ST. LOUIS COUNTY, Mo. - Say the word "butterfly," and the iconic orange and black of the monarch may immediately spring to mind. But they are becoming a rarer and rarer sight in nature.

"The number of butterflies that are overwintering in southern California and central Mexico are much, much lower. They are ninety to ninety-five percent lower than they were a couple of decades ago," Tad Yankoski, senior entomologist at the Sophia M. Sachs Butterfly House, said.

The drop in numbers has led the U.S. Fish and Wildlife Service to propose that monarch butterflies be listed as threatened under the Endangered Species Act.

"Which will offer them new authority to offer protections that weren't previously available," Yankoski said.

So, what has happened to these once plentiful insects? It all comes back to habitat loss.

"One hundred, 200 years ago, there were a lot more prairies across most of North America, including right here in Missouri. And they need flowers to feed on during their migration. They need milkweed to feed on and to lay their eggs on."

Monarch butterflies in the eastern United States and Canada migrate to Mexico to spend the winter. Monarchs west of the Rocky Mountains overwinter in southern California.

"They are facing so many complications along the way. Droughts, wildfire, loss of habitat due to farming, increased use of herbicides and pesticides, logging of their overwintering grounds," Yankoski said.

There have been direct climate change issues too. Monarchs rely on nectar from fall wildflowers to fuel their 2,000-mile migration.

"Because of climate change, some of those flowers are now blooming a couple weeks or even a month or two later than normal. So, they are no longer blooming when you fly south," Yankoski said.

But all hope is not lost. Recent conservation efforts, large and small, have slowed the drop in numbers.

"So, you absolutely can make a difference," Yankoski said.

Now is a great time to get your seeds going for your spring planting. And planting a pollinator-friendly garden in your own backyard is one of the best things you can do to help the Monarch butterfly.

"Plant native plants. Plant native milkweeds," Yankoski said. "Every little garden is an island in that ocean that can provide sanctuary for a butterfly on its journey."

The Butterfly House hosts a pollinator plant sale every spring where you can find multiple varieties of milkweed and wildflowers.

"We also have our Project Pollinator program, where we are putting gardens in local community centers and helping people with resources," Yankoski said.

While it sounds like bad news, should the monarchs officially get listed as "threatened," the odds are in their favor.

"Once a species is listed as protected under the Endangered Species Act, it historically has a 99% chance of recovering," Yankoski said.