In the distance, I could see dozens of birds in the trees. Occasionally, white patches flashed from tails and wings as the birds hopped from branch to branch or flew down to the ground. I drew closer and soon realized I was watching two quintessentially western species.
Individual birds were hammering at pine cones held fast with their feet. They were Clark’s Nutcrackers busy at work in pine cone-laden pinyon trees growing along the sides of a small canyon. Higher up, along the rim, scores of raucous Pinyon Jays were moving through the trees and walking about on the boulder-strewn slope, probing the ground with their bills.
Large flocks of Pinyon Jays are a fairly common sight along the South Fork of the Little Colorado River in eastern Arizona. Large numbers of Clark’s Nutcrackers, however, are another matter. I usually see them in mixed-conifer or spruce-fir habitat at much higher elevations. Most often, I come across a single bird giving its raspy grating call while perched atop a limber pine, or small groups flying at treetop level though the forest.
As I watched that September morning, I was struck not only by the sheer number of birds but also by how alike the two species looked in silhouette or profile. In fact, they share many physical and behavioral traits that make them uniquely suited to what they were doing that morning — collecting, transporting, and caching pine seeds.
Many people’s first encounter with Clark’s Nutcracker is at scenic viewpoints or campgrounds in western national parks, where it often hops about looking for food handouts. Its range extends from central British Columbia and western Alberta south through Washington, Oregon, and much of the intermountain west to Arizona and New Mexico. A strikingly handsome bird, it has a whitish gray head and underparts set off by jet-black wings. It has a long, sharply pointed bill, and its short tail and long wings show white patches in flight, making it easy to spot as it flies through the trees.
Clark’s Nutcracker is named for Captain William Clark, of Lewis and Clark fame, who first observed and described it in Idaho during the expedition in 1805. Perhaps watching the bird hacking away at a pine cone, he mistakenly thought it was a new species of woodpecker, an error that was later caught by expedition leader Meriwether Lewis, who correctly put it in the crow family (Corvidae).
Pinyon Jay occurs over a large portion of the interior western United States. It ranges from central Oregon east to western South Dakota and south to Baja California and central New Mexico. Go looking for it, however, and it seems to be one of those birds that you see either dozens of or none at all. This is in part due to the fact that it is very social. It nests in colonies, building a single bulky, well-insulated nest per tree, and lives in large, roving, communal flocks, which at times can number in the hundreds.
There are, however, exceptions to this all-or-nothing rule. I remember once trying to find Pinyon Jay in northern Arizona for a visitor from Minnesota who badly wanted it for a life bird. After searching all afternoon without success, we spotted a bird sitting atop a tree in the distance. It was a lone Pinyon Jay, and, yes, it was perched on a pinyon pine tree.
Unlike its flashy nutcracker cousin, Pinyon Jay is a uniform rather dull blue. Like the nutcracker, it has a prominent, sharply pointed bill. The jay’s generic name Gymnorhinus — composed of gymnos, the Greek word for “naked,” and rhinos, “nose” — refers to the fact that the base of the bill is featherless, an adaptation that allows the bird to probe deep into pitch-laden pine cones. The call of the Pinyon Jay is a loud, quavering queh, queh, which carries great distances and seems to echo through the trees. Perhaps no other call is more strongly associated with western pinyon-juniper woodland.
Dependent on seeds
Both Pinyon Jay and Clark’s Nutcracker are omnivores. They eat a wide range of foods but prefer pine seeds when available. In winter, however, they are almost entirely dependent on the seeds they have collected and cached from the previous autumn. Indeed, both species begin nesting in late winter or early spring, earlier than just about any other North American songbird. They are able to do this because of the energy provided by the hidden seeds; they do not have to wait until other food becomes available in the spring. Other birds — notably woodpeckers, nuthatches, and chickadees — also set food aside for later, but none does it nearly to the same extent. Individual Clark’s Nutcrackers and Pinyon Jays will cache tens of thousands of seeds in thousands of different cache sites in years when seed crops are good.
They do it by thrusting their bills into the ground, depositing a few seeds, and then covering their cache with dirt, pebbles, or even leaf litter. Pinyon Jay primarily stores seeds of the pinyon pine, while Clark’s Nutcracker sets aside the seeds of mostly higher-elevation pine trees. On occasion, large numbers of Clark’s Nutcrackers will move into the lower-elevation pinyon pine forest in search of seeds, as I observed along the South Fork of the Little Colorado River that crisp autumn day.
