Hermit Thrush

The song of the Hermit Thrush is one of the signature sounds of the spring woods across much of New Hampshire. It is one of the first songbirds to arrive, sometimes as early as late March, and certainly well before the leaves are out on deciduous trees. It occurs in all forest types from the seacoast to high elevations but is relatively uncommon as a breeder at the extremes, as well as in large urban areas. Hermit Thrushes are also one of the last migratory forest birds to leave, with some lingering into November in the south and increasing numbers remaining through the winter.

Hermit Thrushes spend much of their time on the ground, where during the nesting season they feed primarily on insects, snails, and occasionally small vertebrates such as salamanders. These are all obtained by either searching through leaf litter or probing into the ground. While foraging they will also sometimes leave the ground and hover briefly to take prey from the undersides of leaves or twigs. In fall and winter they incorporate a higher percentage of fruit into their diets, especially farther north, although studies have shown that they prefer animal to plant items at all times. Given the difficulty of finding insects in New Hampshire during the winters, the thrushes that stay here gravitate to patches of fruiting shrubs such as winterberry, usually within forested habitats.

Although Hermit Thrush is categorized as “stable” in New Hampshire, this designation masks some interesting shorter-term trends. The decline we see starting in the late 1990s appears in most states and regions in eastern North America, and its timing matches shifts from increasing to decreasing trends in several other forest birds (but not all of them). At present there is no clear explanation for these trends, and perhaps no one investigating them closely, so one can only speculate on what’s causing them. Options include disease, increasing migration hazards, climate change, habitat loss, and pesticides, but none of these explain why declines aren’t seen in other co-occurring birds, and more detailed research is clearly needed.