[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Altitude effects on hummingbird flight?

----- Original Message ----- From: "don ohmes" <d_ohmes@yahoo.com>
To: <dinosaur@usc.edu>
Sent: Thursday, December 21, 2006 9:55 AM
Subject: Altitude effects on hummingbird flight?

Hummingbirds are the largest observed species using hovering, a
size-constrained locomotion;

No, a number of other, much larger birds use hovering -- but they do it by means of a different technique, full momentum reversal (the flutter stroke). You will see hawks doing it regularly while hunting, and they are for the most part, larger than hummingbirds.

if some "un-related" group of similar size
evolved hovering, it seems to me that a high degree of convergence
would be expected.

There is another small african species that regularly hovers (I forget its name), but it doesn't fly backwards and doesn't suppinate the wing to the extent that hummingbirds do. Other, larger species hover by means of a very different technique -- no convergence.

In either case, I wonder what could have knocked
them out? Given that hummers occur in Alaska, it astonishes me that
they never got a foothold in Asia. Anybody know got a clue?

Nope, not a clue. I'd expect 'em to spread as well. They are very good at what they do.