Birds in Transition
April 23, 2016 at 6:06 am (birds)
Tags: Canada goose, Cooper's hawk, eastern bluebird, eastern phoebe, great horned owl, hooded merganser, nest, northern cardinal, red-tailed hawk, song sparrow, St. James Farm, yellow-rumped warbler
by Carl Strang
Soon the first wave of birds that overwintered in the tropics will reach northern Illinois. April has brought a transition from wintry weather to the warmth, plant growth and insects that make the trip worthwhile for the many species whose ancestors were content with tropical conditions.
For most of the month we see birds that are year-round residents or are newly arrived from their wintering grounds in the southern states. They have to deal with the season’s variability, though. Early in April a cold spell brought a thin snowfall. There still were insects to be found, but they were on or close to the ground. A selection of species foraged on the banks of the stream at St. James Farm Forest Preserve.
These included an eastern bluebird that abandoned his practice of hunting from tree branches, and shifted to hopping around in the open.
The preserve’s first yellow-rumped warbler of the year also searched for prey there, though such bank foraging is a common practice for that versatile species.
Even an eastern phoebe was forced to a ground-foraging interval.
On other days, getting set for the nesting season was a priority.
Cooper’s hawks occasionally called in wooded areas, considering whether to nest at St. James Farm.
Song sparrows sang as they began to sort out their territories.
Cardinals have been singing since January, as they are the songbirds most sensitive to day length change.
Pairs of hooded mergansers hung out on ponds where there are nest boxes.
The preserve’s red-tailed hawks completed their nest and were good to go.
A second pair of geese chose St. James Farm for nesting, but their site is a risky ridge beside the stream, with water on each side but reachable from either end by a coyote.
April 21 was warm enough that the great horned owl young did not need brooding. This was my first look, and I could not be certain there was more than one baby.
And now, with the warm days forecast ahead, the big push of migrants soon will diversify the preserve’s avian picture.