Yellow-billed Magpie

by Mike Stiles

If a birder wants to check off every bird in North America, eventually he or she must come to central California for the Yellow-billed Magpie. This month we will discuss this beautiful and fascinating bird, found nowhere else in the world.  

The Yellow-billed Magpie is endemic (the ecological state of being unique to a particular location) to a small portion of California, ranging from Sacramento south through the San Joaquin Valley, and in the coastal valleys from San Francisco to Santa Barbara. Endemism is very unusual in birds, especially to such a small area, and our magpie is one of only two truly endemic birds in California. The other is the Island Scrub Jay found only on Santa Cruz Island. It is interesting that our only endemic birds are in the same family, the corvids, which include the magpies, jays, crows, and ravens. In our county they can be found in the drier inland valleys, usually associated with oak groves, but are also found in suburban settings. Our county does have a few isolated pockets of the magpies away from the interior, along Turri Road east of Los Osos, and on the Cal Poly campus.  

They are closely related to the Black-billed Magpie that ranges over much of the western United States from Alaska to northern Arizona and east through the plain states, but are absent from the immediate coast. The two birds differ in only the color of the bill and the bare area around the eye, and are thought to have split when the Sierra Nevada Mountains were formed, separating the two into isolated populations.  

Our magpies are a large bird, just slightly smaller than a crow, with a black head and chest, white belly, and a very long tail. The tail and wings are an iridescent blue-green, and of course the feature that gives them their name, the bright yellow bill and bare skin around the eye. Their white primary feathers are conspicuous in flight. Their loud, raucous calls –wock, wock, wock, weer, weer, weer—can be heard for great distances.  

They are a very social bird, and when not in the breeding season can congregate into flocks of many hundreds of individuals. To establish a territory they often watch from the tops of trees and will fly down to the ground and "Parallel Walk" or walk side by side at the edge of each bird's territory, each male holding his tail nearly vertical as they strut together. That I would like to see. They can be aggressive toward their predators and will gang up on hawks and owls and other perceived threats.  

Yellow-billed Magpies build a very unusual nest, usually high in the tree, and out near the end of the branch. Both male and female build a large globe-shaped nest which can be nearly three feet in diameter. The base of the nest is comprised of sticks and mud (or dung) with a mud bowl lined in some soft material for the eggs. The upper part of the dome can have two entrances but are often hard to find—at least for biologists I assume. Someone once dismantled a magpie nest and counted 1,573 sticks and weighed it at nearly 25 pounds.  

Because of their limited range, and our human habit of encroaching on our wild spaces, Yellow-billed Magpie numbers are dwindling and they have been placed on the Audubon Society's Watch List. Habitat destruction and fragmentation through housing and agriculture practices have hurt some populations. Magpies, like all corvids, are very susceptible to West Nile Virus. Christmas Bird Counts and breeding bird surveys have shown a substantial decrease in the number of magpies, and nearly 800 dead magpies in 2004-2006 tested positive for the virus.  

So, what can I do, you ask. The first part of any conservation effort is to establish just how many Yellow-billed Magpies there are. You can take part in Audubon California's Yellow-billed Magpie survey taking place June 4-7. Go to the Audubon survey webpage for more information and to submit your sightings. Just pick a spot, count the magpies you see, and submit the information. You can never go wrong watching those beautiful birds.  

Thanks to Brad Schram for information on his favorite bird and for the photographs. Much information has been gleaned from the Birds of North American Online.

Burrowing Owl on banner by Cleve Nash.