Fewer birds counted

Tuesday, December 27th 2011. | Science News

Temperatures for December have been surprisingly warm this year, but it may not have meant bigger numbers for the 112th Annual National Audubon Society Christmas bird count.

christmas birdResults locally may even show the opposite.

“The counts conducted so far have generally been finding numbers of many common species are relatively low,” said birder Charles Caron, who heads up a group of people counting birds in Westminster. “I believe that this is a result of very low natural food supplies this year.”

Mr. Caron, who was counting yesterday, said it is his experience that bird distribution in the winter is almost entirely a function of the availability of food.

He said weather can affect food availability, including in the spring. Good weather might mean more abundant food for birds in the early winter. Bad weather in the winter could also tend to concentrate birds in better habitats or near feeders.

But it is the food supply that drives bird numbers, he said.

This year, as birders do the Audubon count between Dec. 14 and Jan. 5, the mild weather could mean birds are more spread out and more difficult to count, Mr. Caron said.

The Audubon count was founded in 1900 by Frank Chapman as an alternative to what had been a holiday tradition of the Christmas side hunt. The side hunt was a competition to see who could kill the most birds. Mr. Chapman, an ornithologist with the American Museum of Natural History, proposed an alternative where people would go out and count, rather than kill, birds.

The side hunt is no longer held but the bird count continues, with 62,000 people taking part last year in 2,215 count circles throughout the country, Canada and Latin America. This and earlier counts have provided data for hundreds of scientific studies and the bird count is the major basis for the annual U.S. State of the Birds report.

Among the findings of the count have been that Eastern finches have been moving farther west for the past 60 years and, over 40 years, many North American birds have been shifting their winter ranges north and inland.

Counts within individual count circles are held on a single day, with data also accepted on sightings during the count week, which is defined as three days before and three days after the count day.

In Athol and surrounding communities, 13,756 birds of 62 species were counted on Dec. 17. David Small, president of the Athol Bird and Nature Club, said there were a handful of surprises for the 40 birders and nine feeder watchers who tallied birds for the Athol count circle.

For the first time in the 44-year history of the Athol area count, a double-crested cormorant was seen in the North Quabbin area. The cormorants are sea birds that had declined owing to the use of DDT in the 1960s, but have significantly increased in the years since the insecticide was banned. They tend to winter along coasts, but this year some may have moved inland because of a lack of ice on lakes and ponds.

Also seen during the Athol-area count was an American kestrel, a hawk seen only one other time by Athol birders during Christmas bird counts; and a Lapland longspur, for only a fourth time.

Mark Lynch led the bird count this year in Sturbridge. He said the 77 species counted was average for the Sturbridge circle, and the number of birds, 15,501, was low for the count.

“I think many of us were expecting more species with the mild temperatures and lack of snow, but land birds were in short supply,” he said.

Missing from the count for the first time was the horned lark, and there were low numbers of ruffed grouse, the numbers of which have been declining throughout the history of the count. There were two new species recorded, five gadwalls and a sora.

Birder Strickland Wheelock will lead a count in the Uxbridge area on Saturday. He said people looking to participate should contact him at skwheelock@yahoo.com.

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