Bentsen–Rio Grande Valley State Park and Anzalduas County Park Professional Review and Guide
"The 588-acre state park as well as lands below Anzalduas County Park are part of the extensive Rio Grande Valley Wildlife Corridor, a multiagency project to protect tracts of native landscape between Falcon Dam and the mouth of the Rio Grande. Ten habitat types and more than 115 unique vertebrate species occur within this corridor. Bentsen is one of two key birding sites in the lower Rio Grande Valley (along with Santa Ana National Wildlife Refuge), but is preferred by campers and nighttime birders. Santa Ana is open only during the daylight hours. The state park is primarily a nature park, although fishing is available on Oxbow Lake.
Key birds: Least Grebe, Neotropic Cormorant, Anhinga, Fulvous and Black-bellied Whistling-Ducks, Masked Duck, Hook-billed Kite, White-tailed Kite, Harris’s and Gray Hawks, White-tailed Hawk, Plain Chachalaca, Red-billed Pigeon, White-tipped Dove, Groove-billed Ani, Pauraque, Buff-bellied Hummingbird, Ringed Kingfisher, Green Kingfisher, Golden-fronted Woodpecker, Northern Beardless-Tyrannulet, Great Kiskadee, Green Jay, Claycolored Robin (irregular), Long-billed Thrasher, Olive Sparrow, Pyrrhuloxia, Bronzed Cowbird, Altamira Oriole, and Audubon’s Oriole are present year-round. Roseate Spoonbill, Wood Stork, Purple Gallinule, Elf Owl, Brown-crested Flycatcher, Western Kingbird, Tropical Parula, Varied and Painted Buntings, and Dickcissel occur in summer."