Illinois hunting and fishing

A black and white warbler—this bird was banded during 2010—was one species to arrive early this spring. Photos by Chris Young.

Warm weather has spring migration out of sync

March 30, 2012 at 07:29 AM

With spring in fast-forward this year, birders are wondering if migration will run ahead of schedule, too.

“For the most part, it’s single, individual birds so far,” says H. David Bohlen, assistant curator of zoology at the Illinois State Museum. “The main thrust of migration is not here yet.”

Bohlen says he saw a black-and-white warbler in Sangamon County on March 21, a full week ahead of the earliest date he has recorded for the species in his 40 years of studying central Illinois’ birds. A few species of shorebirds also have arrived early, Bohlen says.

But for the most part, birding is slow.

What concerns Bohlen is how quickly trees have bloomed.

“A lot of birds probe those flowers,” he says. “They might not be able to find the right kinds of insects (if the leafing-out and blooming period is passed before migrants arrive).”

Vern Kleen, retired ornithologist and board member of the Illinois Audubon Society, was setting up nets for the first day of spring bird banding Tuesday at Adams Wildlife Sanctuary, 2315 Clear Lake Ave.

Illinois hunting and fishing
A song sparrow is one of the first birds banded at the Adams Wildlife Sanctuary.

“It’s a mixed bag,” says Kleen of birds arriving in central Illinois outside of their normal migration times. “On one hand, the birds could show up early, but then the question is, would they find any food? And on the other hand, they could migrate according to their normal pattern and find the insects have come out too early.”

‘Something really odd’

Kleen, along with Lincoln Land Community College biology professor Tony Rothering and student Nate Hoyle, captured a robin, two cardinals and a song sparrow during a check of the nets at mid-morning.

Illinois hunting and fishing
Lincoln Land Community College biology professor Tony Rothering (standing) and student Nate Hoyle remove a bird from a net at the Adams Wildlife Sanctuary.

The bird banding project documents what kinds of birds take advantage of urban sanctuaries like Adams during the spring and fall.

Kleen says birds migrate more in tune with the “photo period,” or hours of sunlight each day.

When everything is in sync, birds arrive just as insects emerge, and Bohlen says he fears birds could arrive after caterpillars and other prey have peaked.

“I think they are going to go right on past us (if the food is not available),” he says. “I don’t recall in my 40 years a week in March with temperatures in the 80s.

“I think it is something really odd.”

Bohlen says warm weather has altered routines for both birds and people.

Pleasure boaters are out early on Lake Springfield, and Bohlen says waterfowl using the lake don’t normally have to share the lake with boats just yet.

“The coots and ruddy ducks have been run ragged by boats,” he says.

Bohlen asks boaters to be aware of both migrating and resident birds — like a pair of bald eagles that built a nest on an island just off Marine Point — and give them some space.

No matter when birds arrive, Bohlen says, birdwatchers are going to find the going tough. Trees normally don’t leaf out completely for a few more weeks. All that greenery is going to make spotting migrants difficult.

“They will be hard to see in all that dense foliage.”

Chris Young can be reached at .(JavaScript must be enabled to view this email address) or 788-1528.

Arctic Oscillation

People asking, “What’s up?” with the weather this winter should look up — high up in the stratosphere above the Arctic.

The Arctic Oscillation is a ring of air circling counterclockwise six to 30 miles above the Arctic during the winter months.

When winds are strong, they keep frigid air confined to the Arctic. This is called the positive phase.

When winds weaken during its negative phase, cold air masses can push southward, bringing colder conditions, snow and storms to mid-latitudes.

In recent years, the Arctic Oscillation has tended to remain in its positive phase according to the National Oceanographic and Atmospheric Administration.