Do hummingbirds migrate in flocks?

Hummingbirds migrate individually. When a late October straggler in the East is a Ruby-throated Hummingbird, it’s usually an immature bird from further north whose mother got a late start with that nest. Ruby-throated Hummingbirds are strongly migratory, but their bodies need a high level of fat to fly long distances. As people bring in their feeders in fall and frosts kill nectar-bearing flowers, those hummingbirds remaining have to go long distances between feeders, so yours may remain for a week or two before its body is replenished enough to continue. Hummingbirds are surprisingly hardy as long as they can get enough food each day, and they need extra calories during cold spells.

Oddly, many of the hummingbirds that turn up at Eastern feeders late in the season aren’t Ruby-throated Hummingbirds at all! For some reason, more and more Rufous Hummingbirds from the West are heading southeast instead of directly south to Mexico. Believe it or not, one of these turned up in my northern Minnesota backyard on November 17, 2004, and remained for over two weeks! And sometimes tropical hummingbirds such as Green Violetear turn up at feeders in the U.S., often in fall. So look carefully at yours just in case, and keep the food fresh. When it’s cold, it’s not a bad idea to up the concentration of sugar to 1/3 cup per cup of water to give it more calories, which they burn while shivering.

Tragically, some of these stragglers do end up dying, but your feeder really isn’t keeping your hummingbird from migrating. Rather, your feeder is giving it its best chance to restore its body to continue on.