Winter Birds are Arriving in the Northeast
Northern Birds are Entering Connecticut
Seasonal changes are heralded by distinct changes in bird populations. Some birds migrate in anticipation of the season. Others wait until the season has matured before showing up. With almost weekly arrivals and departures of species, a diligent observer does not have to look at the calendar to know what month it is.
Other Seasonal Changes
Besides population changes, birds exhibit other clues that indicate winter has arrived:
1. Behavioral changes.
- Winter birds do not nest or attend young. Exceptions to this are the larger owls.
- Gulls begin to drop and feed on clams and snails.
- Autumn song tapers off – but may still be heard on warm days.
- Chickadees, titmice, robins, and mockingbirds forage for berries, seeds, and suet instead of insects.
- As heavy snowstorms approach, birds of the far North often cluster in the lower branches of thick evergreen trees where they survive under an almost solid tent of snow.
2. Phenetic plumage variations.
- Gulls lose their pure white heads and become mottled.
- Loons and grebes become a nondescript brown with beige underbellies.
- Starlings display brightly speckled tips on iridescent black feathers.
- Many ducks sport non-breeding, eclipse plumage.
- The brilliant male goldfinches are an olive-drab with slightly darker wings this time of year.
3. Distribution differences.
- Dabbling ducks move to salt water as lakes and ponds freeze.
- Coopers and sharp-shinned hawks move out of the woods and visit bird feeders for prey.
- Crows and ducks are found in groups during the day and often roost in rookeries (crows) or flock in rafts (ducks) containing tens of thousands of birds. Blackbird and starling flocks sometimes number in the millions of individuals.
- Winter herons, when found, are solitary.
- Montaine birds often descend into valleys where conditions are more favorable.
Some Species are Unpredictable
Crossbills are highly specialized for feeding only on conifer seeds, but a given forest often produces a massive crop in one year, and almost completely forgo cone production for several years after. Crossbills must search widely for productive forests and are usually common in years of plenty and completely absent in other years.
Snowy owls feed primarily on boreal rodents. After winters of plenty, these owls produce larger than usual numbers of offspring. But feeding these extra young puts extra pressure on rodent populations and during the subsequent winter, prey are usually scarce. In response, these far northern owls migrate south and can often be found in fields and along beaches of the Northeastern and Midwestern states.
Evening grosbeaks exhibit similar patterns of irruptive occurrence, but the causes are less understood. Flocks of ten to fifty birds will appear at a feeding station one day, stay for a week or more, then disappear – even though the station may be well stocked.
Some Species Differ Across Their Range
Hooded mergansers regularly visit the same areas during the winter months. this species' unpredictability lies in its plumage. In the Northeast, hooded mergansers share winter grounds with equal or greater numbers of congeneric red-breasted mergansers. Here, the males display their breeding plumage all year. In the western states, where there are fewer congeners, hooded males molt to a cryptic eclipse plumage for winter, looking much like females.
Winter birds are a pleasure to watch because of variety in species, behaviors, distributions, and plumages. Watch for them, enjoy them, and see what new things you can learn about them.
White-throated Sparrow on Winterberry Holly
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