Park on the north peninsula by the "lake" (really just a wider portion of the Comal River). Begin walking by the gazebo and pier and look outward for the best waterfowl viewing, especially closer to winter. Continue walking parallel to the river as far down as you can before turning around and returning to the gazebo/pier. Birders often skip Panther Canyon, but it can offer some nice views of passerines. 

If you're birding the main park by the lake, try to be done by around 9-9:30 AM because it can get crowded with locals, especially on days with nicer weather. Panther Canyon is never near as crowded.

Waterfowl including cormorants, ducks, geese, coots, grebes, etc.

Landa Park is a popular park located in New Braunfels, TX. It includes multiple walking trails alongside the Comal River as well as large hardwood trees good for passerines. It also contains the Panther Canyon trail through a forested area with a seasonal creek.

Panther Canyon and all lake-adjacent trails.