The male has a red body with dark wings and the female has an olive/yellowish body with dark wings. The unique bill of the red crossbill is what sets it apart from other finches. The crossbill has a thick curved bill with crossed tips. This striking feature is what gives this bird its name and makes the crossbill easy to identify.
The red crossbill may be easy to identify, but is not easily found in New Mexico. Red crossbills travel in flocks year round and wander erratically in search of food. They are totally dependent upon conifer seeds and can be found only in conifer forests consisting mainly of spruce, Douglas fir and hemlock. Their cross tipped bill is specifically designed to pry open tightly closed cones. Crossbills place the tips of their slightly open bill under a cone scale, biting down with their very strong biting muscles which pushes the scale up, exposing the seed. Red crossbills will eat sunflower seeds at backyard birdfeeders, but are uncommon visitors.
Most birds breed and raise young only in the spring and summer when natural insect populations are available to feed to their young. Red crossbills feed mainly conifer seeds to their young, so if there is an abundance of conifer seeds, the crossbill can breed year round. Juvenile red crossbills maintain their brown streaked plumage from January through September. This juvenile plumage does differentiate them from adult crossbills but they can still be identified by their unique cross tipped bill.
There is evidence of as many as eight different species of red crossbills. Red crossbills have a particular call given in flight. Eight different flight calls have been documented along with a slight variation of bill size and shape with each differing flight call. It has also been observed that red crossbills with differently shaped bills prefer to feed on different tree species that have differently sized cones.
The red crossbill has a stable population of approximately 20 million. There is however some decline in population in the Northwest. Because rapid deforestation is the likely cause of these declines, maintaining healthy conifer forests is essential for the survival of this unique bird. Be sure to watch for flocks of red crossbills clinging to pinecones when hiking in the many forests of New Mexico.
Mary Schmauss is the owner of Wild Birds Unlimited in Albuquerque. A lifelong birder and author of For the Birds: A Month-by-Month Guide to Attracting Birds to your Backyard.