As we proceed through Wisconsin’s four seasons each year, you may appreciate the sight of colorful songbirds in springtime and notice the distinctive V-shape formation of Canada Geese as they fly south in the fall. These species are referred to as “migratory birds”, or populations of birds that travel from one place to another at regular times during the year.
Why do birds migrate?
Birds migrate in search of resources needed for their survival. Migratory birds primarily pursue sources of food or nesting locations to raise their young. In Wisconsin, we see an influx of bird species in springtime as warm weather returns and insect populations increase. As temperatures begin to drop in the fall, food supply dwindles and the birds fly south.
How do birds migrate?
Scientists believe there are many factors that trigger the migration of bird populations. Birds respond to changes in their environment such as day length, temperature, and availability of food resources. Additionally many birds go through hormonal changes with the arrival of new seasons. These hormonal shifts may affect your caged birds at home, you may recognize restless behavior in spring and fall. This restlessness around migratory periods is referred to as zugunruhe.
It isn’t fully understood how birds have developed such impressive navigation skills, but there are several factors that guide them. Birds can use directional information using the sun, stars, and even earth’s magnetic field. Landmarks, position of the setting sun, and even smell plays a role for various species.
How do scientists study migratory birds?
Several methods have been developed to track and study migratory birds including banding, satellite tracking, and by attaching geolocators to individuals. At Snapshot Wisconsin, trail cameras are now being added to the list of tools! Using preliminary data gathered from Zooniverse, the below slideshow shows the detections of Sandhill Cranes on Snapshot Wisconsin cameras throughout the year. The study of migration can be immensely beneficial for conservation efforts by pinpointing wintering and nesting locations to monitor potentially threatened or endangered populations.