Photo of Terns
Different species of terns are found throughout California, with the Caspian Tern most common in the San Francisco Bay Area. The Royal Terns pictured here are similar to Elegant Terns, and can be difficult to distinguish. Royal Terns have a thicker bill but similar shaggy crest. They do show up in the Bay Area, less commonly, and generally passing through on migration.
Terns are pelagic (sea) birds found worldwide. They range in size from 8 or 9 inches (Least Tern) to 21 inches (Caspian Tern). Elegant Terns are only slightly smaller at 17 inches.
Tern identifying characteristics -- as compared to gulls:
- Generally smaller and more slender than gulls
- Pointed wings
- Straight and pointed bills
- Most terns plunge head first into water to catch prey
- Quick movements and turns in flight, different from a gull's
Their diet is primarily fish, but they also eat aquatic invertebrates.