Did You Know?
Why do birds migrate?

Bird migration is a wonder of nature, one that is still not fully understood. Migration is often viewed as the seasonal movement of birds during spring and fall to avoid harsh weather. The traditional view of migration is of birds flying south for the winter, however migration most likely evolved as a way for birds moving north to exploit resources, such as insects and nesting locations, that are seasonally abundant and avoid times and places where resources are scarce. Most birds are well equipped to handle cold temperatures (feathers are one of natures best insulators). Escaping the cold is a factor, but when there is no food birds must migrate.

Migration is complex. The mechanisms initiating migration vary across species and are not completely understood. Migration can be triggered by several factors, including: changes in day length, changes in temperatures, changes in food supplies, genetic predisposition, or some combination of some or all of these factors. Sometimes populations within the same species follow different migratory patterns. In addition, not all birds migrate long distances between continents, some species migrate across a few states and some simply migrate from higher elevations to lower elevations in the same mountain range.

For bird watchers the fall migration season is a fun and challenging time simply because the birds can be quite difficult to identify. The males no longer have their brilliant breeding plumage and have instead molted into a less distinguishable, less colorful fall plumage. Many males can be nearly indistinguishable from females in the fall. In addition, it can be quite difficult to tell one species from another as is the case with wood warblers in fall plumage (pictured below).

Yellow-rumped Warbler in Fall Plumage
Female Yellow-rumped Warbler in fall plumage
Blackpoll Warbler in Fall Plumage
Blackpoll Warbler in fall plumage