Winter visitors toIllinois sometimesinclude somespecies typicalof more northerlyclimates.
Snow Birdsof theFeatheredVarietyStory By Kathy Andrews
Winter. There are those whoanxiously await its arrival asthe time of year when theycan hop on the snowmobile,strap on the skis or pull outthe ice-fishing gear. Othersview the onset of chilly tem-
peratures as a sign that it’s time topoint the RV south and head off for afew months in a warmer setting.
Like people, there are members ofthe bird community that savor wintryweather, and others that wing thou-sands of miles south well in advance ofplummeting temperatures. While thehuman preference for staying or leavingis a matter of personal comfort andinterests in outdoor activities, the win-ter residences our feathered friends
select is driven solely on the availabilityof food.
According to Mike Ward, Illinois Nat-ural History Survey avian ecologist andassistant professor in the Department ofNatural Resources and EnvironmentalSciences at the University of Illinois, theyear-to-year variation in our winter resi-dents depends on food supplies innorthern areas.
“Those years that seed production ispoor in the northern boreal forests
we’ll see a southern range expansion ofcrossbills, common redpolls, pinesiskins and other seed-eating birds,”
Similar in size to its cousin the Americangoldfinch, the pine siskin (Spinus pinus)has a heavily streaked body with yellow at thebase of the tail and in the wings. Pine siskinsutilize the same thistle feeders as goldfinch-es, and fluctuations in numbers aren’t areflection on your feeder but the seed popu-lations in Canada.
The smallest owl to inhabit Illinois (an inch smaller than the screech owl), the saw-whet owl(Aegolius acadicus) winters in Illinois every year but because of their cryptic coloration, infrequentvocalizations and habit of roosting in dense cedar trees, they are seldom seen. Your best chance ofsighting this visitor is to walk through an area containing numerous cedars, looking for a 7-inch owlnestled against the tree trunk. A specialist feeding primarily on deer mice, a clue to their existence maybe the pellets of indigestible hair and bone found under their perch.
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Ward explained. “Small mammal popu-lations are cyclic, and when mice andvole numbers are at their lowest upnorth we see influxes of predators,such as the snowy owl.”
While these rarities excite birdersand those closely monitoring theirbackyard bird feeders, their presencedoesn’t bode well for the birds.
“If birds haveto come this farsouth to find foodit probably meansa lot of themaren’t survivingin their naturalrange because oflimited food sup-plies,” Ward said.
The common redpoll (Acanthis flammea) also feeds like the
goldfinch. A black chin, red cap and white wing bars make for easy
identification of the occasional redpoll frequenting your feeder. A
rarer Illinois winter visitor than the pine siskin, relatively few redpolls
show up at feeders each year.
Crossbills are similar in size to the slate-col-ored junco, a common winter resident whichfrequents ground feeders. Crossbills are sonamed because their mandibles curve towardeach other and cross at the tip.
The more common of the two crossbills,and occasionally sighted in Illinois is Loxiacurvirostra, or the red crossbill. Males havea dull-red head and body and blackish wingsand tail, while females and juveniles are dullgray with hints of yellow. A highly nomadicbird, the red crossbill specializes in feedingon conifer seeds and, when present, will beseen in pine trees, not feeders.
On the other hand, in mild winters alot of birds that breed stay, which Wardsaid is to their benefit.
“If a bird doesn’t have to migrate,there is less chance that it will get lostor eaten, and, since they’ll be the firstback in the spring, they get the choicebreeding habitat,” said Ward.
What birds will the winter windsbring to Illinois this year? While somegeneral trends may be possible basedon small-mammal population cycles,you never really know what is presentuntil you venture outdoors.
December 2010 OutdoorIllinois / 17
The snowy owl (Nyctea scandiaca) differs from the owls most typically found inIllinois in two ways: Snowy owls are diurnal, or active during the day, and theyperch on the ground in open fields. Comparable in size to the great horned owl,adult snowy owls are mostly pure white. Darker, immature birds, more common-ly seen wintering farther south than older birds, are less adept at finding limitedfoods. Numbers sighted in Illinois annually vary from a couple to nearly 30, andideal viewing spots are along Lake Michigan, including Northerly Island.
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(Photo by George Oetzel, editor, On the Wing, Boulder County Audubon Society http://www.boulderaudubon.org.)
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