Cassia Crossbill
Cassia Crossbill
Loxia sinesciuris
At a Glance
Formerly considered a localized form of Red Crossbill, the Cassia Crossbill was officially recognized as a full species in 2017. It lives only in lodgepole pine forests of the South Hills and Albion Mountains in Cassia County, southern Idaho. These two mountain ranges are unusual in having no red squirrels, which feed heavily on pine cones elsewhere. As a result, the lodgepole pines in these mountains have abundant cones, and the Cassia Crossbills are specially adapted to feed on the seeds from those cones. (The species name of this crossbill, sinesciurus, means "without squirrels.")
All bird guide text and rangemaps adapted from Lives of North American Birds by Kenn Kaufman© 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Perching Birds
IUCN Status
Least Concern
Habitat
Forests and Woodlands
Population
5.800
Range & Identification
Migration & Range Maps
Most crossbills are nomadic and wander long distances, but the Cassia Crossbill stays in the same limited range year-round, making only minor local movements.
Description
6 1/4" (16 cm). A very localized specialty of southern Idaho. Almost identical to Red Crossbill, but averages heavier-billed than the Red Crossbills that wander through its limited range. Best identified by callnotes.
Size
About the size of a Robin, About the size of a Sparrow
Color
Black, Brown, Green, Olive, Red, Yellow
Wing Shape
Pointed, Rounded, Short
Tail Shape
Notched
Songs and Calls
Compared to the voices of other Red Crossbill types that occur in southern Idaho, flight calls of Cassia Crossbill are very low-pitched and hard, like chup-chup instead of kyip-kyip.
Call Type
Chatter, Chirp/Chip, Twitter
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Behavior
Feeding Behavior
Like other crossbills, usually forages in flocks. Clambers about over the cones of lodgepole pines, using its odd crossed bill tip to pry the cone scales apart to get at the seeds inside.
Diet
Feeds mainly on the seeds of lodgepole pine.
Nesting
Unlike other crossbills, which may nest at almost any season, Cassia Crossbills are consistent in their timing. They usually begin building their open cup-shaped nests in late March or early April, and the breeding season ends by late July.
Conservation
Conservation Status
Common in its limited range, with an estimated population of about 6,000, but vulnerable just because its total distribution is so small. The species could be wiped out by fires or other factors in the two mountain ranges where it lives.