rely on Pinyon pine nuts for food during the non-‐breeding season -‐The Florida Scrub Jay, a separate species which looks almost identical to the Western Scrub Jay, is a communal breeder -‐Western Scrub Jays sometimes land on the backs of mule deer and remove parasites and insects such as ticks; the mule deer welcome this service and usually prick up their ears to give the Jays access to their fur -‐Scrub Jays sometimes steal acorns from the granaries of the Acorn Woodpeckers and stash the seeds in fertile locations where they are frequently forgotten by the Scrub Jay and thus are able to germinate. Sources: Lukas, David. Sierra Nevada Birds: A Compact Field Guide Companion www.allaboutbirds.org (Cornell Lab of Ornithology) Dobkin, David S, Ehrlich, Paul S and Wheye, Darryl. The Birder’s Handbook: A Field Guide to the Natural History of North American Birds Wikipedia
