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As Hampton biologist Kelly McKay and Augustana College biology professor Steve Hager discussed results of the recent Christmas Bird Count, they couldn't help but talk about climate change.

The annual count of bird populations has been conducted nationally for 119 years under the auspices of the National Audubon Society. On designated days in December and January, volunteers count birds at feeders and in the field, taking note of both total number and species. Over time, the data reflects trends.

A trend McKay has observed for years is an increase of so-called semi-hardy birds in the Quad-City region during the Christmas count. These are birds that historically were borderline for normal Quad-City region winter temperatures and that previously migrated south for the most part.

Casual bird watchers know a few robins stay around all winter. But in recent years people taking Christmas Bird Counts have seen flocks of dozens.

"A lot more species are wintering way north of where they should be," McKay said. "The common yellow throat and the gray catbird are here in summer, but this time of year they should be in Central America, and we saw five of each."

And if five were observed, he said, that means many more — hundreds? thousands? — likely are hiding out throughout the Midwest, "and that shouldn't be."

He also feels certain that many or all of these semi-hardies died in the below-zero temperatures that followed in the weeks after the count.

Leland Searles, owner of an ecological consulting business who has been studying the rhythms of nature for 40 years, said he has begun to change the dates of what he used to consider normal bird migration seasons.

Ducks, geese and swans are moving north one to two weeks earlier in response to open water, Searles, based in Marshalltown, Iowa, said. Lakes, ponds and rivers are opening up sooner.

Shorebirds such as sand pipers, plovers and gulls also are arriving to fish and to find food in muddy shorelines.

The common chickadee is less abundant in the Midwest than it used to be because its population center has moved north, Searles said. He points to a 2010 report by the National Audubon Society that found that 200 species of birds have changed their population centers to the north, from as little as 30 miles to as much as 400.

Another 100 species have changed in different directions, seemingly prompted by resources (food and winter shelter) rather than temperatures.

"Climate change is actually happening and the birds show it," Searles said.

Hager said some birds are moving fast enough to keep up with changing conditions and some are not.

"It is difficult to study and predict an organism's response to climate change because not all respond equally," he said. A bird that doesn't respond quick enough, for example, might get to its summer breeding/nesting ground and find that the insects it depends on for food at the time of arrival have already emerged and died away and aren't available.

"These are just three or four of the dozens or more factors that make this  (an organism's response to changing climate) really difficult to study," Hager said. "The factors are so many we don't really know what the future holds. It's pretty scary."

What about frogs?

Another feature of this year's Christmas Bird Count for both McKay and Hager was that they heard frogs calling, a prelude to breeding season that usually occurs much later.

In December and early January, frogs generally are in hibernation. McKay said he heard spring peepers, northern leopard frogs and western chorus frogs.

In southern Illinois, he observed so many turtles sunning in wetland areas that he lost count around 300. "You shouldn't have turtles basking in December. There were grasshopper crawling around on the ground Dec. 31.

"All taxa in the environment are being affected by climate change," he said. "There's no doubt about it." A taxa is a population of organisms.

Frogs are cold-blooded creatures that hibernate in the winter, occasionally coming out when the weather warms. When it turns cold, they return to hibernation.

"I have heard frogs calling many times in the fall and winter when it is warm,"  Christopher Phillips, curator of amphibians and reptiles at the Illinois Natural History Survey of the University of Illinois, wrote in an email to the Times.

"It's not unusual at all and nothing to be alarmed about. One of the theories is that these young males are 'practicing' their calls in preparation for spring. I'm not sure there's any data to support that theory, but it sounds plausible."

But Jennifer Anderson Cruz, Iowa state biologist for the Natural Resources Conservation Service of the United States Department of Agriculture, is not so sure.

Her concern for the frogs is that "the more they come out, the more energy they use up. They can go in and out, but it takes its toll." Calling, she explained, is "energetically expensive."

If they are coming out with increased frequency, that could deplete their energy stores so when the true spring mating time arrives, they have fewer resources for calling and reproduction.

"It's not just whether they make it through the winter," Cruz said. "It's the spring. The males use their energy for calling; the females use theirs for making eggs." If they don't have enough energy they won't repopulate and their numbers will decline.

Again, Phillips of the natural history survey said he does not see a problem. "It certainly takes energy to call, but I don’t think such a small loss of energy can have far reaching negative impacts."

Hager said he, too, has heard frogs calling in winter for decades, but "it's the increase that is the difference."

Aside from the frogs' coming in-and-out of hibernation, Cruz has noticed an overall shift to an earlier breeding time in the frogs she studies, which are in Davenport.

Cruz is a Davenport native who has been studying the frogs in Nahant Marsh since 1998.

"They used to start (calling) around March 30," she said. "Now it's St. Patrick's day, a week to two weeks earlier."

When she worked in Iowa for the Department of Natural Resources, Cruz served on committees for the state wildlife action plan. What she and other members realized is that species were on the move.

Northern species of dragonflies are moving farther north and southern species are moving in to take their place, she said. "Reptiles and amphibians are too. Rare types are expanding into Iowa from the western side.

"Tree species are moving. Whether we're taking climate change seriously or not doesn't matter, the animals are moving."

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