[NatureNS] FWD: Winter Finch Forecast

Date: Sat, 09 Sep 2006 06:27:22 -0300
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GENERAL FINCH FORECAST 2006 - 2007

This is one of those rare years when most conifers (softwoods) and
broad-leaved deciduous trees (hardwoods) have synchronized bumper
seed crops across much of Eastern Canada and the bordering United
States. It will be an excellent winter to see winter finches in
northern Ontario and central Ontario (e.g., Algonquin Park). Very few
boreal finches will move south of Ontario this fall and winter. Most
finches likely will be scarce even in southern Ontario south of the
Canadian Shield this winter, despite bumper seed crops on native and
ornamental species. There also are bumper cone crops in Quebec, the
Maritime Provinces, New York and northern New England States, so
finches will be there too, but in what numbers is the question,
because excellent crops are so widespread this year. There are good
cone crops west of Lake Superior in northwestern Ontario, but cone
quality diminishs towards Manitoba because of severe drought
conditions this year. Cone crops are generally poor at the
continental extremes in Newfoundland and Alaska. Both White-winged
and Red Crossbills have been arriving in Ontario since late June in
areas with bumper cone crops. In addition to individual finch
forecasts, I also comment on other irruptive species, such as the
Red-breasted Nuthatch, whose movements are linked to winter finches.
I added a new section this year called Finch Notes. It discusses
bumper seed crops, how crossbills find cone crops, when crossbills
move to bumper crops, when crossbills nest, road-killed finches, and
where to see finches this winter in Ontario.

INDIVIDUAL FINCH FORECASTS

Pine Grosbeak: Most Pine Grosbeaks will stay in northern Ontario
because the berry crop on mountain-ash (rowan berries) is excellent
to bumper this year. As well, the large seed and berry crops on other
trees and shrubs provide ample buffer food supplies to keep the
grosbeaks in the north. A few Pine Grosbeaks may drift as far south
as Algonquin Park where they are seen most winters.

Purple Finch: The excellent tree seed crops on most coniferous and
deciduous trees suggest that most (not all) Purple Finches will spend
this winter in northern and central Ontario. Some may drift south in
late winter and show up at feeders, which is typical of this species
in big seed years as seed supplies diminish in late winter.

Red Crossbill: Taxonomy and nomenclature are hopelessly confused. The
Red Crossbill complex comprises at least eight types or forms
(possibly full species) with different vocalizations and bill sizes
related to cone preferences. Two or three forms are regular in
Ontario. One prefers hemlock cones and the others are adapted mostly
to pines, mainly white pine in Ontario. Red Crossbills have been seen
and heard singing in hemlocks in August suggesting that the
small-billed hemlock subspecies 'sitkensis' has moved into central
Ontario where hemlock cone crops are excellent as in Algonquin Park
and the Haliburton Highlands. The hemlock form has the smallest bill
of all Red Crossbills, even smaller than the White-winged Crossbill's
stubby bill. Road-killed 'sitkensis' can be identified by measuring
their bills (culmen 13.5-15 mm). White pine cone crops, unlike other
conifers, are poor in most of central Ontario such as Algonquin Park.
However, some areas of northeastern Ontario have good white pine
crops such as Marten River and Timmins. Watch for pine types of Red
Crossbills wherever white and red pines have good cone crops. Since
spruce cones are so abundant this year, I expect that Red Crossbills
will be found feeding in spruce to some extent this winter.

White-winged Crossbill: Like a pendulum, White-winged Crossbills move
back and forth across the northern coniferous forests from
Newfoundland to Alaska searching for cone crops. White-winged
Crossbills will be widespread and perhaps common in many areas of
northern and central Ontario because of the bumper seed crops on
spruces, tamarack, balsam fir and hemlock. I expect that the highest
concentrations of White-wings will be in northeastern Ontario between
Lake Superior and Quebec where the super bumper crop of white spruce
cones is "a 1-in-20-year cyclical phenomenon" making this is a rather
rare event in seed production for white spruce (Scott McPherson,
pers. comm.). White-winged Crossbills began increasing in northern
Ontario in late June and increased during July associated with big
cone crops. They are singing and feasting on an abundance of cone
seeds and probably nesting. They likely will begin nesting again in
early 2007. White-winged Crossbills in Algonquin Park have been
widespread in small numbers since July and are singing. Nesting is
suggested by two sightings of recently fledged young in August.
White-winged Crossbills possibly came from western Canada and Alaska
wandering eastward searching for cone crops. One reason why there are
no subspecies on this continent versus the eight or more types of Red
Crossbills is that White-winged Crossbill populations oscillate east
and west across North America, and thus are constantly mixing. This
allows outcrossing and gene flow among populations, suppressing the
formation of geographical variation.

Common Redpoll: This is not a flight year for redpolls in southern
Ontario. Most Common and Hoary Redpolls will be in northern Ontario
this winter because seed crops on white birch and alder are excellent
to bumper there. As well, yellow birch has an excellent crop from
southeastern Lake Superior into Quebec. This large crop will stall
any redpolls wandering south of the boreal zone. A few redpolls may
get as far south as Algonquin Park, but likely no farther.

Pine Siskin: Most Pine Siskins will winter in northern and probably
central Ontario this winter because cones crops are bumper on
spruces, balsam fir, tamarack (larch), cedar and hemlock. Flocks of
siskins can be identified at a distance by their distinctive flight
formation. They swirl in tight flocks whereas redpolls fly in loose
undulating flocks. Siskins should breed early next spring in northern
Ontario. Only one subspecies occurs across Canada, indicating that
highly nomadic siskin populations mix from coast to coast, inhibiting
the formation of geographical variation.

Evening Grosbeak: Evening Grosbeaks will stay in the boreal forest
this winter because tree seed crops are excellent on conifers and
hardwoods such as black ash. Expect a few in Algonquin Park,
particularly around the feeders at the Visitor Centre. The eastern
population of Evening Grosbeaks started declining in 1980 as large
outbreaks of spruce budworm subsided. The population is probably
stable now, but much reduced from the 1970s when Evening Grosbeaks
were common at bird feeders.

OTHER IRRUPTIVE SPECIES

Blue Jay: A small to moderate flight is expected. The good to
excellent crop of beechnuts on American beech in most areas of
central and southern Ontario should keep most Blue Jays from
migrating south this September and October along the shorelines of
Lakes Ontario and Erie. B