About the Refuge
The most southern tip of Texas, where the Rio Grande meets the Gulf of Mexico, is considered one of the most biologically diverse regions in North America.
During migration, species from the Central and Mississippi flyway converge in the the lower four counties of Texas known locally as the Lower Rio Grande Valley (Valley). Where possible, migrating birds avoid flying too far east (over the Gulf Coast) or too far west (over the desert) and end up funneling through this region. In addition, many birds from South and Central America reach the northernmost point of their range on the Rio Grande with some species literally not migrating any farther north than the river.
In addition, the Valley is where four climates (temperate, desert, coastal and sub-tropical) converge. The 365 day growing season and rich soils of the Rio Grande delta have helped create a documented 1,200 plant species within the Valley. This plant diversity attracts and supports a diversity of wildlife, birds and butterflies that depend on the vegetation that can only be found here in the United States.
The habitat is the result of thousands of years of adaptations and changes on the landscape that have created species-specific relations found only in portions of the lower Rio Grande delta.
Since the 1930s, 95 percent of the native habitat found within the Valley has been cleared for agricultural or urban development. This development has relegated native plants and animals to remnant tracts, possibly compromising the genetic integrity of many species. Hoping to connect and protect these isolated tracts of habitat, the Lower Rio Grande Valley National Wildlife Refuge was established in 1979 with a management priority to protect biodiversity. As a wildlife corridor, the refuge follows the Rio Grande along the last 275 river miles, connecting isolated tracts of land managed by private landowners, non-profit organizations, the State of Texas, and two other National Wildlife Refuges, Laguna Atascosa and Santa Ana.