Birds aren’t flocking to backyard feeders this winter

February 13, 2012 under CANR News

What’s in short supply this winter? If you said snow you guessed the first (and obvious) answer. But you may not have noticed what else has been scarce — birds at backyard feeders.

“Our customers are talking about the fact that fewer birds are coming to feeders this winter,” says Charles Shattuck who, with his wife, Kathy, owns Wild Birds Unlimited in Hockessin. “I’ve heard reports of fewer birds at feeders across the East Coast.”

Although no one can say exactly why birds are staying away, Shattuck has a hunch that lack of snow and mild temperatures are at least part of the reason.

When Shattuck takes a walk through his 14-acre property, he sees plenty of birds in bushes and brambles. But not so many at the feeders, seed logs and suet feeders near his deck and kitchen windows. “Think about this past Wednesday, when it was 60 degrees,” says Shattuck. “The birds can still find bugs to eat when it’s that warm. They don’t need to come to my suet feeders.”

“It’s been a very light winter in terms of bird activity at feeders,” concurs Derek Stoner, an avid birder and naturalist at the Delaware Nature Society. “The big flocks of songbirds — sparrows, juncos, cardinals, titmice, chickadees — are around, but they are dispersed widely. Since we’ve not had extended periods of cold or snow cover, the birds have been fine and doing well with what nature provides.”

When northern Delaware did have a light dusting of snow Jan. 21, the birds decided to pay Shattuck a visit. “Even a small amount of snow drastically changed the activity level at my feeders,” he says.

Several northern species, like red-breasted nuthatches and pine siskins, haven’t arrived in Delaware at all – probably because weather conditions and food supply have been adequate in their breeding grounds in the boreal forests, says Chris Williams, a University of Delaware associate professor of wildlife ecology.

“Pine siskins sometimes appear in Delaware in great numbers; this kind of irregular migration is known as an irruption,” says Williams. “We had such an irruption in 2009.”

The fact that some northern species are staying away and resident birds are staying in the woods and fields doesn’t bode well for the Great Backyard Bird Count. A joint project by Cornell Lab of Ornithology and other partners, the count has become one of the largest citizen-scientist efforts in the nation. This year’s count starts Feb. 17 and concludes Feb. 20 and provides a real-time snapshot of where birds are across the U.S. and Canada.

Last February, 11.4 million birds were counted. This year’s numbers could be lower unless more participants venture out of their backyards. Any bird sighting can be reported to the Great Backyard Bird Count, not just those in the backyard.

“Last year, I saw a common merganser in the Red Clay Creek and vultures in the supermarket parking lot and included both on my checklist,” says Shattuck, who has participated in the count for eight years. His store, along with Wild Birds Unlimited’s other franchise stores, co-sponsor the count.“You can count birds at a park, go on a guided hike or simply make note of birds in a parking lot – any bird seen during the four days of the count qualifies,” he says.

Williams says he believes that the count offers useful data for ornithologists.  Bird populations are dynamic and constantly in flux. No researcher or team of researchers working alone could document the distribution and movements of so many species the way the Great Backyard Bird Count does, he says.

Solny Adalsteinsson is a graduate student in Williams’ research group and a self-avowed “bird nerd.” Growing up in Wilmington and later Kennett Square, Pa., she enjoyed the blue jays, northern cardinals and white-breasted nuthatches in her backyard in wintertime. As an undergraduate at Penn State, she liked to hike in the mountains and look for common ravens, which aren’t found in Delaware.

When she worked in Kauai, Hawaii, in 2009 and 2010, the seasonal shift in birds was subtler. “Many seabirds spend their lives out on the ocean and return to land only to breed so the return of the Laysan Albatross is a sign of ‘winter,’” notes Adalsteinsson. “In November, the albatross pairs return to their nest sites on Kauai and begin their courtship dances, sometimes right in residents’ backyards.”

You’re not going to spot albatrosses in Delaware but there are plenty of other interesting birds you might see if you join the Great Backyard Bird Count.

A screech owl, yellow-bellied sap sucker and brown creeper were on Shattuck’s tally sheet last year. Other birds spotted in Delaware during the 2011 count include a peregrine falcon, orange-crowned warbler and Baltimore oriole.  More frequently spotted birds were common grackles, red-winged blackbirds, dark-eyed juncos and white-throated sparrows.

To register for the Great Backyard Bird Count, or for more info, go to this website. While you’re there, print out a regional bird checklist to help identify what you see. There also are many good bird identification apps to figure out what you’re looking at, says Shattuck.

Learn more:

Breakfast and the Great Backyard Bird Count, Feb. 17, 8 a.m.-11 a.m. Help count birds and enjoy breakfast, too, at this program at Ashland Nature Center. To register, call 239-2334.

Article by Margo McDonough

Photo by Derek Stoner

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Colossal flocks of blackbirds are a common wintertime phenomenon in Delaware

December 8, 2011 under CANR News

If your holiday shopping takes you to Christiana Mall, time your drive for a half hour before sunset. That’s when you’re most likely to see a massive flock of black birds winging its way to Churchmans Marsh.

This flock of several million birds forms a solid black carpet in the sky; if it was earlier in the day, when the sun is higher, the flock would blot it from view.  The mixed flock consists of true blackbirds (red-winged, specifically) but also common grackles, brown-headed cowbirds and starlings.

“It’s an amazing spectacle,” says Derek Stoner, past president of the Delmarva Ornithological Society. “The sky is filled with birds returning to roost in the marsh after a day of feeding. You get the very best views of this super flock around the intersection of Route 7 and Churchmans Road — as long as you time it right.”

A flock of blackbirds so colossal that they block the sun sounds like something straight out of Hitchcock’s thriller, The Birds, but it’s a common wintertime phenomenon in Delaware.

