Sanctuary Breeding Birds Monitoring

Red-winged blackbird © Eric Hayward
Red-winged blackbird © Eric Hayward

The birds that inhabit Massachusetts can be put into categories depending upon the times of the year they are present.

  • Those that visit the Commonwealth only during migration, breeding further north in New England or Canada and spending the winter in more balmy climates.
  • Those that spend the winter with us, but migrate further north to the forests of Canada and the Arctic tundra to raise their young.
  • Those that build their nests, lay eggs, and raise their young in Massachusetts.
    • Some of these breeding birds, such as our state bird (the black-capped chickadee), are in Massachusetts year-round.
    • Others, such as the piping plover, spend the winter in the south and migrate to the Commonwealth to breed.

When Do Birds Breed?

Most birds in Massachusetts begin nesting in mid to late spring, with the most intense breeding activity occurring in June. If successful, young hatched in June will fledge (leave the nest on their own power) by the end of June to mid July.

Most birds will nest only once a season. Birds whose nests, eggs, or young are destroyed by predators or storms may attempt to raise a second or even a third brood.

Identifying Breeding Birds

Nesting generally requires an undisturbed, hidden location, since the eggs and young are very vulnerable to nest predators, such as raccoons, squirrels, jays, and crows. As a result, nests hidden among the upper branches of a tree or tucked in among dense grasses in a meadow can be hard to find.

Scientists who survey breeding birds rely on indirect means to infer that birds are nesting. The presence of singing males, who vocalize to let others of their species know that their territory is occupied, is a reliable indicator that nesting is occurring nearby. Our breeding bird surveys rely heavily on seeing or hearing singing birds.