Note: this post, while published, is a work in progress, as are all posts in this series, My Photo Life List. My goal is to photograph every species of bird that is seen on a regular basis here in Michigan, working from a list compiled by the Michigan chapter of the Audubon Society. This will be a lifelong project, that I began in January of 2013, and as I shoot better photos of this, or any other species, I will update the post for that species with better photos when I can. While this series is not intended to be a field guide per se, my minimum standard for the photos in this series is that one has to be able to make a positive identification of the species in my photos. The information posted here is from either my observations or the Wikipedia, the online free encyclopedia, however, I have personally shot all the photos appearing in this series.
Blue Jay, Cyanocitta cristata
The Blue Jay is a passerine bird in the family Corvidae, native to North America. It is resident through most of eastern and central United States and southern Canada, although western populations may be migratory. It breeds in both deciduous and coniferous forests, and is common near and in residential areas.
The Blue Jay measures 22–30 cm (9–12 in) from bill to tail and weighs 70–100 g (2.5–3.5 oz), with a wingspan of 34–43 cm (13–17 in). There is a pronounced crest on the head, a crown of feathers, which may be raised or lowered according to the bird's mood. When excited or aggressive, the crest may be fully raised. When frightened, the crest bristles outwards, brush-like. When the bird is feeding among other jays or resting, the crest is flattened to the head.
Its plumage is lavender-blue to mid-blue in the crest, back, wings, and tail, and its face is white. The underside is off-white and the neck is collared with black which extends to the sides of the head. The wing primaries and tail are strongly barred with black, sky-blue and white. The bill, legs, and eyes are all black. Males and females are nearly identical, but the male is a little larger.
As with most other blue-hued birds, the Blue Jay's coloration is not derived from pigments but is the result of light interference due to the internal structure of the feathers, if a blue feather is crushed, the blue disappears as the structure is destroyed. This is referred to as structural coloration.
The Blue Jay occurs from southern Canada through the eastern and central USA south to Florida and northeastern Texas. The western edge of the range stops where the arid pine forest and scrub habitat of the closely related Steller's jay begins.
The Blue Jay occupies a variety of habitats within its large range, from the pine woods of Florida to the spruce-fir forests of northern Ontario. It is less abundant in denser forests, preferring mixed woodlands with oaks and beeches. It has expertly adapted to human activity, occurring in parks and residential areas, and can adapt to wholesale deforestation with relative ease if human activity creates other means for the jays to get by.
The Blue Jay is a noisy, bold and aggressive passerine. It is a moderately slow flier (roughly 32–40 km/h (20–25 mi/h)) when unprovoked. It flies with body and tail held level, with slow wing beats. Due to its slow flying speeds, this species makes easy prey for hawks and owls when flying in open areas. Virtually all the raptorial birds sympatric in distribution with the Blue Jay may predate it, especially swift bird-hunting specialists such as the Accipiter hawks. Diverse predators may predate jay eggs and young up to their fledging stage, including tree squirrels, snakes, cats, crows, raccoons, opossums, other jays and possibly many of the same birds of prey who attack adults.
The Blue Jay can be beneficial to other bird species, as it may chase predatory birds, such as hawks and owls, and will scream if it sees a predator within its territory. It has also been known to sound an alarm call when hawks or other dangers are near, and smaller birds often recognize this call and hide themselves away accordingly. It may occasionally impersonate the calls of raptors, especially those of the Red-tailed and Red-shouldered Hawks, possibly to test if a hawk is in the vicinity, though also possibly to scare off other birds that may compete for food sources. It may also be aggressive towards humans who come close to its nest, and if an owl roosts near the nest during the daytime the Blue Jay mobs it until it takes a new roost. However, Blue Jays have also been known to attack or kill other smaller birds. Jays are very territorial birds, and they will chase others from a feeder for an easier meal. Additionally, the Blue Jay may raid other birds' nests, stealing eggs, chicks, and nests. However, this may not be as common as is typically thought, as only 1% of food matter in one study was compromised by birds. Despite this, other passerines may still mob jays who come within their breeding territories.
Blue Jays, like other corvids, are highly curious and are considered intelligent birds. Young individuals playfully snatch brightly colored or reflective objects, such as bottle caps or pieces of aluminium foil, and carry them around until they lose interest. While not confirmed to have engaged in tool use in the wild, blue jays in captivity have been observed using strips of newspaper as tools to obtain food, while captive fledglings have been observed attempting to open the door to their cages.
Blue Jays have strong black bills which they use for cracking nuts and acorns, usually while holding them with their feet, and for eating corn, grains and seeds. Its food is sought both on the ground and in trees and includes virtually all known types of plant and animal sources, such as acorns and beech mast, weed seeds, grain, fruits and other berries, peanuts, bread, meat, small invertebrates of many types, scraps in town parks, bird-table food and rarely eggs and nestlings. Blue Jays will sometimes cache food, though to what extent differs widely among individuals. Although seemingly contentious in their general behavior, Blue jays are frequently subservient to other medium-sized birds who visit bird-feeders. In Florida, Blue jays were dominated at feeders by Eastern gray squirrels, Florida Scrub-Jays, Common Grackles and Red-headed Woodpeckers, all of which were occasionally observed to aggressively prevent the jays from feeding.
Blue Jays typically form monogamous pair bonds for life. Both sexes build the nest and rear the young, though only the female broods them. The male feeds the female while she is brooding the eggs. There are usually between 3 and 6 (averaging 4 or 5) eggs laid and incubated over 16–18 days. The young fledge usually between 17–21 days after hatching.
After the juveniles fledge, the family travels and forages together until early fall, when the young birds disperse to avoid competition for food during the winter. Sexual maturity is reached after one year of age. Blue jays have been recorded to live for more than 26 years in captivity and one wild jay was found to have been around 17 and a half years old. A more common lifespan for wild birds that survive to adulthood is around 7 years.
Blue Jays can make a large variety of sounds, and individuals may vary perceptibly in their calling style. Like other corvids, they may learn to mimic human speech. Blue Jays can also copy the cries of local hawks so well that it is sometimes difficult to tell which it is. Their voice is typical of most jays in being varied, but the most commonly recognized sound is the alarm call, which is a loud, almost gull-like scream. There is also a high-pitched "jayer-jayer" call that increases in speed as the bird becomes more agitated. This particular call can be easily confused with the chickadee's song because of the slow starting chick-ah-dee-ee. Blue Jays will use these calls to band together to mob potential predators such as hawks and drive them away from the jays' nests.
Blue Jays also have quiet, almost subliminal calls which they use among themselves in proximity. One of the most distinctive calls of this type is often referred to as the "rusty pump" owing to its squeaky resemblance to the sound of an old hand-operated water pump. The Blue Jay (and other corvids) are distinct from most other songbirds for using their call as a song.
On to my photos:
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
Blue Jay, Cyanocitta cristata
This is number 112 in my photo life list, only 238 to go!
That's it for this one, thanks for stopping by!
WordPress.com
No comments:
Post a Comment