Saturday, November 13, 2010

White-winged Crossbill

Yesterday, friend Diana stopped by and we had a spot of tea. A bird suddenly flew into our living room window. Judy saved the critter as she usually does very effectively. Diana and I went out to see the bird and found it to be a white-winged crossbill. This is a new one species for us. The photo above is a female. Males are more rose colored.

A close look at this crossbill reveals a curious adaptation. The long tips of the upper and lower bill don’t meet, but instead cross over each other. The bills of young birds are not crossed at hatching, but cross as they grow. The Crossbill bites between the scales of a cone and pries them apart by opening its bill, then dislodges the seed with its tongue.

White-winged crossbills can be found in large flocks year round and call when they are foraging in an unproductive area. When many seeds are available they remain quiet. If only a few birds call, the flock continues to forage, but if a number of birds call, the flock will move on to find a more productive spot. Their bills are adapted for removing seeds from cones, and they start at the bottom of a cone and spiral upward, prying open each scale and removing the seeds with their tongues. The bills can cross in either direction, and the direction of the cross dictates the direction that the bird spirals up the cone. They can eat up to 3,000 seeds a day.

A Red Crossbill below illustrates this unusual beak.

By the way, Judy once again came through and her gentle touch "healed" the bird and off it flew!


Post a Comment

<< Home