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Field Notes No. 17 (Dec. 30, 2011)

Friday, December 30, 2011. No wind, temperature 48 degrees F.

What a beautiful afternoon for a walk. Most of the ice on the lakes had melted again and the water was smooth as glass. Most of the geese were in the west arm of the south lake, sleeping on the little ice left in that end of the lake. It looked like a good opportunity to get a count. Looking down on the birds from the elevated path made it easier. Looking through binoculars, I first counted 10 birds one by one. I did this for the first 100 birds. That gave me a good idea of what 100 birds looked like as a segment of the flock. Then I estimated the number of groups of 100 for a total of about 1100 geese. People often ask me how do biologists count birds in a large flocks. That's how its done, although conditions vary and estimates can be good or bad depending on the view, whether the birds are clumped close together or spread apart. The same procedure is used to count birds in flight. It is easi! er to count them when they are flying in long skeins. Ducks are more difficult because they don't fly in formations like geese do.

A little later in my walk, I counted 160 geese on the partially frozen north lake, including the three Snow Geese that I have been reporting in previous notes. I saw a female Bufflehead swimming near the ice in the south lake and a hundred or so Mallards were in the middle of the lake with some mixed in with the geese on the ice. I did not try to count Cackling Geese separately today but I would estimate they comprised about 10 percent of the flock. Last Tuesday, when most of the geese were swimming in open water, there was a lot of bathing activity. Bathing involves a lot of splashing, wing flapping, and even somersaulting in the water. Geese get dirty when they are feeding in the crop fields and so cleaning their feathers is important for insulation and for flight.

While I was writing this, Wolf Oesterreich sent me th! is note:

Sunday, New Year's Day, January 1, 2012. Sunny, strong NW wind.
Like a stubborn, crazy fool, I went out and rode (his bike) in this wind! Most of the geese (Cackling & Canada) were gone by the time I went to the Park. A raft of about 100 Mallards was all that remained. During the second lap, the female Bufflehead flew over the bridge and landed in the south lake's west bay. While on the Upland Trail, I did see the juvenile white Snow Goose with Canada Geese on Pond E. It was too far to see clearly and too windy to set up the scope to determine the presence of the other two Snow Geese. The most astounding sight was that of an Eastern Garter Snake, "sunning" on the trail (southwest corner of the south lake, where Pond N [south wetland complex] dumps into the south lake). I have never seen a snake in Winter in Iowa.

Best wishes for the New Year,

And Erv