Yellow-billed magpie

The black-billed magpie (Pica pica) occurs across Europe, Asia, North Africa and western North America, an exceedingly common bird.

The yellow-billed magpie (Pica nuttalli), identical in appearance to its black-billed relative except for bill color, occurs only in an area about 500 miles north to south and about 150 miles across, in the central part of California. Within that limited range they are quite common, nesting in colonies in groves of tall trees. They are most numerous in open country and where riverside groves of oaks, cottonwoods and sycamores border upon farmland. They are omnivorous, eating whatever they can get, from acorns to carrion to grasshoppers...whatever is available. Their nests are a bit smaller than those of the black-billed magpie (a domed structure more often two feet in diameter than the three feet of the latter species), and they tend to lay fewer eggs. Black-billed magpies fledge (leave the nest) in 25 - 29 days. The fledging time for yellow-billed magpies is not known.

All magpies are noisy and rather aggressive, from the family Corvidae, which also includes the crows, the jays and the ravens. Like their relatives, intelligent, adaptable birds.

But....what's with the yellow bill? And the other slight but perhaps important differences? How did this come about? Why only in Central California? Was one bird, long ago, a mutant and spread this mutation across this area only? The two, black-billed and yellow-billed, do not occur together. In California, the black-billed magpie is found only in the Sierra Nevada Mountains and to the east (all the way across the center of the continent); the yellow-billed only in the Central Valley.

One of nature's little puzzles. Perhaps DNA studies could answer some of these questions, but in a world of limited funding, where we have far more important (to us) matters to investigate than yellow-billed magpies, the answer may never be known. The magpies, so far as we can tell, don't care.

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For the factual information see Kaufman, Kenn, Lives of North American Birds, Houghton Mifflin Company, Boston, New York, 1996