Monday, March 26, 2012

Mar 25, 2012: Erv's Field Notes #28

Blue-fronted Dancer Male--Hayden Park, Ames, Iowa (Erv Klaas)

Sunday, March 25, 2012. 1:00 to 2:30 pm. Beautiful sunny day. Temp. 76 degrees. Gentle south breeze.

The weather this weekend has been fantastic. On Saturday, the park was visited by hundreds of runners who participated in a benefit "Run for Malawi". You can see photos at Kevin Kane's blogspot:

Saturday was also a "Day of Insects" at Reiman Gardens. Wolf Oesterreich and I presented our five years of data on Dragonflies and Damselflies at AHHP. Our presentation was one of 15 presentations at the fourth annual meeting of this group that attracted more than 100 people. I showed a slide of a damselfly, a Blue-fronted Dancer, that had captured an insect. One of the entomologists identified it as a member of the insect Order Mecoptera, and I was later able to identify it to species as a "hanging fly" on a web site called Bug Guide. This web site was developed by entomologists at Iowa State U. and has become the "go to" site all over the world for users to identify their insects from photos. The hanging fly has very long front legs with a hook at the end which it uses to hang from branches of vegetation. The long legs and distinctive head were clearly visible on my photo.

Wolf reported that he saw the first dragonflies of the season last Wednesday and Thursday, March 21 and 22, at the park. These dragonflies were Common Green Darners and on Thursday he observed them ovipositing (laying eggs). Entomologists believe this species migrates to the Gulf Coast for the winter and darners that appear this early in the spring are probably early migrants from the south rather than emergents from the ponds.

On Sunday afternoon, Janet and I walked up the upland trail to Jensen's Pond. While Janet sat in the swing at Rotary Overlook, I walked around the pond. One of the first birds I saw was an Eastern Phoebe. It caused me to recall that 50 years ago, almost to the day, I began a four-year field study of this species near Lawrence, Kansas that became my doctoral dissertation in Ornithology. The thesis was titled "Breeding Ecology of the Eastern Phoebe and its relationships with the Brown-headed Cowbird." The Eastern Phoebe is a member of the flycatcher family of birds and usually builds its nest made of mud and grasses on buildings are other structures. It likes protection from the elements so its nest is always under an overhanging eave of a building. In eastern Kansas it uses concrete culverts or road bridges as nesting sites. I once found a phoebe nest tucked under a rocky outcrop but natural sites in Kansas were scarce as they are in Iowa. The phoebe is a frequent host of the Brown-headed Cowbird that is an obligate social parasite. The cowbird lays its eggs in the nests of a large variety of species and the host does all of the work of raising the cowbird young. Such behavior has evolved independently several times among avian families, for example, old-world cuckoos.

This morning (Monday), a phoebe appeared suddenly in my back yard, the first time I have seen it in the yard in 37 years. It must be some kind of omen because yesterday, I saw a Brown-headed Cowbird in the yard.

Erv Klaas

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