"Gambel's" White-crowned Sparrows

A western form White-crowned Sparrow (Zonotrichia leucophrys) was banded by the Rouge River Bird Observatory on 20 October 2006, described below and compared with typical eastern and “intergrade” forms. There is a very nice article on identifying subspecies, with range maps, in a 1995 issue of Birding (27:182-200). Two other web pages, Oiseaux Birds and David Sibley’s blog also have a nice set of comparative photos of some of the variations.

Adult White-crowned Sparrows of all subspecies have black and white head stripes, while juvenile birds have brown and tan head stripes. Here are some examples of juvenile White-crowned Sparrows banded at RRBO, concluding with the western “Gambels” type banded in 2006.

Above is a  typical eastern hatching-year White-crowned Sparrow (Z. l. leucophrys).  Characteristics include a deep-based, pinkish bill with a dark tip, a medium-brown crown stripe, and a dark line through the eye that connects to the crown stripe in front of the eye.

This White-crowned Sparrow, banded on 16 Oct 2006, shows traits of an intergrade between the eastern form and the western “Gambel’s” White-crowned Sparrow form. Bill shape and color and crown color are similar to the eastern form.  The lack of dark feathering between the eye and crown is more like the western forms.

This White-crowned Sparrow banded on 20 Oct 2006 is most like the western “Gambel’s” form (Z. l. gambelii).  It not only lacks dark feathering between the eye and crown, but has a thinner, orange bill which is yellowish at the tip (described as looking like “candy corn”), and a more rufous crown stripe coloring.

This adult White-crowned Sparrow banded on 22 Oct 2012 is also a good candidate for the western “Gambel’s” form. It obviously lacks dark feathering between the eye and crown, the bill shape is farily narrow, but the bill color is a little ambiguous