|11/19/2014 3:22:00 PM|
The Winter Finch Forecast-
by Don ReimerAs December approaches, birders and feeder watchers anticipate the arrival of "winter finches," that diverse group of nomadic feathered wanderers that vacates the northern boreal forest and heads southward in certain winters. Successfully forecasting the movements of anything wearing feathers is a sketchy blend of avian science, birder's intuition and some portion of blind luck.
Seasonal availability of food resources is the main driving force behind these mass, irruptive movements that occur in a rather cyclical fashion. Influenced to some extent by yearly climatic fluctuations and multi-year precipitation patterns, annual production of cone and fruit crops varies by individual tree species. The key tree types affecting finch movements in the boreal zone are spruces, birches and mountain ashes.
Although Canadian biologist Ron Pittway's forecasts apply mainly to Ontario Province, adjacent provinces and the northen tier of states often share similar results. And even within the regional predictions, there can be localized exceptions for individual species.
So what's the forecast this year? Small to medium-sized flocks of streaked Pine Siskins are already whizzing through our coastal areas. These scrappy little fellows will definitely reduce your nyjer seed stores if they swarm your home's thistle feeders.
Be on the lookout for Purple Finches this winter. This active, handsome finch prefers black oil sunflower seeds. Males have a uniform raspberry red head and nape, with a rosy frosting across the breast. Purple Finches are told from similar looking House Finches by their distinctly notched, slightly forked tail (squared off in House Finch).
With some early reports for Maine, we can hope for a flight of Evening Grosbeaks this year as small numbers may venture southward. These spectacular and vocal yellow, black and olive finches enliven feeding stations that offer black oil seed. Linked to expansive outbreaks of spruce budworm across upper Maine and Canada, breeding populations peaked during the1940s to 1980s.
Scattered numbers of Pine Grosbeaks nest in extreme northern Maine, but the main population exists farther north. An extremely tame and approachable species, females and immature specimens of a burnt-orange hue outnumber the red-and-gray adult males.
How tame are these birds, you ask? Several winters back, I hand-fed a sprig of crabapple to a single bird perched in a tree within arm's length - such a unique experience as the vagrant grosbeak reached down to gently nibble a sliver of frozen fruit from my outstretched fingertips.
With plentiful mountain-ash crops in much of boreal Canada, odds are against a heavy presence of Bohemian Waxwings this time around. Bohemians are attracted to berries on European mountain ash, ornamental crabapples and buckthorn berries. One positive development is the species' recent eastward expansion of its breeding range across northern Quebec that is tied to an abundance of buckthorn berries in settled areas there.
Since birch seed crops are ample here in Maine, we can anticipate Common Redpolls in moderate to strong southern flights. With its distinctive red forehead patch, this tiny finch of tundra scrub also consumes alder catkins and, of course, that tasty nyjer seed you provide them. While much rarer, a few Hoary Redpolls (generally whiter bodied with a stubbier bill) could appear among the Common Redpoll flocks.
Red and White-winged Crossbill numbers may be reduced this year due to poor cone crops in our region. Crossbills use their scissor-crossed mandibles to pry open coniferous cone scales and extract the nutritious seeds with their tongue.
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