Survey of Rhode Island breeding birds finds surprising results

            Three years into a five-year project to document the distribution of breeding birds in Rhode Island, and volunteers are turning up some rather unexpected results. Nearly a dozen species have been found to be breeding in the state that were not recorded during an identical effort 31 years ago, and some of those discoveries are quite surprising.

                Charles Clarkson, coordinator of the Rhode Island Breeding Bird Atlas, said that bald eagles, common ravens, black-throated blue warblers, and yellow-bellied sapsuckers all breed in at least two locations in the state, although they were not found in Rhode Island during the previous

Yellow-bellied sapsucker

survey. In addition, volunteers documented the first occurrence of breeding Kentucky warbler, black vulture, common eider, pied-billed grebe, yellow-crowned night heron, black rail and chuck will’s widow.

                Clarkson said the yellow-bellied sapsucker is especially noteworthy.

                “That really took me by surprise because I wasn’t expecting to ever find it breeding here,” Clarkson said. “Their traditional breeding range doesn’t come anywhere close to Rhode Island. The closest they usually come to breeding here is in western Pennsylvania and New York.”

                The Breeding Bird Atlas divides the state into 165 blocks, each 10 square miles in size. About 170 volunteers work to document all of the bird species that breed in each block. The program is sponsored by the University of Rhode Island and the Rhode Island Department of Environmental Management.

Yellow-bellied sapsuckers have so far been found breeding in two blocks, bald eagles in six blocks, and common ravens in 20 blocks. A total of 167 species have been recorded as possibly, probably or confirmed breeding in Rhode Island, three more than were recorded during the first atlas. The most widespread species are the American robin and gray catbird.

                “When all these volunteers get out in the woods looking for birds, they tend to find things that aren’t usually noticed,” said Clarkson.

                The common raven, bald eagle and black vulture were not unexpected birds to be added to the state’s list of breeding species, since they have been seen in increasing numbers in the last decade. But the black rail, a small, secretive chicken-like bird that breeds in marshes and wet meadows and vocalizes almost exclusively at night, was another surprise.

                “They’ve been declining range-wide, so that gives us a glimmer of hope for the species,” Clarkson said.

                Among the other notable findings was the growing number of pileated and red-bellied woodpeckers breeding in the state. Pileated woodpeckers, the largest member of the woodpecker family in the United States, were found in just two blocks during the first atlas in the 1980s, but it has been recorded in 35 blocks so far in the present project. The distribution of the red-bellied woodpecker increased from 4 blocks to 88.

                “We’ve had a massive increase in distribution for those species, and the reason for their growth is very different,” said Clarkson. “In the case of the pileated, it’s a result of the natural succession of its wooded habitat – they like older forest habitat. For the red-belly, it’s a slow persistent expansion of its range northward, primarily due to climate change.”

                Osprey numbers have also increased dramatically from 14 blocks during the first atlas to 50 blocks today. Clarkson said the increase in nesting osprey is due to the banning of the pesticide DDT in the 1970s, which had caused widespread reproductive failure in the birds in the 1950s and 60s.

                On the downside, several species documented 31 years ago as breeding in Rhode Island have not been found during the first three years of the current atlas project. These include northern bobwhite, magnolia warbler, green-winged teal, common gallinule, upland sandpiper, yellow-breasted chat and long-eared owl.

                “Most of those are species that I’m not surprised we haven’t found yet,” Clarkson said. “The majority of them were not found here in big numbers during the first atlas. Some of them may still have breeding populations in the state but they’re at low enough densities that we just haven’t found them yet. We still may find them.”

                The species with the steepest decline is the purple finch, which was recorded in 76 blocks during the first atlas but in only 11 blocks during the current atlas.

                “It could be that there is an actual decline in the species brought on by habitat loss or competitive exclusion with the related house finch,” explained Clarkson. “We know they have been in decline in the eastern portion of their range where they overlap with house finches. But it could also be misidentification by our volunteers.”  The two species can be difficult to tell apart.

                Volunteers for the Rhode Island Breeding Bird Atlas will continue to collect data for two more breeding seasons. They are also collecting information during other times of the year about species that winter in the Ocean State or migrate through the region.

This article first appeared on EcoRI.org on February 21, 2018.