• Dale Bowman

Aaron Yetter flys: Teal on the move

The latest entry from Aaron Yetter, who does the storied waerfowl surveys for the Illinois Natural History Survey.

September 9th, 2015 – Aerial Waterfowl Inventory Blog

We had a major influx of teal into the Illinois and Mississippi rivers this week. The increase

was likely due to the weather system that passed through the prairies over Labor Day

weekend. This week’s teal total (62,265) along the Illinois River was 143% above the

10-yr average (25,603). Teal abundance along the Mississippi River nearly quadrupled

this week and were estimated at 20,455 birds. We are way ahead of normal for the second

week of September with duck numbers 125% above average for the Illinois and 258%

above average for the Mississippi River. I even saw a few gadwall, American wigeon, and

ruddy ducks on Wednesday’s flight. As nightly low temperatures in North Dakota dip into

the upper 30’s and low 40’s over the weekend, I am sure we will see even more migrating

ducks heading our way.

Ducks undergo multiple feather molts at various times of the year. Ducks even molt their

flight feathers after the breeding season which renders them flightless for a few weeks

during summer. During this flightless period, a duck’s feathers are very drab and brown

in color. In fact, a drake mallard loses that brilliant green head during summer and

resembles a female at this time of year. For this reason most of the birds during the

September flights appear as “brown ducks” from the airplane. To estimate species

abundance in September, I sometimes intentionally flush ducks from the water so I can

see their wings and identify them. This photo from Wednesday’s flight shows the wing

color and size differences in a few of the species I encounter. You should be able to find

blue-winged and American green-winged teal, mallards, northern pintail, northern shoveler,

and maybe even an American black duck in the picture. For more information about the

waterfowl survey, check out our webpage at

Good luck teal and Canada goose hunting and stay tuned for more updates next week…….

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