Type 7 Crossbill

Type 7 Crossbill

Geographic Range. Like Type 5, this form of crossbill has only been recorded in western North America. It is not known whether it actually does not occur in the East; it just has not been recorded there. It is likely that this form is nowhere common, but if it has a center of abundance, it would be in British Columbia or Alberta.

Ecology and Habitat. This form has been found in both lodgepole pine (Pinus contorta) and Englemann spruce (Picea englemanni) forests. It may breed sympatrically with Type 5 over much of its range.

Natural History Notes. Almost nothing is known regarding the comparative natural history of this form. It is a medium-sized crossbill, averaging smaller than Type 2 and Type 5, but is not as small as Type 1 or Type 4.

Vocalizations. The flight calls of Type 7 crossbills are similar to those of Type 3 in that they have an down-up-down pattern. However, the "up" portion in the center of the call note of Type 7 is stronger than that of Type 3. To the human ear, Type 7 flight calls sound like a "warbly" version of Type 2 flight calls. The excitement call, or toop, of this form has not been recorded. The alarm calls are highly distinctive in that they contain extensive harmonics, like those of Type 5, but average longer in duration than those of that form.