Thursday, April 24, 2014

Apr 20, 2014: Erv's Field Notes #65

Variegated meadowhawk in flight.  I also saw several pairs ovipositing
by tapping but did not get a picture of this behavior. 4/20/14 (Erv Klaas)

Sunday, April 20, 2014.
Sunny, gentle south breeze, temperature 72 degrees F.

I parked in the SW parking lot off Harrison Road and walked the upland trail on the west side. I noticed that Country Landscapes has put small white marker flags along the trail. The flags are marked on one side as Hawth BB or Bur 10. I assume this means Hawthorn or Bur Oak. The Parks and Recreation Department intends to plant 150 trees this year in city parks in celebration of the city’s 150th birthday. The area on both sides of the trail is reconstructed prairie. Planting trees along this prairie trail may seem incongruous with prairie management that tries to control woody species. At least, Hawthorn and Bur Oak are resistant to fire and it is not unusual to find these two species in prairie savanna areas.

4/20/14 (Erv Klaas)

I took a side trail over to the two ponds nestled in the willows where I saw a large concentration of ducks a couple of weeks ago. The first pond in the complex is now full of water with a trickle of water flowing over the concrete weir into the second pond. I flushed eight Blue-winged Teal, a pair of Mallards and about 20 American Coots from the first pond as I walked in. I took my seat on the concrete weir abutment between the ponds and took out my camera. I could see Canada Geese, American Coots, Blue-winged and Green Winged Teals, Northern Shovellers, and Mallards in the second pool.

Several Common Green Darners and Variegated Meadowhawks were patrolling the shoreline. and as they passed close by I was able to get a few photos of these dragonflies in flight. I also observed both species in tandem laying eggs in the water. The biological term for this is ovipositing. The method is different in the two species. The male of both species maintain their grasp of the female with claspers on the end of its tail. All dragonflies and damselflies in the Order Odonata have these claspers that are specially adapted to grip the female behind the head during mating and egg laying. The claspers are uniquely shaped in each species and are used in species identification if you have the insect in your hand. With modern field guides, most species can now be identified with binoculars. The Common Green Darner pair lands on dead vegetation in the water and the female dips her tail an inch or two into the water. So as not to place all her eggs in one place, the pair shifts their position every minute or so. The Variegated Meadowhawk pair skims over the surface of the water and the female taps the end of her abdomen in the water as they fly along. I have read that the female may lay as many as 50 eggs with each tap. Both of these species are known to be migratory, and are the earliest dragonflies to be seen in the spring.

This painted turtle was about 4 inches in diameter. Evidence of reproduction and winter survival. 4/20/14 (Erv Klaas)

While I was taking pictures of the dragonflies, a small Painted Turtle, about 4 inches in diameter, found a perch on a large rock not far from me. This young turtle indicates that reproduction is occurring in the pond and that this individual survived the extreme winter temperatures we had this year.
Last Friday, Jim Pease and I walked around the south lake and observed a flock of 17 Horned Grebes. The Horned Grebe has become a regular migrant through the park but this was the largest number I have seen at one time. The flock stayed together for the whole time we were at the park and showed off their swimming skills by moving all the way from the east side of the lake to the west side at about the same pace that we were walking.

Erv Klaas

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