Irruptions?

[Dotch]

Any of you who are much more well informed than I have any inklings or thoughts on whether or not we might expect to see another winter with the kind of irruption we saw last season? Saw hundreds more redpolls and siskins last winter than in all my prior years combined. Just curious to know if I should put up a couple bulk bins for sunflower and thistle seed.

[Steve Foss]

Maybe borealhunter will chime in with his knowledge on this one.

If I recall my reading well, northern US irruptions are generally mostly about food shortages and sometimes prolonged harsh weather to our north. Many of our winter irruptive species go where the seed/berry crops particular to that species are good and avoid areas of poor production.

Here's a breakdown of the finch irruption forecast this winter from Tim G. Smart, a birder in our northern neighbor Ontario.

INDIVIDUAL FINCH FORECASTS

Individual finch forecasts below apply mainly to Ontario, but neighboring

provinces and states may find the forecast applies to them. An irruptive

raptor and three irruptive passerines are also discussed.

Pine Grosbeak: Expect very little or no southward movement into southern

Ontario because mountain-ash berry crops are excellent in most of the

boreal forest. A few should get south to Algonquin Park as in most

winters.

Purple Finch: Most Purple Finches should migrate south out of the

province this fall because many seed crops are poor in the north. This

finch has declined significantly in recent decades.

Red Crossbill: This crossbill comprises at least 10 "call types" in North

America. Each type has its cone preferences related to bill size and

shape. The types are exceedingly difficult to identify in the field.

Types 2 and 3 and probably 4 occur regularly in Ontario. Most Red

Crossbills prefer pines, but the smallest-billed Hemlock Type 3 (=

subspecies sitkensis of AOU Check-list 1957) prefers the small soft cones

of hemlock and white spruce when bumper in Ontario. However, it should be

absent from traditional areas such as Algonquin Park where hemlock and

white spruce occur together because these crops are poor there. White

pine Type 2 is the most frequently encountered Red Crossbill in the

province. Since white pine crops are low in most of the province, it

should be rare to absent this winter. Other Red Crossbill types are

possible in the province.

White-winged Crossbill: This crossbill has no subspecies or types in

North America. In Ontario, it prefers the small soft cones of white,

black and red spruces and hemlock. Many White-winged Crossbills left the

province this past summer after last winter's irruption. Some went into

northern Ontario attracted to the good spruce cone crops and were singing

and presumably nested. These birds may remain in the north this winter

and could breed again in mid winter if seed supplies last. White-winged

Crossbills will be rare or absent this winter in traditional areas such

as Algonquin Park because spruce and hemlock cone crops are low.

White-winged Crossbills should appear this winter in Newfoundland and the

Maritime Provinces and the northern New England States, where spruce cone

crops are good to heavy.

Common and Hoary Redpolls: Redpolls are a birch seed specialist in

winter. Since the birch crop is poor in northeastern Ontario and Quebec,

a few Common Redpolls should move south into southern Ontario and farther

east and south. However, most redpolls may be drawn to good birch crops

in northwestern Ontario and westward in the boreal forest into

Saskatchewan.

Pine Siskin: Siskins are a conifer seed specialist when they winter in

northern Ontario. Hemlock seed is another favorite in central Ontario.

Most siskins departed the province early this past summer and appear to

have gone mainly to western Canada. Banding recoveries show that siskins

wander both ways between eastern and western North America. Siskins are

currently very scarce in the Northeast. If siskins find good conifer

crops in the Northwest, such as the interior of British Columbia, they

will stay to winter and breed. It is uncertain whether many will return

east this fall to winter in northwestern Ontario, the Maritime Provinces

and northern New England States, where cone crops are good to excellent.

Evening Grosbeak: Breeding populations are much lower now than 35 years

ago due mainly to a decrease of large outbreaks of spruce budworm

beginning in the 1980s. A very few grosbeaks may move south from

northeastern Ontario and Quebec where coniferous and deciduous seed

supplies are generally poor. If any come, there are large crops of

Manitoba maple seeds and plenty of sunflower seeds at feeders waiting for

them.

FOUR MORE IRRUPTIVE SPECIES

Northern Goshawk: A good flight is very possible this fall or next.

Goshawks in the boreal forest in winter prey on hares, grouse and red

squirrels. Snowshoe Hares have been abundant in parts of northern Ontario

the past few years and they should crash soon. Also, Ruffed Grouse likely

had a poor breeding season due to a cool, wet spring and summer, which

lowered chick survival.

Blue Jay: The flight began in the second week of September. This year's

flight is much larger than in 2008 along the north shorelines of Lakes

Ontario and Erie because most acorn, beechnut and hazelnut crops were

poor this summer in Ontario with some local exceptions. Many fewer jays

will winter in Ontario because most could not find enough food to store.

Red-breasted Nuthatch: Movements of this nuthatch in Ontario are linked

to cone crop abundance, particularly white spruce, white pine and balsam

fir when bumper. There has not been a noticeable southward movement along

Lakes Ontario and Erie, indicating this is not an irruption year for it

and associated winter finches such as White-winged Crossbills and Pine

Siskins. However, Red-breasted Nuthatches will be scarce this winter in

central Ontario such as Algonquin Park and in northeastern Ontario and

Quebec because cone crops there are generally poor in these areas. Many

nuthatches likely dispersed to better cone crops north and west of Lake

Superior and east to the Maritime Provinces.

Bohemian Waxwing: Like the Pine Grosbeak, this waxwing is a mountain-ash

berry specialist in winter. Mountain-ash crops are high around Lake

Superior and in many areas of northern Ontario. Crops are also good in

Quebec, Newfoundland and northern New England States so this nomad may

show up in these areas this winter. Its breeding and winter ranges in

eastern North America have expanded in recent times. Range maps in field

guides show Bohemians breeding east to James Bay, but recently they have

been found in summer scattered across northern Quebec and Labrador.

Historically they were very rare in winter on the island of Newfoundland,

but are now abundant there some winters. Their winter range movements

have also expanded to other eastern areas because of planted European

mountain-ashes and ornamental crabapples.

[Borealhunter]

As far as owls Steve is correct and there is no way to predict a Great Gray Owl irruption but you can predict a Boreal Owl irruption which occurs every 5 years and we just had an irruption last winter which wasn't spectacular as far as finding them.

Steve is the Tim Smart Finch forecast for 2009-10? There is a finch forecast which comes out by another birder/researcher in Michigan/Ontario but like Steve says its all about food crop availability and prey numbers.

Mike

[Steve Foss]

Mike, it is the 2009/2010 forecast. It was issued about two weeks ago.

[Dotch]

Thanks to you both for your insight. Looks like we'll have to play it by ear on the bulk bins.