Much about the spring and fall migrations are cloaked in mystery, from how birds know when to leave to what helps them determine exactly where they’re going.
But there’s no question about one element of their twice-a-year extreme feats of travel: the moment the birds stop for breaks, they go to work eating seeds, beetles, worms, flies, moths, bees, lizards, caterpillars, fruit, nuts, nectar, fish, spiders, snakes, suet, mice, and sometimes other birds.
The migration is a feeding frenzy.

A Yellow-rumped Warbler wrestles with an inch worm.
Dining is a vital part of the day – and a fascinating element of the journeys that four to five billion birds are in the midst of about now across the U.S. They need to eat meals that for us would be pretty much impossible.
The hummingbird, for instance, has to consume its entire weight in nectar every day. For a normal sized human, that’s the equivalent of drinking 18 gallons of milk, according to the Audubon Society.
The Chickadee has to eat about a third of its weight in seeds, berries, insects and worms daily. For us, Audubon says, that would translate into eating 600 granola bars every day.