Dane County Humane Society’s Wildlife Center rehabilitates dozens of sick or injured migratory birds each year.
On any given night in the past month, it was estimated that anywhere from a few hundred thousand up to tens of millions of birds were in flight over the state of Wisconsin! Like all migratory bird species, they were flying southward to seek more abundant food sources as cold temperatures start to set in during the winter months.
It may be surprising to hear that fall migration actually begins in the summer months and extends all the way into early winter, depending on the individual species. Peak migration is seen from August through October, and as of early September this year, an estimated 623 million birds crossed over the state on their journey to their wintering grounds! There are websites dedicated to monitoring bird migration, which is how they get these estimates.
While most birds take to the skies at night, some species are diurnal migrants, meaning that they travel during the day. A well-known example of these daytime migrants are geese, but other species include pelicans, heron, swifts, hummingbirds, and birds of prey that can maneuver in warm air thermals.
Fall migration may conjure images of far-flung flights, but not all birds are actually long-distance migrants. Migration encompasses a range of behaviors with some species staying within a small region or traveling a few hundred miles. Some even stay year-round and are considered semi-partial migrants like our local Northern cardinals, black-capped chickadees, American crows, and red-tailed hawks.
To illustrate a great example of this difference, DCHS’s Wildlife Center recently released two migratory visitors: a Swainson’s thrush and a palm warbler. After receiving clean bills of health and ensuring they had plenty of healthy fat stores for their long trips, each bird was fitted with an individual federal identification band and set out to continue their travels.
The Swainson’s thrush is a long-distance migrant, traveling from the far northern regions of North America down into a long stretch across the length of South America. The palm warbler, on the other hand, is a medium-distance migrant that stays within the southern United States and Caribbean region during the winter months.
There’s still plenty of time to get outside and see some visiting birds through the end of the fall migration! You can also keep up to date with migration estimates to see what species may be flying through your area by visiting The Cornell Lab BirdCast.
Cameron Cook is a Wildlife Assistant and Social Media Volunteer.