Have you noticed geese flying overhead recently? If you haven’t, you will soon. That is because the spring migration is on. Although some have the impression that birds fly non-stop to their winter or summer destination, there is considerable variation in the migration patterns of our feathered friends such as migration distance, time of arrival, or flight time.
Through bird banding, population surveys, harvest surveys, and other techniques, biologists have identified four waterfowl migration corridors or flyways in North America. North Dakota lies within the Central Flyway which is roughly the Great Plains. Westward lies the Pacific Flyway. Eastward is the Mississippi Flyway which as the name implies runs along the Mississippi River and finally the Atlantic Flyway. National Wildlife Refuges serve to support a wide array of wildlife, and are particularly important in that they serve to provide needed stopover sites for migrating waterfowl.
Some other birds, such as robins are known to have northern populations and also southern populations. Both populations migrate southward during the fall migration, with northern population largely replacing the southern population. Come spring, the process is reversed as the northern population returns northward. In the case of red-winged blackbirds, migratory populations from the north will join permanent residents in the south during the winter months, then return northward during the spring migration.
And of course, a quick look at the range maps of birds in most bird guides will show that the winter ranges of the birds differ considerably, with some migrating a relatively short distance while others amazing distances. House wrens for example have spent their winters in the southern states and Mexico while bobolinks are coming back from some southeastern states, the Caribbean, or even South America.
If you are patiently or impatiently waiting for your special avian friends to return, there are a few websites linked below that monitor the migration of several birds (e.g., hummingbirds, robins) and some other species, as well as plant phenology.
