Expert: Roger Lederer - 4/26/2009

Question
QUESTION: We were very surprised when yesterday we saw two male ducks stomp a female
duck to death right next to the lake alongside our house.  Our neighbor ran out
and tried to stop them, but the males kept coming back.  Later that day the
female duck died. Why did they do this?

ANSWER: I can't give you an exact answer because I don't know the exact situation - the habitat, the species, whether these are wild or domestic ducks, how many ducks are around, where you are located, etc. But it is unlikely that two males just beat up a female just to beat her up. I suspect that they were just competing to mate with her and got too aggressive and injured her. I often receive questions about male ducks attacking females, especially pushing them underwater, when all they are doing is trying to mate.

---------- FOLLOW-UP ----------

QUESTION: We live in Liberty Township outside of Cincinnati, there is a small lake and these
are wild ducks.  I agree that it is unlikely, that they just stomped her to death for
no reason.  They were using their feet during the attack, and the males attacked
her together.  I've lived here for 5 years and have enjoyed the ducks so much and
this is the first time anyone in the neighborhood saw anything like this.  Is it too
late in the season for mating?  Could she have had some physical anomaly the
males identified and simply got rid of by attacking her?  I'm used to seeing
animals during their mating rituals, I watch alot of Discovery TV etc.  Not quite
used to seeing animals attack their own, especially ducks.  We have some geese
and a lone crane in our neighborhood.  Thank you for answering

Answer
There are too many possible variables in this situation.These may be wild ducks but they are apparently in a semi-domestic area - used to people, etc. So I can't give you an exact reason. I can tell you that this is not unusual - males do attack females from time to time. However, another possibility is that the "female" is really a male. After males breed, they take on the plumage of the female and look just like a female until they molt in the fall into their mating plumage. There's no way to tell what sex the bird in female plumage is this time of year unless you are an expert.