During the Audubon’s Backyard Winter Bird Survey Feb. 8 and Feb. 9, local bird enthusiasts helped biologists track long-term trends in the state’s shifting bird population. The results of the survey will contribute to experts’ understanding of New Hampshire’s rising population of southern and northern birds and near-disappearance of some species that originally swooped in from the west.
The survey helps biologists look beyond year-to-year population changes caused by weather, said Rebecca Suomala, survey coordinator.
“Once you get past a certain point, you know you are no longer looking for an individual change that happened because of a snowstorm in one year,” she said.
Last weekend participants across the state were on the lookout for any kind of bird. They could tune in for any length of time and were asked to record the maximum number of any one species they saw together in order to prevent duplication. Guessing at a type of bird spotted was discouraged, and they were asked to only report birds they could identify. Because negative data is just as insightful as sightings, bird watchers reported even if they saw no birds.
Species ins and outs
Over the years the backyard bird survey has evolved. Before 1987, the Audubon surveyed for only a couple species of birds — the cardinal and the tufted tit mouse — because those species had begun to migrate to the state and the Audubon wanted to examine their distribution. In 1987 it expanded to include all bird types.
“Birds are very directly connected to the environment, so what happens to the environment affects their populations,” Suomala said.
Biologists have identified an increase in birds that originally lived only in southern states. These southern birds tend to prefer suburban areas where there are more bird feeders. As those areas become less common down south, the birds move north, Suomala said. Consistently warmer winters also contribute to the pattern.
The northern cardinal and tufted tit mouse never used to be here, Suomala said. But in the past couple of years they’ve migrated even farther north into the White Mountains. And other southern species are following suit. Red bellied woodpeckers and Carolina wrens have been moving in quickly.
“We had a couple of record years,” Suomala said.
Northern birds are up this year, too. Pine siskins and common red poles come south in an every-other-year pattern. It’s a matter of food supply, as trees in the north produce larger seed crops every other year “so in years when trees produce a lot of food, there is plenty of food for the red poles and they stay up north, and not as much come,” Suomala said.
One of the most startling new visitors is the snow owl, a large white bird that typically stays closer to the arctic tundra. Experts aren’t entirely sure why sightings are up, but it may have to do with a population boom last summer and a shortage of food up north this winter, Suomala said.
But it’s not all growth in the state. Biologists aren’t sure what prompted house finches and evening grosbeaks to fly west in the early-to-mid 1900s, but winter surveys have consistently shown massive declines in both. House finch numbers dropped due to bouts of conjunctivitis disease, and an outbreak of spruce budworm, the most destructive native species in northern spruce and fir forests in the eastern United States, could be to blame for killing off grosbeaks, though it’s not clear, Suomala said.
Audubon turns 100
The survey was extra special this year because the New Hampshire Audubon Society is celebrating its 100th anniversary.
“It’s a milestone not everybody gets to reach. It means a lot of people for a long time have cared a great deal about birds and wildlife — put in resources, time and commitment to those causes,” said Ruth Smith, centennial coordinator. “The work we’re doing today rests on the shoulders of a lot of people who have come before us.”
The Audubon Society has been committed to upholding the work of its 1914 founders, Smith said. That has meant dedication to both conservation and educational efforts. The Audubon’s first secretary, Manley Townsend, initiated programs for hundreds of school children. Today education remains a strong element for the organization. It now reaches about 17,000 youth through schools, summer camps and public events throughout the state.
Audubon has contributed to some major preservation accomplishments too. Perhaps most notably: In the mid 1980s, New Hampshire’s population of nesting bald eagles had virtually vanished; now, the iconic birds are back and nesting in 40 territories around the state. Last year was record-breaking.
Smith remembers the strange story of the eagle’s return: “When the first eagle pair came back to nest in 1999, they returned to same exact tree that the last eagles had been in in 1949. The fact that the tree was still there and the land was protected made a difference. Audubon had a part in that. It captures the sense of importance of our work.”
As seen in the February 13, 2014 issue of the Hippo.