Now that Joan Walsh has mapped out the bird species in Massachusetts, the question is what to make of the aviary she’s revealed. She is the director of bird monitoring at Mass Audubon, which this month released “The State of the Birds 2013” and the “Massachusetts Bird Breeding Atlas 2.” Taken together, the studies tell a story that calls for simultaneous celebration and concern.
On the positive side, 60 percent of Massachusetts bird species have increased their numbers in the last three decades, benefiting from a century’s regrowth of rural forests and suburban tree canopies, and from wetlands and clean water conservation efforts inspired by Rachel Carson’s 1960s “Silent Spring.” But the more recent dicing up of grasslands and woods for new suburban developments has 40 percent of species on the decline.
“This is not a story of doom and gloom,” Walsh said. “We are doing a lot right in this state. . . The big message is resilience. If we give the birds a chance, they will do well.” But she urged that while most declining birds are “not yet on life support,” they still need “immediate supervision.”
Colorful birds doing well include red-bellied and pileated woodpeckers, pine warblers, and Eastern bluebirds. Bald eagles, peregrine falcons, and osprey have reappeared in the skies. Great blue herons, once hunted for plumes to the point of near extinction, line inland rivers and coastal marshes. Ruby-throated hummingbirds swarm feeders. Some proliferating birds have become annoying, from park-pooping Canada geese to Brookline’s brazen wild turkeys.
The gorgeous birds that are fading away include the American bittern, Eastern meadowlark, American kestrel, ring-necked pheasant, cliff swallow, Northern bobwhite, and roseate tern. Losing those birds will rip gaping holes in the mosaic of bird life in Massachusetts.
“The State of the Birds 2013” and the “Massachusetts Bird Breeding Atlas 2” are the result of tens of thousands of hours of observations in 10-square-mile blocks by more than 700 volunteers from 2007 to 2011. “Atlas 2” compares bird life in the Commonwealth to that depicted in an earlier atlas completed in 1979.
The changes in bird life poignantly overlap with another major study this year from the Harvard Forest and the Smithsonian Conservation Biology Institute. That study found that New England as a whole is back to 80 percent forest or woods. But David Foster, director of the Harvard Forest, said there were warning signs for Massachusetts, in particular. Development has reduced forest cover from nearly 70 percent four decades ago to closer to 60 percent today.
“You don’t want to bask in the glory of environmental accomplishment,” Foster said. “We are seeing patterns of forest fragmentation and perforation that may make many birds reject habitat that might look perfectly suitable to us, but for the birds is not large enough, thick enough, or missing critical shrubs underneath.”
Birds that increasingly like Massachusetts and its recent milder winters include more southerly warbler species and the Carolina wren. The wren, which bred almost exclusively in Southeastern Massachusetts in the 1970s, today breeds over the entire state.
Cooper’s hawks, which had been killed by pesticides and farmers angry over the birds’ pilfering of poultry, have exploded in numbers. One blizzard day, as I wrote in my home in Central Square, Cambridge, I felt a concussive “whoomp!” through the living-room window. A Cooper’s hawk had just blown apart a pigeon that was at my feeder.
Conversely, the Eastern meadowlark, which once bred over 4,500 square miles of land in Massachusetts, now breeds in only 1,000 square miles. Much of the land that was vacated is in the Interstate 495 crescent. This golden-breasted bird was afflicted by pesticides, loss of farmland, livestock grazing, and hayfield cutting on the farms that remain, which destroyed nests on the ground.
“It’s a bird that will likely require complex human interventions to thrive again,” Walsh said. “Can we get farms to cut their hay out of breeding season? Can consumers support small farmers who don’t use pesticides? Can we promote any expansion of grassland when opportunities arise?”
The meadowlark is a reminder that maintaining a full mosaic of breeding birds in Massachusetts requires a variety of management solutions. Brown thrashers might need more shrubland. Cliff swallows might need more artificial nest ledges. American bitterns may need even cleaner water and more cattail wetlands free of invasive species. Many birds would do better if people kept cats inside. The Smithsonian Conservation Biology Institute this year found that home-owned, stray, and feral felines kill between 1.4 billion and 3.7 billion birds a year.
Remedies remain mysterious for other birds, such as the American kestrel, whose decline was noted by many of the volunteers whose work is chronicled in the atlas. The cause of the decline is unclear, but chemicals and the loss of nesting sites have probably played a role.
“The birds, whether they are doing well or not so well, are sending us a strong signal as to how we are managing our environment,” Walsh said. “People have to decide what kind of landscape they want.” If we want the song of the meadowlark to join the screech of the eagle, and the bittern to wade alongside the blue heron, we will have to wade deeply into the issue ourselves to secure the best environment for the most birds.