Tag Archives: Herring Gull

Kleptoparasitism – Stealing Does a Bird Good

Herring Gull with Red-breasted Mergansers

Waiting. Herring Gull with Red-breasted Mergansers. (click to see the larger version)

You may have noticed Herring Gulls hanging around groups of Red-breasted Mergansers at Montrose. The gulls are there for a good reason, at least for them – to steal fish the mergansers have caught. When a merganser dives and then surfaces with a fish, the Herring Gulls race in and try to snatch it. Sometimes it works and sometimes it doesn’t, but the gulls must succeed enough to justify the effort. This thieving behavior is called kleptoparasitism and is a common practice where mergansers and Herring Gulls occur together. It’s easier for the gulls to let the mergs do the hard work of finding food and try to steal it then to catch the fish themselves. No one ever said nature was fair or just.