Birds

Sometimes of late years I find myself thinking the most beautiful sight in the world might be the birds taking over New York after the last man has run away to the hills. I will never live to see it, of course, but I know just how it will sound because I’ve lived up high and I know the sort of watch birds keep on us. I’ve listened to sparrows tapping tentatively on the outside of air conditioners when they thought no one was listening, and I know how other birds test the vibrations that come up to them through the television aerials. ‘Is he gone?’ they ask, and the vibrations come up from below, ‘Not yet, not yet.’

Loren Eiseley

Its either going to be the birds or the insects that *make* it. Most people are betting on the insects.
However, its safe to say the polar bears dont have a shot.