“The unique combination of Delaware’s marshes and the surrounding agricultural lands are what make the state an attractive winter residence for millions of blackbirds,” says Chris Williams, a University of Delaware associate professor of wildlife ecology. “You’ll also see this winter flock phenomenon in New Jersey, coastal Virginia and North Carolina, and other coastal regions in the South.”

The Churchmans flock is one of about a dozen winter flocks in Delaware, according to Williams. Each morning the flock splits up and disperses in search of food, including such things as corn stubble or seedy grass. Depending on food availability, the Churchmans flock may travel to Chester County, Pa., or as far as Lancaster before returning to its nightly roost in the marsh.

Blackbirds only form super flocks in winter, says Williams. By March, the flocks will disperse to set up nests and begin breeding. Some of the birds in the super flocks are year-long Delaware residents; others migrate here from Canada and other northern latitudes.

As to why a bird would decide to hang out with millions of other birds each winter, scientists have several theories, says Williams. One possible reason is that a flock provides better protection from predators. Each bird in a massive-size flock doesn’t have to be quite as vigilant as it would be if it was flying solo.

A large flock also creates the conditions for “predator confusion.” For the same reason that fish swim in schools, birds fly in flocks. It can be difficult for a predator to pick out individual prey in large groups. “All the birds massed together create sensory overload for the predator,” notes Williams.

In addition, the dilution effect occurs when there is a large flock. Simply put, this means that the mathematical odds that a bird will get eaten are smaller when the flock is larger.

A large flock also promotes greater feeding efficiency because the birds share information about food sources. “Blackbirds are known to be great communicators,” says Williams.

Although Williams is awed by the Churchmans flock as it wings its way over his Newark neighborhood, heading out for food, he dreads the inevitable February day when 20 or 30 birds will drop down from the flock and take up residency in his backyard.

“I keep feeders up all winter long and enjoy seeing a variety of birds at the feeders,” says Williams. “But all of sudden, in February, a small group of blackbirds will break off from the large flock overhead, descend on my feeders and eat all the seed in minutes.”

“Even if I take the feeders down, the birds stick around,” adds Williams. “Blackbirds in the backyard are a sure sign it’s mid-winter.”

Article by Margo McDonough

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Wild animals cope with harsh winter weather

February 10, 2011 under CANR News

Humans may whine about the harsh weather but for most of us winter isn’t a matter of life or death. For many wild animals and birds, the stress of winter is life-threatening. Wild animals and birds must contend not only with extreme weather but with a lack of food and other resources, such as adequate shelter.

Winter adaptations vary by species. Some species migrate, some go into dormancy and some develop a thick skin and tough it out. The thick skin is literal — from the bushy cold-weather undercoat of the fox to the thick winter coat of the raccoon.

Many birds adapt to winter by getting the heck out of here. About half of Delaware’s common summer birds are migratory and depart for warmer climes each autumn, according to Chris Williams, a UD assistant professor of wildlife ecology in the College of Agriculture and Natural Resources.

The birds that do stick around Delaware often form flocks in the winter, comprised of members of the same species, or sometimes flocks of different species (known as mixed flocks). Common mixed flocks include small birds, like chickadees and titmice, which join larger birds, such as nuthatches and woodpeckers.

Flocking is a form of cooperative behavior that rarely occurs during spring and summer nesting season. Williams says that flocking can increase wintertime avian survival rates. Flocks have an easier time securing food since birds are foraging together. And when flocks roost together, heat loss is reduced. Flocking also can provide safety in numbers from predators.

Birds utilize a number of other survival strategies in winter, such as fluffing their plumage, which creates an insulating layer by trapping air. They cope with the cold by shivering, just like we do. And many species increase their metabolic rate to produce more body heat. The downside of this adaptation is that they need to eat more food, even though food supplies are limited.

A handful of species lower their metabolism, but only in the evening when food isn’t available. These birds enter a state called torpor, which causes lowered body temperature and decreased oxygen consumption.

Plenty of mammals also slow their metabolic rate in winter. Groundhogs that live in northerly climes are “true hibernators,” meaning they exist in a state of uninterrupted, deep sleep for six to seven months, with body temperatures so low their metabolisms are almost at a standstill.

However, Delaware’s groundhogs are “semi-hibernators,” says Derek Stoner, conservation coordinator at the Delaware Nature Society.

“In February and March, if it warms up to about 50 degrees, Delaware groundhogs will come out of their burrows,” says Stoner. “By St. Patrick’s Day, the males, in particular are very active on warm days. They visit other burrows in hopes of finding a mate.”

In the fall, Delaware’s groundhogs gained some 50 percent of their body weight to prepare for their long — if somewhat fitful — snooze. But they also stashed grass in their burrows for the occasional snack when they do awake. Chipmunks also are “semi-hibernators” at Delaware’s latitude.

Deer don’t hibernate in winter although they do move around less to conserve energy. In cold conditions, they gravitate to areas with good thermal cover, such as a patch of evergreen trees that’s protected from the wind and cold and thus a degree or two warmer than surrounding terrain.

In the Poconos and Adirondacks you can see herds of several hundred deer hanging out together in the woods. Here in Delaware, herds are smaller, usually about 40 deer. Stoner says that a herd has congregated on Coverdale Farm, near Way Road, for the past several weeks.

Like flocking behavior in birds, herding is a wintertime phenomenon that increases survival rates. Come spring, the herd breaks up and the deer will go their separate ways.

Unlike us, wild animals and birds don’t need to turn to the Weather Channel to know when a storm is brewing; they sense the shift in barometric pressure, says Stoner. While we make our pre-storm trip for milk, bread and eggs, they, too, make a mad dash for adequate provisions before the snow flies.

Article by Margo McDonough

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