Rio Grande Valley bird watchers are wondering why they're spotting a lot of rare birds in the area. 

There are even some birds that live south of the Valley that are never seen. But lately, birders have been seeing more and more birds from Central America and Mexico coming this way.

The mystery of why the increase in rare bird sightings was brought up at the Winter Wildlife Expo at South Padre Island.

"There's plenty for them to eat. It's like a smorgasbord down here," New York native Jonathan Wood said.

Wood said the food variety helps and is what makes this region especially good for birding.

But this winter, birders have counted at least 10 different sightings of rare species.

Some of them have been spotted in the Valley for the first time in more than a decade, and some never spotted here before.

Naturalist and educator at the SPI Birding Nature Center Javier Gonzalez is one of those taking a guess as to the reasons behind this.

"Some say El Niño, climate change is also a factor, I think," Gonzalez said.

Whatever the cause, it's drawing people to the Valley this year.

Watch the video above for the full story.