Birds of a feather use a bit of a tweak for a perfect beak

THE beak of a bird is a wonderful thing. I was thinking this the other day when I was doing some waterside bird-watching.

I watched, in succession, a kingfisher, a heron and a cormorant.

These three birds look very different and are not even remotely related to each other. But they all have similar beaks: a serious looking dagger-shaped object on the front of their faces. The reason, of course, is that they all catch fish and, by a process biologists call convergent evolution, they all ended up with the best design of beak for the job.