Tuesday, March 5, 2013

Winter Finch Extravaganza!

Across southern Canada and much of the United States, a variety of winter finch species have irrupted south of their typical winter range to the delight of many birders. While this pattern is most pronounced in the east, with huge numbers of both Red (Loxia curvirostra) and White-winged Crossbills (Loxia leucoptera), as well as Common (Acanthis flammea) and Hoary Redpolls (Acanthis hornemanni), we here in Laramie are also seeing good numbers of Red Crossbills and Common Redpolls, which are usually very rare in southern Wyoming. In addition to the winter finches, irruptions such as these also see large flights of Red-breasted Nuthatches (Sitta canadensis) and Bohemian Waxwings (Bombycilla garrulus), both of which are showing up in parts of Wyoming.

White-winged Crossbill (Loxia leucoptera) - Long Island, NY
Red Crossbill (Loxia curvirostra) - Laramie, WY
While finch irruptions are fairly typical on a cyclical basis, the one that birders are seeing this winter is unusually large, due to widespread seed crop failure, including those of various coniferous trees, birches (Betula), alders (Alnus), and Mountain Ash (Sorbus sp) (Erskine and McManus 2003, Howe et al. 2012). As finches in the north wander in search of good seed crops, they move southwards in huge numbers (Pittaway 1998).

In addition to the irruptive species that only visit Wyoming on occasion, winters in Wyoming also host a number of other great finch species, including Pine Grosbeaks (Pinicola enucleator), Evening Grosbeaks (Coccothraustes vespertinus), and all three rosy-finch species (Leucosticte sp). Recently around Laramie, we have seen good numbers of Gray-crowned Rosy-finches (Leucosticte tephrocotis) and Red Crossbills, as well as smaller numbers of Pine Grosbeaks and Common Redpolls. 

Gray-crowned Rosy-Finch (Leucosticte tephrocotis) - Buford, WY
Pine Grosbeak (Pinicola enucleator) - Albany, WY
Common Redpoll (Acanthis flammea) - Albany, WY
As winter turns slowly into spring here in Wyoming, we can expect to continue to see many of these irruptive species well into April before heading back northward.

For more information on patterns of winter finch irruptions, see this very informative and interesting write up on eBird by Ron Pittaway.

Note: all photos in this post are © Shawn Billerman


Erskine, AJ and R McManus. 2003. Supposed periodicity of redpoll, Carduelis sp., winter visitations in Atlantic Canada. Canadian Field-Naturalist. 117(4), 611-620 

Howe, EJ, ME Obbard, and J Bowman. 2012. Prior reproduction and weather affect berry crops in central Ontario, Canada. Population Ecology. 54, 347-356

Pittaway, R. 1998. Winter Finches. Ontario Field Ornithologists News

No comments:

Post a Comment