Hummingbird migration

[olcop]

I've always been curious about their migration, given that they have such a high metabolism how do they sustain themselves on the trip to South America? Moreover, how does such a small lightweight bird with such a rapid wingbeat fight the air currents? I've read that they "hitch hike" a ride on another large bird, such as a goose, but I've also heard that they migrate in large flocks of hummers, so I don't know which is correct, or, if either is correct.
What is the life span of a hummer, since their diet consists of mostly sugar and they spend all their waking hours moving about at top speed, it seems they would be prime candidates for early heart attack.
olcop

 

[coach]

Not to mention type 2 diabetes

 

[mishtub]

Here is some info you might find interesting:
http://www.hummingbirds.net/migration.html
More info:
http://www.worldofhummingbirds.com/migration.php

 

[pisgah]

What is the life span of a hummer, since their diet consists of mostly sugar and they spend all their waking hours moving about at top speed, it seems they would be prime candidates for early heart attack.
olcop

They also eat approximately 200+ tiny insects (like fruit flies) per day.