COLUMN: Fall migration is in full flight

Michele Olson
Jones County Naturalist

   Fall is upon us! As the landscape changes colors before our eyes, temperatures begin to drop, and each day grows a little shorter, many of our aerial neighbors have begun their southward migration. Have you noticed this annual phenomenon?

   You may have had robins nesting in your yard this summer but now they are gone. Many robin flocks begin forming shortly after nesting season. As food sources begin to dwindle and autumn arrives, flocks head south following the availability of earthworms and insects they prefer to eat. Any robins sticking it out in Iowa during the winter will resort to surviving on berry/fruit producing shrubs and trees in urban landscapes and scattered forest habitats.

   If you have hummingbird feeders, you may have noticed highs and lows of hummingbird activity. Mid-September can be very busy with resident and migrating hummingbirds vying for precious sugar water as the migration begins in full force. Hummingbirds follow the blooming flowers on their way to Central America and Mexico and will disappear from Iowa as native blooming flowers begin to wane.

   Interesting flocks of mixed species of warblers and other songbirds will begin appearing, subtly darting and bouncing in the branches as they glean bugs and fruit from area trees.  You might notice their varied colors, bobbing tails, or interesting migration calls as they hide in plain sight. Feeding during the day, these little migrants often make their way south, many heading all the way to areas in South America, during the cover of darkness.

   Red-winged blackbirds, done nesting, are now in large feeding flocks gaining vital fat to survive migration and overwinter in southern states and Central America. They may join flocks of starlings, grackles, cow birds, and other blackbirds as they travel, roost, and feed.

   Swallows, like the cliff swallow, migrate in large flocks of up to 200 or more. Lined up on wires during the day, these graceful, beautiful small aerial acrobats are hard to miss. Swooping and darting above fields and ponds, these little birds must hunt daily for insects to sustain their migration flight. Heading to South America, they wander ever southward following available insects and warm temperatures.

   Broad-winged hawks migrate through Iowa in high flying swirling flocks referred to as “kettles.” These small hawks with banded tails leave North American forests and migrate to northern areas of South America each fall. Watch the autumn skies when the north winds blow. These hawks might also be in loose mixed flocks with turkey vultures and other southbound migrating raptors. If you see one, look for others.

   And, of course, waterfowl will soon be flocking together and following strong cold fronts as they too head south for the winter season. When strong cold fronts pass by, watch local ponds, lakes, and rivers to catch a glimpse of these travelers. Muskrat Slough, west of Olin, and Central Park Lake are two good birding locations to observe migrating waterfowl.

   If you’re interested in learning more about migrating birds, visit ,, and

   You can help migrating birds by limiting light pollution at night, planting native trees, shrubs, and flowers, and preserving wetlands, prairies, and forested habitats.




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