Geographic Range. To date, this form of crossbill has only been recorded in the Chiricahua Mountains of southeast Arizona. However, based on museum specimen records, this form may be the most common crossbill throughout the highlands of Mexico. These large crossbills range as far south as southern Mexico. It is not known how frequently this form "invades" northward across the United States border nor how far north it may range.
Ecology and Habitat. Given the large bill size of this form, it is predictable that it is associated with large, hard-coned pines. In the Chiricahuas, it was seen to be associated with high-elevation ponderosa and Apache pines (Pinus ponderosa and P. englemanni). There is little doubt that it would not hesitate to obtain a "snack" from Douglas fir or other soft-coned conifers.
Natural History Notes. This is the largest-billed crossbill in North America. Males are often a dark, rich blood-red color, in contrast to Type 2 crossbills which average paler and oranger. Little is known regarding the natural history of this form. Based on specimen records of juveniles, it appears that it's primary breeding season is January to February.
Vocalizations. Based on geographic considerations, the crossbill most likely to occur with this form (in southern Arizona, for example) is Type 2. The alarm and excitement calls of Type 6 crossbills are quite distinctive from those of Type 2, but the flight calls are less easy to distinguish.