The Anhinga is an odd looking bird. Appearing superficially like the more common Double-crested Cormorant, the Anhinga can be differentiated by its needle like beak and its broad, fan-shaped tail.
These birds are rarely seen in the Dallas/Fort Worth area. I have only ever found them at Lemmon Lake in the Great Trinity Forest, and at the UT Southwestern Medical Center heron rookery as in this case.
There are several Anhingas at the UTSWMC rookery this year but is hard to be certain how many. They seek out perches in the interior of the park where they are hard to see from the edge of the woods. Fortunately, they also seem prefer the tree tops, which allows them to be viewed occasionally from the top of the adjacent parking garage.
They also spend a great deal of time flying over the rookery, where they can be seen soaring in high speed circles. Their unique configuration makes them unmistakable when observed from the ground.