Quick identification
Caspian tern (Hydroprogne caspia)
The world's largest tern, with broad wings, a heavy red bill and a dark cap that becomes streaked outside breeding season.
Season and local range: Regular year-round visitor, often more visible in cool months.
Habitat and island setting
Open bay, Gulf surf, passes, jetties and broad sandbar roosts.
Where to look
Scan from Isla Blanca, the causeway and bayside viewpoints for a tern that looks almost gull-sized. Birds may move as tides, wind, fronts, water levels and activity at the site change.
What the bird is doing
Its deep call and powerful flight stand out. As with every tern roost, approach only until you can watch without making heads rise or wings open.
Watching birds
Use binoculars or a camera zoom, stay on public paths and leave feeding, resting and nesting birds enough room to continue normal behavior. If a bird stops feeding, stands alert, calls repeatedly or moves away because of you, increase the distance. Check access information in the South Padre Island birding guide before making a special trip.