On the wild side—November, 2011
by Tina Mitchell
A grating, rapid, buzz-saw-like chorus of kraaaaa, kraaaaa, kraaaa pierces the air over a pinyon-covered ridge. The noisemakers? A group of Clark’s Nutcrackers wandering the area in search of pinyon seeds. Yet another member of the fascinating Corvid family (in the company of crows, ravens, magpies, and jays), a Clark’s Nutcracker has a gray body, stunning black wings accented by white patches, and white edgings on the tail. (Both males and females look alike.) Probably its most striking feature is the long, sturdy, chisel-like beak, adapted for removing seeds from tough, unripe pinecones. This massive tool also permits opportunistic foraging, including probing for insects, catching small vertebrates, and ripping apart carrion. All of this bird’s names revolve around this beak. The Clark’s Nutcracker was first identified in the Columbia River region during the Lewis and Clark Expedition in 1805. (When first spotting this bird, Clark thought it was a woodpecker, given its ability to hammer open pinecones.) The scientific name, Nucifraga columbiana, breaks down to “nut breaker from the Columbia River:” “nucis” (“nut” in Latin) and “frango” (to break or shatter). The common name honors the leader of that expedition—Captain William Clark—and, again, its nut-cracking skills.
Although pinyon nuts constitute a vast amount of a nutcracker’s diet, it is also a generalist. If the pinyon seed crop fails, they’ll turn to cones of other conifers, such as limber, ponderosa, and bristlecone pines. A number of research studies have documented the highly developed spatial memories of these birds, such that they re-locate their seed caches based on relationships to large objects such as rocks, logs, or other distinctive, sizable objects in the area. But as generalists, they will also eat berries; insects such as beetles, ants, and grasshoppers; nestling birds and eggs; small mammals—and even unattended picnic delicacies set out by unsuspecting humans. You might see them every now and then at a suet feeder or a heated birdbath in the dead of winter, but they tend not to be regular seed feeder visitors.
These days, Colorado has the largest segment of the continent’s population of Clark’s Nutcrackers—20%. Wyoming and Utah host a mere 13% each, and California comes in a distant 4th place with a measly 10%. Ironically, this bird often lives near treeline on the windy peaks of the western U.S., far from human contact. Yet where it does encounter people, it seems quite fearless, striding about in picnic grounds and scenic-view parking lots, looking for handouts. If you’ve ever stopped at a turnout in Rocky Mountain National Park, you’ve most likely been solicited by these beautiful, bold beggars.
Because the birds rely extensively on pinyon seeds, the pinyon/juniper habitat holds special importance for them. In the late summer and fall, they travel from high-altitude breeding grounds down to pinyon/juniper areas such as those in our area. They collect large quantities of pinyon seeds in their throats (actually, in a structure called the sublingual pouch, found under the tongue). The birds then store these seeds in underground caches back up at altitude—often on south-facing slopes, which will be clear of snow earlier than other areas. This way, during the breeding season, they have large stores of seeds available to feed their young.
Clark’s Nutcrackers don’t breed until their second year. They begin breeding in very early spring, when deep snows render the breeding grounds inaccessible to most predators. Typically nesting in high-altitude confers, they seek out nest sites that provide shelter from the howling winds of March and April. The young often hatch while snow still covers the ground, but the adults can still track down their stores of pinyon nuts. An adult uses its hefty beak to dig into the snow at a cache site by sweeping its beak from side to side—kind of like a very pointy broom. Another adaptation to early nesting in cold, snowy areas allows both the male and female to brood the eggs and young: Both sexes develop a brood patch—an area of skin on the breast with many surface blood vessels that helps to keep eggs warm during incubation. (In most songbirds, only the females have a brood patch.) In these cold temperatures, the eggs and featherless young cannot be left exposed to the elements. Thus, the male can share the incubation duties with the female. The female can then retrieve seeds from her stores to supplement those from her mate’s caches. After 18 days, the nestlings hatch, remaining in the nest for approximately 20 days before fledging. The fledglings travel with the family group until late summer, learning to find and harvest conifer seeds of all types. Even after that, the first-year non-breeding juveniles often wander the countryside in loose, gangly flocks while the older birds pair up for next year’s breeding season.
Starting in mid-July, you’ll likely begin to hear the calls of these noisy pinecone harvesters moving around our area, hoping for good pinyon crops to provide a harvest for next year’s high-altitude young.
To learn a bit more about these birds and hear a clip of its voice, check out this page.