May has finally arrived! The overwintering patience of the many a “cabin fever” shut-in has paid off with an April full of bluebells, birdfoot-violets and hoary puccoon flowers. Now May is upon us and new flowers will soon greet those who trek the hills, hollows and floodplains of central Illinois. Spring is a season for floristic wonder. But May, especially, is also a time for one of the great animal mysteries known to man — bird migration.
Beginning in April, birds that overwinter in the Tropical Rainforest return to their northern nesting ground. Soon our natural areas will not only be ablaze with bloom, they will be alive with song. The Hermit Thrush, one of the first neo-tropical migrants has already started its journey and is enjoying the habitat offered by our wooded parks. This relative of the robin will soon leave us and journey further north to its boreal realm.
Bird migration is one of the greatest mysteries known to man. There seems to be no singular reason that migration has developed. It appears that there are different advantages of migration in different groups of birds. Even the time of the day that birds will migrate differs among species. For instance, herons, hawks, eagles, falcons, crows, hummingbirds, swifts and swallows all migrate during the day, while all passerine birds (except crows, swallows and a few others) migrate during the night.
Reasons for this might be that nighttime travel offers birds protection from daytime predators. Traveling at night might also allow songbirds to feed during the day when insect populations are more active due to the warmth of sunlight.
After certain physiological and behavioral developments have taken place in birds as a result of changes in the length of daylight, the bird is ready for migration. It appears that weather patterns play a role in the triggering of migration in both the spring and the fall. In springtime, migration usually takes place at the onset of warm fronts. As each low-pressure system passes (with mild temperatures and southerly winds), bird movement proceeds in full force. When cold fronts arrive, bird movement will stop and not continue until high-pressure systems have passed. Migration in the fall operates somewhat in an opposite manner.
Migration is actually something that can be seen with high resolution Doppler radar. Flocks of birds can also be observed at night. An old method employed by bird biologists (that still works today) is to observe the full moon in the night sky and count the waves of birds that cross the pale disk of the moon.
How many different birds can be found in the habitat offered by our Peoria Parks? On May 9, 2015, 143 species of birds were seen in Peoria County on the Spring Bird Count conducted by The Peoria Audubon Society. There’s many a bird to view in these woods, prairies and rivers!
If you want to learn more about our fine feathered friends, join in a bird hike or program. Forest Park Nature Center is offering both beginner and advanced birding classes in May. They also have several drop-in bird hikes throughout the year. In-depth Birding Tours along the Illinois River take place in late summer. Call Forest Park Nature Center 309-686-3360 and ask about the programs being offered. You can also pick up a copy of the new Peoria Park District Summer Playbook at any PPD facility, or view it online at http://www.peoriaparks.org/playbook/