Bird of the Month: Marsh Wren
By Andy McCormick
Scientific Name: Cistothorus palustris
Length 5 in
Wingspan 6 in
Weight 0.39 oz
AOU Band code MAWR
Clark’s Nutcracker was named for Captain William Clark by Alexander Wilson who analyzed the skin brought to him following the Lewis and Clark Expedition. Clark initially thought the bird was a species of woodpecker but later it was classified as a jay. Sibley notes, “In some respects, [nutcrackers] are intermediate between jays and crows, because of their short tails, straight bills, and direct flight, and they walk rather than hop (jays always hop).” The genus name means nutbreaker, from Latin nucis, a nut, and frango, to break, shatter, smash. Columbiana, references the Columbia River area where the bird was found by Clark (Holloway).
Clark’s Nutcrackers inhabit mountain coniferous forests where they use their bills to extract seeds from cones of ponderosa, whitebark and pinyon pines. They store seeds by dropping them into a sublingual pouch with a slight backward toss of the head and upward thrust of the bill and then cache them in the ground, in cracks in trees and under bark (Tomback). The pouch can hold anywhere from 30-150 seeds depending on the type. Total number of seeds cached by a single bird in a summer-fall season can reach 30,000. The seed caches allow them to breed in the late winter even when snow covers the forest (Kaufman).
Clark’s Nutcrackers have short tails for a Corvid but have long wings. Their gray bodies contrast with the black and white wings and tail. The long, straight bill is black as is the eye. Although similar, the Gray Jay has dark feathers on the head and does not have the black and white wings and tail.
The nutcrackers are non-migratory but will move to lower elevations during poor cone-producing years. They have a great ability to relocate their caches which can be miles apart. These birds are most often found far from human habitation, but have learned that visiting campgrounds and picnic areas can be bountiful and will join humans for meals.
Their nest is constructed by both sexes at high elevation in coniferous trees. It is built on a platform constructed of twigs. The cup is deep and lined with bark strips and pine needles. Usually 2-4 pale green, lightly spotted eggs are deposited and incubated by both parents for 16-18 days. The young are fed from the previously stored seeds and take first flight in about three weeks.
Clark’s Nutcrackers are part of an important ecosystem that includes the whitebark pine, the mountain pine beetle and grizzly bears. Clark’s Nutcrackers by caching pine seeds in the ground have contributed to seed dispersal for the whitebark pine and forest regeneration (Tomback). The seeds caches are raided by bears and other mammals which use them as an important food source. In recent years mountain pine beetle infestation has weakened trees and contributed to fires in whitebark pine forests in the northern Rocky Mountains and is now threatening the Cascade Range (Murray & Siderius). Flexibility in their choice of pine seeds has allowed Clark’s Nutcrackers to maintain a stable population.