Corvids Part VI - Clark's Nutcracker

This is my sixth and final post in my series regarding the Corvids: the Jays specifically. I’ve decided not to include the Mexican Jay, as it is not likely I’d ever see it, even in way-south-central Colorado. Funny, when I look at a small map, Mexico just doesn’t look that far away; all my wishing isn’t going to bring them further up New Mexico, either. (They're really cool birds)

As stated, Jays are several colorful species of passerine, or perching bird. They are somewhat large for songbirds (as passerines are less accurately called) with sturdy, thick bills and strong legs; and they’re loud and every bit as impertinent as their name implies (Jay). Like other corvids, the Jays may even learn to mimic human speech. Jays are omnivores and eat about anything, though nuts and seeds are most important to their diet. However, some members of this diverse family, notably Clark’s Nutcrackers and Pinyon Jays, will undertake substantial movements in search of specific tree seeds. Most members do not migrate though, with the exception, primarly, of the Blue Jay.

Corvid numbers are healthy, in spite of losses to West Nile virus. Many are expanding their territories and in spite of hundreds of years of persecution as pests, clearly show no ill effect on their population. This species has long been known for cleverness but recent studies have shown they have even more intelligence than formerly known; even having the extremely unusual animal ability of recognizing itself in a mirror. Sexes look alike.

Clark's Nutcracker (Nucifraga columbiana) is ash-gray allover, with black and white wings and tail. Central tail feathers are black, outer tail-feathers white. There is a small, white patch at the trailing edges of the wings most visible in flight, on an otherwise black wing. Bill, legs and feet are black. Its primary food source are the seeds of various pines, especiall white pine, found in high altitude, cold climates. It nests early and moves to lower altitudes following the ripening cone crop of various conifers, especially pinyon pine. Nutcrackers also undergo sporadic irruptions into lowland areas…but only once every several years or more.

A bird of the high mountain regions of the American West, the Clark's Nutcracker is specialized for feeding on large pine seeds. Its behavior, annual cycle and even its morphology are closely tied to this diet. Like some other jays, this one has a special pouch for carrying seed long distances. Surplus seed is stored, usually in the ground on exposed slopes, in caches of five to ten seeds spread over a territory of something less than about fifty acres. They store more than they usually need, as protection against theft, but thereby also perpetuating its own food supply…as some of this seed sprouts to become new trees. Seed dispersal by Clark’s Nutcracker has resulted in a commonly occurring tree cluster growth form in 3 of these pines and has altered their genetic population structure in comparison to wind-dispersed pines. This storage behavior is associated with all jays’ remarkable memories; they are able to locate seed caches with remarkable accuracy; even six months later and burried under three feet of snow. When collecting seeds to cache, a bird can store as many as 90 seeds in a pouch behind its tongue. When full, the pouch forms a large bulge at the throat.

The Clark’s Nutcrackers eat much the same diet as other corvids; insects, berries, small animals and eggs…peanuts and suet from bird feeders are a favorite. They are especially adept at extracting food from pinecones by holding the cone in their feet and hacking it open with their strong bills. They locate large grubs in rotten logs in the same way and flip animal dung, again like other corvids, in search of insects.

These birds are monogamous and form long-term pair bonds. Pairs stay together on their territories year round. They begin nesting in late winter; relying on the food they have cached to raise their young. They typically nest in a conifer tree, generally in a fork at the outer branches. Both members of the pair help build the nest, which is a platform of twigs and bark, with a well-insulated cup made of bark strips and grass, with pine needles on top. The Clark's Nutcracker is one of very few members of the crow family where the male incubates the eggs. In jays and crows, taking care of the eggs is for the female only, but the male nutcracker actually develops a brood patch on its chest just like the female and takes his turn keeping the eggs warm while the female goes off to get seeds out of her caches. Almost all juveniles become independent by the time the new seed crop is ripe, making their own caches.

Populations fluctuate, but may be increasing in some areas. Declining pine species in some areas, due to cattle ranching and/or climate change, may lead to reduction in nutcracker numbers.

And again, this jay’s voice is extremely varied and it can produce many different sounds. However, the most frequent call of Clark’s Nutcracker is commonly described as khaaa-khaaa-khaaa or khraa-khraa-khraa, usually in a series of three. Listen here.

Sources:

• http://en.wikipedia.org/wiki/Clark
• http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Clarks_Nutcracker.html
• http://birdweb.org/birdweb/bird_details.aspx?id=314