Wildlife experts are saying that a recent cold front has brought cooler weather and thousands of flying visitors to Rio Grande Valley skies.
Valley residents have reported thousands of butterflies from Roma to Brownsville.
One viewer sent in a video of thousands of butterflies in the Cameron County town of Rio Hondo.
Action 4 News spoke to the Gladys Porter Zoo about the butterflies.
Zoo officials said most of the butterflies are the American Snout, a brown and orange butterfly often seen in the days after a rain.
Pat Burchfield with the Gladys Porter Zoo reported that the butterflies are also swarming because a thorny shrub known as the coma plant is in bloom.
Action 4 News also spoke with Marianna Trevio-Wright with the National Butterfly Center in Mission.
Trevio-Wright said the recent cold that arrived in the Valley also brought many butterflies with it.
The cold front arrived just ahead of their annual migrating season, which for many species of butterflies runs through mid-December.
In addition to the American Snout, Trevio-Wright said Valley residents are likely to see sulfur butterflies, which are yellow in color, and the Queen Butterfly, which is known as the false monarch because it has markings similar to the popular Monarch Butterfly.