Blue Jay

Identification

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). Consistent with Bergmann's rule, jays from Connecticut averaged 92.4 g (3.26 oz) in mass, while jays from warmer southern Florida averaged 73.7 g (2.60 oz). 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 will be fully raised. When frightened, the crest bristles outwards, brushlike. When the bird is feeding among other jays or resting, the crest is flattened on the head.<p>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 almost identical, but the male is slightly larger. The black plumage on its nape, face, and throat varies extensively between individuals; it is believed to assist in recognition between individuals.<p>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 because the structure is destroyed. The actual pigment in its feathers is melanin. This is referred to as structural coloration.

Taxonomy

The blue jay was first described as Pica glandaria cærulea cristata in English naturalist Mark Catesby's 1731 publication of Natural History of Carolina, Florida, and the Bahamas. It was later described as Corvus cristatus in Carl Linnaeus' 1758 edition of Systema Naturae. In the 19th century, the jay was described by French ornithologist Charles Lucien Bonaparte in 1838 as Cyanocorax cristatus in A geographical and comparative list of the birds of Europe and North America, and given its modern scientific name Cyanocitta cristata by Hugh Edwin Strickland in 1845. The genus name Cyanocitta derives from the Greek words kyaneos (blue) and the kitta and kissa (chattering bird, jay), and the term "blue chatterer" refers to the bright blue plumage of the head, nape, back, and tail of the bird. The specific name cristata (crested, tufted) derives from Latin referring to the prominent blue crest of the jay.

Scientific name

Cyanocitta cristata

Authority

(Linnaeus, 1758)

Order

Passeriformes

Family

Corvidae

Genus

Cyanocitta

Range and habitat

The blue jay occurs from southern Canada (including the southern areas of provinces from Alberta eastward to Quebec and throughout the Atlantic provinces) and throughout the eastern and central United States 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 (C. stelleri) begins, generally in the eastern foothills of the Rocky Mountains. Recently, the range of the blue jay has extended northwestwards so that it is now a rare but regularly seen winter visitor along the northern US and southern Canadian Pacific Coast. As the two species' ranges now overlap, C. cristata may sometimes hybridize with Steller's jay. The increase in trees throughout the Great Plains during the past century due to fire suppression and tree planting facilitated the western range expansion of the blue jay as well as range expansions of many other species of birds. From 1966 to 2015, the Blue Jay experienced a population decline along the Atlantic coast, but a greater than 1.5% annual population increase throughout the northern part of its range, including Labrador, Nova Scotia, southern Quebec, and southern Manitoba.<p>The northernmost subspecies C. c. bromia is migratory, subject to necessity. It may withdraw several hundred kilometers south in the northernmost parts of its range. Thousands of blue jays have been observed to migrate in flocks along the Great Lakes and Atlantic coasts. It migrates during the daytime, in loose flocks of 5 to 250 birds. Much about their migratory behavior remains a mystery. Some are present throughout winter in all parts of their range. Young jays may be more likely to migrate than adults, but many adults also migrate. Some individual jays migrate south one year, stay north the next winter, and then migrate south again the next year. To date, no one has concretely worked out why they migrate when they do. Likely, it is related to weather conditions and how abundant the winter food sources are, which can determine whether other northern birds will move south.<p>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.

Migration

Complete migrants

Behavior

Migration pattern: Complete migrants.

Conservation

Population trend: stable.

Population trend

stable