Physical 

Caspian terns have a similar appearance to gull species but can be differentiated by the thin shape of their wings as well as the black “cap” on their head. This species is 18.5-21 inches (47-54 cm) long with a 50 inch (127 cm) wingspan. Their long red beak is also key to their identification and can also have a slightly darkened coloration on the end of it.

Image by ksblack99 on Flickr

Habitat

Caspian terns are coastal species, found in habitats such as salt marshes, beaches, and barrier islands.

Feeding 

Due to their coastal habitat type, Caspian terns typically feed on only fish and occasionally invertebrates when needed.