White-winged Crossbill Irruption Year

As we all wait for warmer weather and the frog songs and wildflowers it brings, there’s something fascinating happening in the woods right now. We are experiencing what is known as an “irruption year” for some finch species, including the very unique White-winged Crossbill.

In the birding world an “irruption” usually implies the movement of northern-wintering species to more southern locations in years of low food availability in the northern boreal forests. The shortages are based on the cyclical availability of food sources like pine cones. The irruption we are experiencing occurs about once every 10 years so it’s pretty neat to see birds that only visit once in a decade.

It’s especially exciting to be visited by the very unique White-winged Crossbill which, of the over 10,000 bird species on earth, is one of only five species (all finches) that has a crossed bill. Their unique beak is an adaptation for harvesting pine cone seeds that other birds can’t access. They are incredibly efficient eaters and can consume up to 3,000 seeds a day!

White-winged Crossbills fly in flocks all year, even during nesting season, so keep an eye open for groups of these unique birds on your next adventure in hemlock or spruce trees as they head back north.

Click HERE to watch an interesting video of these birds at work from the Cornell Lab of Ornithology.

(photo by Stan Lilley)