Bird species outnumber mammals by more than 2 to 1. I think we have a inbuilt sampling bias for mammals, because that's what we interact with more. There are no

Bird species outnumber mammals by more than 2 to 1. I think we have a inbuilt sampling bias for mammals, because that's what we interact with more. There are no living birds that prey on humans or eye-catchingly big ones, that may also explain the bias. Dinosaurs have never left or went extinct. It is more like all big animals(birds and sea dwelling creatures included) died during last mass extinction. A lot of small ones (less than 35lb, by one estimate) did make through.