Common merganser engages in cooperative fishing behaviour
Male common merganser. A female hooded merganser is in the background. Munson Pond. I was at Munson Pond yesterday taking photos of birds. The ice had just recently come off the surface and the entire water body was clear of it. What was there in its stead were birds; hundreds of them. The largest collection was Canada geese, but I was amazed at how many hooded mergansers there were too. And then I saw them; large and colourful - male common mergansers. In all, there were maybe a dozen common mergansers, both males and females. The common variety were much larger than the hooded ones. However, they didn't mind hanging out together, and they exhibited a most interesting behaviour. They all dove at once. Called cooperative fishing, it is a behaviour that increases the chances of any one individual catching a fish. One bird on its own has to either be very lucky on its dive or has to chase down a fish fleeing for its life. M...