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Monday, December 23, 2013

Clever Corvids

Common Raven, Corvus corax

Crows, ravens, and jays are members of the Corvidae family, or corvids for short.  Medium to large perching birds with strong bills and feet, and feathers that are predominately black or blue, they are bold, curious creatures, and are found in a wide range of habitats.  

Corvids are known for their high degree of intelligence in the bird world, especially crows and ravens.  Crows have performed as well as monkeys in psychological tests, and most employ intelligence in their daily routines, such as dropping nuts onto hard surfaces (like roads) to crack them.  Ravens can recognize groups of different sizes up to seven, and often show problem-solving insight when posed with an intriguing new task.  

Corvids are very social birds, with most living in extended family groups year-round.  Groups give the birds an ability to guard one another, and those posing as sentries can warn other birds and wildlife when predators such as hawks and owls are near, sometimes mobbing them and chasing them away.  While corvids are noisy birds with loud, often screeching calls, they are also excellent mimics of other birds, and those in captivity have been shown to mimic even human speech. During the winter, when food can be scarce and the weather harsh, corvids aggregate in large groups at abundant food sources and roost together to stay warm at night.  

American Crow, Corvus brachyrhynchos

Found primarily east of the Balcones Escarpment in our area, the American Crow (Corvus brachyrhynchos) is an all black, thick-necked bird with a straight, heavy bill and a short tail that is squared off or rounded at the end.  Their loud cawing gives them away, and many times you will hear them before you see them.  Highly adaptable, they will live in any open space that offers trees for perching and a reliable source of food.  The Common Raven (Corvus corax) is a very similar-looking all black bird, larger but more slender, and with a wedge-shaped tail.  It is found mainly in the Edwards Plateau west of the escarpment and in far West Texas.  An acrobatic flier, one adult was observed flying upside-down for more than a half-mile, and young birds are often seen dropping sticks and diving to catch them in mid-air.  

Western Scrub-Jay, Aphelocoma californica
Blue Jay, Cyanocitta cristata

While there are two species of jays in our area, they overlap only slightly in range.  The Western-Scrub Jay (Aphelocoma californica) prefers the juniper-oak woodlands of the Texas Hill Country while the Blue Jay (Cyanocitta cristata) inhabits the prairies and grasslands in the eastern part of town.  Gorgeous azure blue above with a slate gray back and light gray breast, Western Scrub-Jays lack the head crest and black barring with white patches on the wings that distinguish them from the Blue Jays.  Both species of jays have a mischievous streak, stealing other birds’ cached food and chasing off smaller birds to steal sunflower seeds and peanuts at feeders.   

Green Jay, Cyanocorax ymcas, this common resident of deep south Texas hasn't made it to Austin - yet.

In the wild, corvids are long-lived birds, often reaching over 15 years of age.  During their lives they clearly learn to act intelligently, and we have yet to determine how intelligence might be distinguished from instinct.  But the more we observe and record their behaviors, the more we can appreciate and enjoy these clever corvids!