Saturday, September 24, 2011

Winter Finch Forecast

Purple Finch / USFWS Photo
Even though the season just turned to autumn, Ron Pittaway has issued his annual forecast for the migration of winter finches and associated birds in eastern Canada and the northeastern United States. This is a useful service for birders since many finch species do not follow the same migration pattern each year. Instead they move in response to the availability of seed crops, which vary from year to year. If the seed crop in the boreal forest is really good, finches stay in the boreal forest. If the crop is sparse, they move to a location with a better crop, which could take them south, west, or east. Heavy southward movement of one or more finch species is known as an "irruption."

This year the seed crops are good, so mass southward migration is unlikely. These species seem the most likely to wander south:
PURPLE FINCH: Purple Finches will be uncommon in Ontario, but probably in higher numbers in Atlantic Canada, New York and New England where cone crops are excellent. A few may frequent feeders in southern Ontario. The Purple Finch has declined significantly in recent decades. Some suggest it declined due to competition with the House Finch. However, the drop in numbers began before House Finches were common in eastern North America and also occurred where House Finches were absent. A better explanation for the decrease is the absence of large spruce budworm outbreaks that probably sustained higher Purple Finch populations in the past....

PINE SISKIN: The nomadic siskin is a spruce seed specialist. There are currently large numbers of siskins in Yukon including a high proportion of hatch year birds. They will move because the spruce crop is average in Yukon and Alaska this year, possibly coming to the East. Siskins are expected to be widespread across Ontario this winter. Good numbers are likely to be drawn to the excellent spruce and hemlock crops in Atlantic Canada, New York and New England....

RED-BREASTED NUTHATCH: This nuthatch is a conifer seed specialist when it winters in the north and its movements are triggered by the same crops as some of the boreal finches. There has been very little southward movement indicating that this nuthatch will winter in areas with heavy cone crops such as the boreal forest, Quebec, Atlantic Canada, New York and New England States.
Read the full report for information on the other species. To read more about which birds are classed as winter finches and their habits, see this essay by Ron Pittaway (pdf).