Friday, April 22, 2016

2016 Purple Martin Season 2

Performed a nest check today and found the first eggs of the season.  Eight in total from three different nests.  There are seven other nests that were empty and about four partial nests.  Looks like the season is getting off to a good start.  I'm also seeing a total of three SY (second year) or "subadult" males hanging around.  This is unusual since in the past I might see one maybe two at my colony, but not this many right at the beginning of the season.  They usually show up later.

In the past I've had lone SY bachelor males actually build a nest along with the adults in the colony.  Naturally there were no eggs since it had no mate.  This can be harmless and it can also be a problem.  At times SY males will go into the nests of adult martins and destroy eggs and kill nestlings.  It's all about competition.

As I've written before- Infanticide by definition is basically the killing of young by adults. This behavior occurs in other bird species as well such as House Wrens, Tree Swallows, Barn Swallows, Cliff Swallows, English Sparrows and European Starlings. It is believed that unmated SY male martins perform this act because of limited nesting sites, mates, and food, which then is intensified by the urge to mate. By removing and/or killing the young or destroying eggs it causes the mated pair to “divorce” so to speak due to reproductive failure. This gives the SY male the chance to take advantage of the situation and possibly mate with the now “free” female.  During the time that this has happened before there was only one subbie present.  Now I'm seeing three so this could make for an interesting season.  Stay tuned.

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