Monday, July 7, 2014

July 6, 2014: Erv's Field Notes #68

This female Eastern Pondhawk was found in the north grassy area at Jensen Pond.  The male is blue.
Total Length = 38-44mm; Hindwing Length = 30-33mm; Flight Season = May - Oct. 6/8/14 (Wolf. Oesterreich)

Erv's Field Notes #6

Sunday, July 6, 2014. Calm, Cloudy, Temperature 80 degrees F.

My friend Rick Dietz offered to give me a ride in his canoe around the perimeter of the lake on Saturday morning but it rained, so we did it this morning. The water level in the lake is high due to recent rains and the flooded Skunk River. The city shut the outlet gate to prevent the Skunk River from back flowing into the lake. A week ago there was several inches of water over the fishing dock. But the gate has been open, and today the fishing dock is dry. Water still covers the riprap along the shoreline.

The three pairs of Canada Geese that successfully hatched young this year were all together on the west end of the north lake. The young are nearly full grown. One pair had four young and the other two pairs each had two young. Later on the south lake we saw a family of Mallard ducks swimming in the flooded vegetation along shore. I was unable to get a count.

The water in the lake is relatively clear but a significant amount of filamentous algae is beginning to develop in the south lake. It has not yet formed a solid mat but is made up of softball-sized floating clumps. This is a sure sign that phosphorus is increasing in the lake.
We say many large patches of Sago Pondweed growing just off shore in both the north and south lake. This submergent vegetation can grow in clear water up to 10 feet in depth. It is a perennial that produces tubers in the sediment and long stems leading to floating oval-shaped leaves at the surface. A few patches were beginning to develop flowering stems which protrude several inches above the water. These fruiting bodies are favorite perching places for damselflies. The tubers in the sediment store carbohydrates and are preferred food for diving birds such as the Canvasback duck.

We saw swirls and waves created by large fish swimming near the canoe but could not identify them. They could have been carp, large-mouthed bass or striped bass. As we passed the outlet on the south lake we could hear water rushing through the spillway.

Erv Klaas

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