Over at Delta Lake, I ran into Mary who had just seen a Common Tern fly by. I had never seen this coastal species in the county before. A few minutes of waiting produced my 379th Hidalgo County species.
This is a bit of a tough ID when the bird is in flight as a moltling Forster's Tern can have a similar head pattern with a black nape. The dark outer rectrices and dark edged primaries say Common Tern. The next photo barely shows the dark carpal bar which is easy to see on a resting bird.