The red crossbill (Loxia curvirostra) is so dependent on the seeds of pine cones for its survival that this member of the finch family breeds in the coniferous forests of boreal (northern) Canada and in the mountainous West. (Red Crossbills also are found in Eursia.) Although red crossbills are generally nonmigratory, they are an irruptive species meaning that they will shift their usual wintering grounds to areas where food is more plentiful. For this reason, red crossbills can occasionally be found throughout most of North America. This bright bird with the odd bill resides in our area, but Leonard and I never know when or where we might see a flock. It depends on the pine seed distribution and abundance each year.
Male crossbills have a deep brick red to reddish yellow body while females are grey to olive in color with a greenish yellow chest and rump. The wings and tail of both sexes are blackish brown. The wings do not have bars. The tail is short and notched. The legs and feet are grey-black. However, the most interesting feature of the red crossbill is its thick bill with crossed tips. There is much variation in the size and shape of crossbills’ bills. The bill can cross in either direction.
Juvenile red crossbills are mostly brown with lighter undersides and heavy dark streaking.
How can the red crossbill eat with such an awkward looking bill? Actually the bill shape helps the crossbill get at the seeds in closed cones. When the crossbill puts its slightly opened bill under a pine cone scale and bites down the crossed tips push up the scale and expose the seed – a very specialized adaptation.
Red crossbills rely so heavily on conifer seeds that they will breed whenever they find a good supply, even in the winter.
Red crossbills feed in flocks amid the conifers and can also often be seen getting grit and salt from along roadsides, which is exactly what the pictured birds were doing near the agricultural inspection station along Highway 139 in California (Modoc County).