Each spring, the forests of New
Hampshire come alive with the arrival of migratory birds. Many
migrate from wintering areas in the tropics to take advantage
of the abundant insects and the long summer days of northern
areas, which are beneficial when raising young. This annual
spring migration to northern regions is a pattern that has repeated
itself since the last Ice Age, but it is one that has led to
considerable conservation concern in recent years.
Migratory birds have been declining
in abundance across North America, and researchers are scrambling
to figure out why. Is it because of changes on the breeding
grounds? Or changes where the birds winter? Or along their migratory
pathways? Is it habitat loss, changing weather patterns, or
some other factor? One of the ways to get at those questions
is to understand what factors in the environment influence how
well migratory birds survive and how many young they produce.
Male Black-throated Blue Warbler
(photo by B. Griffith).
At the Hubbard Brook
Experimental Forest in central New Hampshire, researchers have
been studying birds since 1969 and have particularly detailed
information about the breeding biology of a species called the
Black-throated Blue Warbler. Here, we will explore what has
been learned over the course of long-term research on this migratory
bird, asking questions like:
- How do you study
- What factors influence
the breeding success of warblers?
- How might changes
in climate impact this species?