Blue Jay

The Blue Jay’s bright colors, loud voice, and in-your-face attitude make it of the most familiar backyard birds in the eastern United States. Because they are so visible, it is also easier to notice their absence, and backyard birders are quick to get concerned when their jays seem to disappear. This is usually in the winter, but not every winter, and the reason is a simple but little-known fact: Blue Jays migrate. There will always be a few that stay put all year, but others may move as far south as Georgia during their September/October migration period. The number that leave is tied to the availability of acorns and other nuts in the fall. When these are abundant more jays remain in New Hampshire for the winter. Those that leave return in April and early May, and you can sometimes see large loose flocks moving north during the day along our major river valleys.

The association of Blue Jays and oaks is so strong that they are believed to be one of most important means of seed dispersal for these trees (squirrels can’t fly!). One calculation even suggests that the rate at which oaks moved north after the last ice age can be explained via the average distance a Blue Jay travels to cache food. Any acorn stored for later use and then forgotten is a potential oak tree.

Although most of their diet is nuts and seeds, jays consume insects and other animal prey during the breeding season when seeds are less available. Included here are the eggs and nestlings of other birds, which as a result often act aggressively towards jays during the spring and summer. Despite their boisterous demeanor, Blue Jays are usually subordinate to smaller or less imposing species (e.g., cardinals, Mourning Doves) at winter feeders. They still dominate the smallest birds such as chickadees, earning them the ire of feeder watchers for being bullies.