Friday, April 19, 2013

April 17, 2013: Erv's Field Notes #56

Small flock of Blue-winged Teal on south lake. 4/16/13 (Erv Klaas)

Ada Hayden Heritage Park, Tuesday, April 16, 2013. Partly cloudy, east wind, temperature 44 degrees F.

I parked at Calhoun Park on the southeast side and walked along the south shore. A large flock of American Coots were hanging out around the lake outlet. A little further to the west I could see a large group of ducks huddled close together. As I got closer I could see they were mostly Shovellers. The Shoveller is a dabbling duck that has a large spatulate bill with serrations along the edge adapted for straining out micro-crustaceans such as copepods and daphnia from the water. I estimated there were a few hundred Shovellers in several “clumps” all along the shoreline. They reminded me of a group of vultures and ravens feeding on a mammal carcass. But these birds were swimming vigorously in place with their heads underwater. The groups consisted of both males and females and individuals were flying in from other parts of the lake to join the fun. Every few minutes the tightly packed clumps would “dissolve” for a minute or so and then reform. It was quite a sight. I have read about this kind of behavior in the Shoveller on their northern breeding ground but this is the first time I have seen it. Check out for photos.

A few individuals of other species were also present and seemed to be attracted to the “feeding frenzy.” I identified Bufflehead, Lesser Scaup, Blue-winged Teal, Eared Grebe and American Coot. Even a pair of Canada Geese showed some interest although these grazers are ill-equipped to feed on microscopic aquatic animals. As I continued my observations two Ospreys flew over and I saw a Common Loon far out in the middle of the lake. As I was leaving, the flock of coots on the eastern shore started leaving the water on foot, climbing over the riprap and up the bank to graze on the grass along the bike path.

If you have been to the park in the last month you may have noticed that a grove of trees on the north side have been cut down. The trees that were removed were Siberian Elm, an introduced species that is considered invasive in the park. Seeds from the older trees caused an infestation of a dense stand of seedlings in a nearby old field. The seeds have spread far and wide in the park and over time, we hope to eliminate them from the park. City crews have mowed this area a couple of times but they have re-sprouted. Friends of Ada Hayden Heritage Park have purchased 700 seedlings for a wildlife planting in this area. We hope the planting will take place on Wednesday afternoon, April 24. A Forestry class under the direction Dr. Richard Hall will be in charge of the planting. If you are willing and able, come on out. They may need some help.

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