Origin of Birds

The Dino-bird link seems to be pretty strong. As I understand it the development of the digits is not yet confirmed, and is still in dispute.Mayr's argument regarding the teeth, on the other hand has not to the best of my knwoledge been refuted.But on the other hand, the evidence from the wrist structure seems rather stronger to my eye.This page may be a reasonable start for looking at the evidence from the other side of the story (read it for the positive arguments for the dino-bird link - it doesn;t really deal with the opposing arguments).Dinobuzz: Dinosaur-Bird Relationships

In fact there are several species of ducks that do swim underwater.The "sawbills" (mergansers and relatives) even have serrated bills for catching fish. Others include ruddy ducks, tufted duck (I think the North American equivalent is the ring-necked duck) and pochard.And there are plenty of other birds that dive for food as well, including cormorants and grebes (little grebes can be particularly annoying at diving just when you are trying to find them!).