Single Day Birding Trip in the Rio Grande Valley

Here's a 24-hour birding itinerary for South Texas to maximize species based on eBird information:

Day 1:

Morning:

Start early in the morning by heading to the Bentsen-Rio Grande Valley State Park, which is known for its incredible diversity of bird species. Look out for species such as the Green Jay, Plain Chachalaca, and Golden-fronted Woodpecker.
After a few hours of birding, head to the Edinburg Scenic Wetlands, which is home to several species of waterfowl, herons, and egrets. Keep an eye out for the Black-bellied Whistling Duck, Fulvous Whistling Duck, and the Green Heron.

Afternoon:

Next, head to the Estero Llano Grande State Park, which has a variety of birding habitats such as thorn forest, wetlands, and ponds. You might spot the Altamira Oriole, White-tailed Kite, and the Olive Sparrow.
For lunch, stop by the Weslaco City Park and grab a bite to eat while enjoying the scenic views. Look out for the Red-billed Pigeon and the Groove-billed Ani.

Evening:

End your day by visiting the Santa Ana National Wildlife Refuge, which is known for its rare and endangered species such as the Hook-billed Kite, Aplomado Falcon, and the Altamira Oriole.
Finish your day with dinner at one of the many delicious restaurants in McAllen or Edinburg.

With this itinerary, you'll be able to maximize your birding experience in South Texas and potentially spot a variety of bird species. Happy birding!