Wednesday, July 15, 2015

Polygyny

When I am out in the field I see so many things that I think would be good to share with you all, and when I get home I often can't figure out what to write about! So many little dramas and interesting behaviors. If you remember, two years ago we had a male who had two families on two nests a few miles apart, each on different sides of the Mississippi River. We have seen cases of polygyny before and usually one nest gets more attention and the other nest fails. But much to our surprise, that male pulled it off that year, successfully raising SIX chicks on two nests! Plus providing for two females. The following year he decided to stick with one nest and allowed another male to take over the other territory. That male remained on that other nest this year as well. BUT the polygynous male did it again this year. But this time he set up his "mistress", for lack of a better word, on the old nestpole within a few hundred feet of his nest on a transmission tower! These females could see each other. This year, however, the outcome was different. One nest failed, from lack of attention from the male. He was not providing food or sharing the incubation duties on the second nest and tho that female gave it a gallant try, she could not pull it off. Her eggs never hatched and she abandoned the nest attempt. It's interesting to see this particular males tendency towards polygyny. One might expect to see this behavior when there are not enough males around, but our population has grown dramatically and I see many single males out and about, looking for females and territories. It's always fun to observe the aberrations to what might be considered normal behavior. Perhaps the growth of the population just provides more opportunities for these behaviors. 

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