Milder autumns up north mean fewer birds for the annual Audubon count

A half hour before sunrise in Felts Audubon Preserve, Kathy Doddridge heard a familiar call.

Hoo-h’HOO-hoo-hoo.

Then she saw the source.

“Hooting great horned owls is always a great way to start the day,” she said.

There’s still about a week left to collect data for the 118th annual National Audubon Christmas Bird Count, a long-running event for citizen scientists to tally birds started by ornithologist Frank M. Chapman on Christmas Day in 1900. Today, the event ranges throughout North America, parts of Central and South America, and as far as Guam.

The Bradenton Circle, which covers an area west of Interstate 75 from Moccasin Wallow Road in Palmetto to Long Bar Point south of Cortez, has already tallied its findings.

Hurricane Irma may have blown down birds’ habitats, but it’s the changing weather patterns that most likely are having the biggest effect.

Doddridge was in charge of compiling the data of the circle’s bird count, which included 73 volunteers scouring 13 areas by car, foot, boat or golf cart. More than 29,000 individual birds were seen, which is a 13 percent decline from last year.

Nine species were added to the list — including a ruby-crowned kinglet, summer tanager and red knot— but six species, such as the least bittern or chipping sparrow, that had been spotted last year weren’t seen this time around.

“If you have milder fall or winter in the north, you’re not going to get all the birds you would normally see pushing southward,” Doddridge said.

This is because some are likely to stick around because it’s still warm in their summer ranges, as the University of Nebraska-Lincoln saw with migration data on whooping cranes.

Fewer wood ducks, roseate spoonbills, great horned owls, eastern bluebirds, American robins and American goldfinches were counted by the Bradenton Circle this year.

This was concerning to Steve Black, who led the count in the southeastern portion of the circle around Jiggs Landing, Lincoln Road and Tara Preserve Lane.

“There were many, many less birds and it was kind of scary,” Black said.

In previous years, even if the day of the count was colder or rainier there were still birds, Black said. This Dec. 16 morning was “gorgeous” and “terrific,” and yet ducks and vultures were harder to come by. Doddridge said she suspected that because of the more recent cold front, more birds would be heading our way in time for Sarasota’s bird count on Saturday.

Black said he doesn’t think climate change has had any effect on the kinds of birds he has seen over the years (“Audubon doesn’t agree with me,” he said.), but he thinks habitat destruction by way of increased development has a bigger consequence.

The Birds and Climate Change Report put out by Audubon in 2015, which used data from the Christmas Bird Counts and North American Breeding Bird Survey, identified 314 species that are expected to in some way be affected by climate change. A little more than 70 percent of the species the Bradenton circle saw this year are classified as climate endangered or threatened by Audubon.

For example, according to Audubon’s climate model, the brown pelican could lose 54 percent of its winter range by 2080. While the osprey can live year round in Florida, it’s expected to lose 79 percent of its summer range later in the century.

The common thread of how shifting climate could affect these species is that their winter ranges are slowly crawling north. This means that some migrating birds may not fly as far south.

A study published in Nature earlier this year suggests that climate change also affects when birds head back north in spring. Some species, such as the great crested flycatcher and indigo bunting, weren’t able to shift their spring arrival times. In the western U.S. where researchers found that plants sprouted later than usual, birds could arrive too quickly, meaning lack of warmth and food; in the east, when plants grew earlier than normal, some birds arrived to their breeding grounds late. This could have a major skew on reproduction and nesting, the study suggests.

Audubon Florida’s interim executive director Julie Wraithmell said Florida was unique in that it has both year-round and wintering species, and Bradenton in particular was “remarkable” in its range of habitat. But the shift in birds’ winter ranges is expected to continue.

“That could make for some interesting numbers, both in abundance of species and in the diversity of species we see in this count,” Wraithmell said.

This story was originally published December 29, 2017 at 4:01 PM with the headline "Milder autumns up north mean fewer birds for the annual Audubon count."