SY Males-The Enemy Within

copyright 2009
copyright 2009

When we talk about the dangers and hardships that purple martins face, we usually talk about about the usual suspects. Hawks, Owls, Starlings and Sparrows usually top the list with raccoons and snakes thrown in for good measure. But we often forget to mention the ugly truth about SubAdult (SY) purple martin males. Having survived their first round trip migration, the SY males are full of hormones and bravado and can sometimes make themselves the most unwelcome of guests.

I recently mentioned about the attack I witnessed in Gourd “C” on the Nestcam.  About a week and a half ago I was witness to a  SY male viciously beating on the 5 nestlings in that gourd. The SY was set on making trouble. Several times the SY female “mother” caught the trouble making SY male outside and gave him a good lashing. While she was gone, however, he would return and seemed intent on plucking the poor babies in the nest. Thank goodness for them they were about 23 days old and well feathered and substantial enough to take what he was doling out, but still it made me wince and I thought of the carnage that could have resulted if these babies were younger. This scene is not often witnessed but is actually quite common.

Often times when the younger SY males arrive they find either all the nest sites taken or all the females taken. Some of these trouble making bullies are simply out to break up a happy family with the hopes of convincing the female to re-nest and try again. If there are eggs in the nest they have been known to damage the eggs and experienced it myself this year in a previous blog entry, read about that attack HERE. That attack resulted in no damaged eggs but the male did become entrapped with the resident male inside which could have resulted in both of their deaths as well as the eggs. If there are hatchlings the SY males have been known to kill them.

What is the purpose of all this violence? Well, according to a fellow PMCA forumite and a well known and active martin landlord, Steve Kroenke, there are several reasons why. Read the article HERE. Can anything be done to stop this behavior? The only suggestion that I have heard that is feasible is to keep some housing closed, perhaps another house or gourd rack that is kept closed until the influx of SY’s take place. Even though this technique means that you will be hanging up a “No Vacancy” sign to many ASY purple martins, it can assure that the later arriving SY’s have a place to stake a claim to and thus defuse some of the aggressive behavior. Will this eliminate the problem? From reports it does have a noticeable result. Also important to note as this will not be a suitable technique for colonies that are not full. If there is available housing and you are noticing this aggression then just about all you can do is pray.

©2009 S.Halpin /

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