This magpie is confined to California. Its black-and-white plumage has blue-green iridescence, and its bill is yellow. It lives in open oak woodland and grassy oak savanna, often near plains, orchards or fields.
Black and white are the main colours, with feathers that shimmer blue-green and yellow on the body. The yellow bill gives the species its common name.
It walks on the ground to take insects and other invertebrates, as well as acorns and grain. Pairs build a large domed nest high in a tree, and both parents take part in nest building and chick care.
An extinction-risk assessment has not been added yet.