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Breeding Birds of the Bull Run Mountain

The Wood Thrush (Hylocichla mustelina)

The wood thrush breeds in eastern North America from Canada south to Northern Florida. Over the last few decades it has declined over most of its range due to habitat loss here and in its Central American winter range. Cowbird parasitism also plays a role in the decline during the breeding season. Here in the Bull Run Mountains, the liquid flute-like song can still be heard in the deep woods. It has been described as chimes echoing in a cathedral, ethereal, and one of the most beautiful thrush songs. Thoreau wrote, "Whenever a man hears it, he is young, and Nature is in her spring; wherever he hears it, it is a new world and a free country, and the gates of heaven are not shut against him."

Beginning at daybreak, males may sing until well after sunset. The woods are silent now but by late April, these handsome songsters will be back. Once the male stakes out his territory and finds a mate, nest building will begin. Nests are made of grasses and weed stalks with a middle layer of mud. They look like robins' nests except for the presence of dead leaves and sometimes moss. Also, while the robin lines its nest with dried grass, the wood thrush lines its nest with brown rootlets. The nest is usually placed in a fork of a sapling or sometimes saddled on horizontal branches. The nest can be anywhere from 6 to 50 feet above the ground, but is usually between 6 and 12 feet. The male sings and defends his territory while the female builds the nest alone.

In it she lays two to five unmarked eggs. They are pale blue to bluish green in color, and after being incubated only by the female, they will hatch in 13 to 14 days. Once the eggs hatch, both parents are responsible for feeding the young. The little birds leave the next 12 to 13 days after hatching. If conditions allow, sometimes a new nest is built and a second brood is raised.

Visit us this spring to hear—and see—the wood thrushes.