Birders at Black Lake Preserve for the Eastern Sierra Land Trust’s World Migratory Bird Celebration in 2025. Photo: Gena Wood.

Join Eastern Sierra Bird Alliance and the Eastern Sierra Land Trust for Spring Big Day.

May 9 is an important day for birds and for birders around the world. Each year, the second Saturday in May is recognized as World Migratory Bird Day for U.S. and Canada, where we are experiencing peak spring migration. A worldwide bird count is held on that day, called Global Big Day. (Fall migrations are celebrated on the second Saturday of October.)

You can contribute to Global Big Day by using eBird to record the birds you see on May 9. Want to go birding with a group? Join our COSA walk or go birding in the Black Lake Preserve.

Your eBird data helps researchers create more accurate and up-to-date maps of bird migration. And thanks to innovations in bird tracking, you can see those migrations in amazing detail:

Birdcast shows the flights of millions of birds as they are detected by radar. Find out how many birds flew over your county or community last night, or look at migration forecasts.

The Bird Migration Explorer shows the locations of actual tracked birds, as well as patterns based on studies—many of which use eBird data!

Enjoy spring migration and the birds it brings to the Eastern Sierra.