Mourning Warbler

Mourning Warblers are among the first species to colonize an area after a timber harvest, sometimes as early as one year later. They prefer habitats dominated by brambles, low shrubs, and seedlings and saplings of conifers, birches, and aspens. They are just as quick to leave these areas as young trees mature and are usually gone after only ten years. Birds like this are sometimes called “fugitive species” because they are constantly moving around the landscape in search of ephemeral patches of suitable habitat.

Like other early successional species, Mourning Warblers increase and decrease in response to availability of their preferred habitat. And because land-use practices vary across their range it is not unusual to see population trends vary as well. The general trend in northern New England has been one of increases through the 1980s followed by irregular declines and leveling off. A slight increase since 2015 may be the result of increased timber harvesting in parts of Maine and adjacent Canada.

In New Hampshire Mourning Warblers are most common north of the White Mountains, with densities declining through the mountains and south into the western highlands. They are one of the last species of warbler to arrive in spring (often into early June) and first to leave in fall (late July into August), so most summer records outside the core breeding range are likely migrants, especially in southeastern New Hampshire. Mourning Warblers spend the winter in Central America and northwest Columbia, where they retain their preference for thickets and second growth.