SAN ANTONIO — Researchers in San Antonio are getting ready to welcome what's expected to be one of the biggest groups of Monarchs to come through the Alamo City since 2008.

Each year, the monarchs travel through San Antonio on their journey from Canada to Mexico for the winter.

Experts say is a special sight because the entire migration is in danger of disappearing and monarchs themselves are being considered for endangerment status this year.

Changes in their environments including the decline in the number of milkweed plants that the butterflies feed on are part of the problem.

"We have to have 1.4 billion stems, billion with a 'B', stems of milkweed in the ground to save the monarch migration over the next ten years," Laurie Brown with the San Antonio Zoo said.

It will take a lot of new plants, but saving the beautiful creatures, Brown says, can be done.

"There's a lot we can do to save them. Like by planting plants, building butterfly gardens in your backyard," she said.

Most butterflies will travel through San Antonio from mid-October to through mid-November. This month's rain has helped flowers flourish so researchers are hopeful those flowers will attract more butterflies.

When those butterflies arrive, people like Brown will help tag some of them.

"We put a tiny sticker on the outside of the wing of the bottom wing of the Monarch butterfly. It's so tiny it doesn't harm them. But it has a certain number on it so we can  catalogue where that butterfly was tagged and if it made it to Mexico," she said.

A few butterflies made the journey early. Scientists in Mexico located the first arrivals on September first.