American robin in flight (photo from Wikimedia Commons)

2 October 2025

The mix of migrating songbirds is changing this month, but migration is still in full swing. When the weather is right, songbirds take off an hour+ after dusk and may fly eight hours before they stop before dawn. Last week was especially intense for migration, as described by BirdCasts’s Kyle Horton for NBC 7 San Diego.

All of these nighttime migrants are flapping. How much energy does this use up?

Back in 2005 a biotelemetry study of Swainson’s thrushes measured heartbeat and wingbeats in flight and concluded that they flapped about 11 beats per second on sustained migration. In eight hours that means about 311,000 wingbeats — a lot of flapping for a small bird — and some of them flap even more, such as the ruby-crowned kinglets who’ve just started to pass through our area.

Ruby-crowned kinglet in flight (photo from Wikimedia Commons)

Amazingly, flapping is more efficient than soaring. Find out why in this vintage article from 2017.