(Not) Flying South for the Winter

When the weather turns to spring and flowers blossom many U.S. bird lovers look for the hummingbirds to return to local nectar feeders or flower patches. For a lucky few in particular parts of the U.S.—especially in the West Coast, South, and Southwest—hummingbirds hang around all year long. That’s been the pattern for years, but things seem to be changing. Birders are documenting more hummingbirds that have opted to overwinter in the U.S. For example, during the 115^th Christmas Bird Count, birders found 312 Ruby-throated Hummingbirds in expected locales like southern Florida, but they also spotted the birds in North Carolina, South Carolina, Georgia, Louisiana and Texas. The question is: Why? Did these winter birds forget to migrate?

Scientists are hoping to answer this question, in part by looking at data from citizen science programs like Hummingbirds at Home, to see if these shifts mirror the shifts in climate and flower-blooming times. There is ample evidence that this shift is occurring. The 1974 book “Louisiana Birds” by George H. Lowery, Jr., lists five documented hummingbird species in Louisiana. Today, there are 13. Of those species, only the Ruby-throated Hummingbird regularly breeds in Louisiana and the eastern US. The others merely pass through or winter in Louisiana.

In recent years more people in Louisiana have been managing their yards and gardens with hummingbird-friendly plants. Do these hummingbird friendly places attract the birds to come to Louisiana, or conversely have the increasing number of wintering hummingbirds resulted in the setting out of an invitation by interested people? Providing a nectar feeder will not delay a hummingbird’s migration, but will help them with a food source during their journey. They will migrate once the day length indicates it is time to go south. But there is still a lot to learn about hummingbird migration patterns and why they might be in places we don’t expect in winter.

The Ruby-throated story is even more complicated than it seems on the surface. Individual birds do not stay in Louisiana; instead, overwintering birds migrate as far north as Canada to breed, while those that show up in the spring actually overwinter in Central America. The Louisiana Winter Hummingbird Project, which focuses on banding wintering hummingbirds, documented that one Ruby-throated Hummingbird banded there during the winter was found a few months later in Manitoba during the breeding season. This project was started to learn more about the unexpected hummingbird species showing up out of season in Louisiana.

The more we look at these kinds of data and watch hummingbirds, the more questions we have. By collecting data about where the hummingbirds are in winter and what they are feeding on during their return to breeding areas, citizen scientists provide the valuable information to help us answer some of these questions. Help us learn about the hummingbirds near you when they return home, and tell us what nectar sources they are visiting by joining at www.hummingbirdsathome.org.