The Gunnison sage-grouse, a bird with an unusual “bubble pop” mating call and display, could be America’s rarest bird, according to avian experts.

The bird was only discovered 13 years ago, and yet it’s already nearly a goner. Today, fewer than 5,000 of these birds remain in the wild, and they are rapidly dwindling.

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“In my view, the Gunnison sage-grouse is the most biologically endangered bird species in all of continental North America,” Cornell Lab of Ornithology director John Fitzpatrick said in a statement sent to the U.S. Fish and Wildlife Service.

The chicken-sized bird has an amazingly unusual mating ritual. To court females, the males strut about while wagging their spiky tails and making a popping-like noise as they inflate yellow air sacs from their white chests.

Fitzpatrick and others are paying attention to this bird now, as it’s a candidate for listing as endangered under the Endangered Species Act. The Gunnison sage-grouse only lives in eastern Utah and Colorado.

“The Gunnison sage-grouse is now in imminent danger of a series of local population collapses, which — when they occur — will result in extinction of the species,” Fitzpatrick explained.

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Efforts by public agencies and private landowners to help stabilize the bird’s populations through private land easements, conservation plans and community education have not halted its decline, says Fitzpatrick.

Despite the bird’s precarious status, getting a species endangered classification can be a long, laborious process.

For example the Dakota skipper butterfly, on the candidate’s list since 1975, is now extinct in Indiana and Iowa. The Eastern Massasauga rattlesnake has been a candidate since 1982. And the Kittlitz’s murrelet, a small bird, has been on the candidate’s list for nearly 20 years.

“It is now urgent that the Gunnison sage-grouse be listed as an endangered species, and that a recovery team be assembled to fast-track recommended steps for halting the decline and imminent extinction of this remarkable bird,” said Fitzpatrick.

(Image: Gunnison Sage-Grouse by Noppadol Paothong)