The relationship between Pinyon Jay, Clark’s Nutcracker, and the pine trees is often described as co-dependent, and it may be driving the evolution of both the trees and the birds. The relationship is mutually beneficial; each has become dependent on the other. In exchange for a reliable source of nutritious food, the jays and nutcrackers perpetuate the pine forest by dispersing and planting the trees’ “wingless” seeds. From forgotten or overlooked seed caches, saplings grow. Consequently, both birds play an important role in re-planting treeless areas in the west.
In the first edition of his Guide to the Birds, David Sibley placed Pinyon Jay and Clark’s Nutcracker together under the heading “Specialized Jays.” Ornithologist Russell P. Balda, Emeritus Regents’ Professor at Northern Arizona University, is one of the leading authorities on the species. He believes that Pinyon Jay may be evolving away, or diverging, from relatives like Mexican Jay and Western Scrub-Jay and converging on the nutcracker. As he puts it: “The Pinyon Jay appears to be a Nutcracker ‘want-to-be.’ ”
Pinyon Jay and Clark’s Nutcracker have evolved a number of physical characteristics that make them superbly adapted to life in the pines. Both have long wings and are powerful flyers. Clark’s Nutcracker in particular is known to make repeated long-distance, high-altitude flights from seed-collecting sites to caching areas that can be up to almost 14 miles (22 km) away.
When cone crops fail
Keep watch! Both Pinyon Jay and Clark’s Nutcracker are known to wander when cone crops fail.
Pinyon Jay may irrupt in all directions: west to central-western and southwestern California; north to northern Idaho, southern Washington, and western Montana; east to Nebraska and western Kansas; and south to western Texas, northern Sonora, and northern Chihuahua.
Irruptions of Clark’s Nutcracker may carry birds to the California coast (they have been recorded on off-shore islands) and as far east as western Ontario in Canada and Pennsylvania, Illinois, and Arkansas in the United States.
Both species use their long, sharply pointed bills to probe the ground when caching and collecting seeds. They also use them to determine the thickness of the seed coat, test whether a seed is empty or full, and, most important, hack open and shred unopened pine cones. Pinyon Jay and Clark’s Nutcracker, unlike other western jay species, do not have to wait for cones to open naturally to extract seeds. When you compare the size and shape of their bills with those of Western Scrub-Jay and Mexican Jay, two species that are much less reliant on seed caches, it’s easy to see why: Their bills are sturdier and sharper.
Other interesting and unique adaptations allow Pinyon Jay and Clark’s Nutcracker to hold and transport large numbers of seeds. The nutcracker drops pine seeds through an opening at the base of the tongue into a special pouch that is nothing short of amazing. An elastic sack-like extension of the floor of the mouth, it can swell enough to hold up to 95 seeds, which represents almost 13 percent of the bird’s total body weight. Pinyon Jay has evolved a similar adaptation: an expandable esophagus that allows it to hold and carry pinyon pine seeds. When full, its esophagus can hold up to 40 seeds, representing about 12 percent of its total weight.
It is one thing to collect and cache seeds, but quite another to be able to return later and find them, yet both the jay and nutcracker do this with astonishing accuracy. Clark’s Nutcracker has been observed flying directly to cache sites and digging through deep snow, even pecking through ice, to retrieve seeds that it had hidden eight to ten months earlier. Scientists estimate that it will relocate up to two-thirds of seeds that it cached up to 13 months earlier. How does it re-find seeds in altered landscapes many months after hiding them?
To find out, Balda and colleague Alan C. Kamil of the University of Nebraska Lincoln studied the two species extensively in northern Arizona, where they occur together around the San Francisco Peaks, and also conducted laboratory experiments on the birds’ ability to recover caches. The researchers hypothesized that the more a species depends on cached seeds for its survival in winter, when no other food is available, the better its spatial memory would be, and the results of their experiments proved them to be correct.
Both Pinyon Jay and Clark’s Nutcracker demonstrated exceptional ability to find hidden seeds, and they were significantly better at it than the closely related Western Scrub-Jay and Mexican Jay, which inhabit lower, warmer woodlands and are less dependent on caches for survival. Their laboratory experiments suggested that Pinyon Jay and Clark’s Nutcracker use both landmarks and internal compasses to navigate almost unerringly to cache sites.
Knowing this, you’ll understand why I can’t help but smile every time I see either species. The next time you come upon them, take the time to observe them carefully as they fly off with pilfered food, hack away at a pine cone, or cache seeds with scores of their kin. Their behavior speaks volumes about their biology, habitat preferences, breeding habits, even their evolution.
Charles J. Babbitt is a Phoenix lawyer and an avid birdwatcher. He is past president of the Maricopa Audubon Society and a past member of the Arizona Bird Committee. His article about the six warblers that breed primarily in Arizona appeared in our June 2012 issue. He wrote about finding Arizona’s 13 owl species in February 2011.