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