Captive-bred Florida Grasshopper Sparrows make conservation history

5/13/2016 | 0

An adult Florida Grasshopper Sparrow tends to captive-bred chicks in the nest.

Florida Grasshopper Sparrows, courtesy of Rare Species Conservatory Foundation (RSCF).

Conservation history was made May 9, when the first captive-bred Florida Grasshopper Sparrow chicks hatched at the Rare Species Conservatory Foundation (RSCF) in Loxahatchee, Florida — a major breakthrough for one of North America’s most endangered birds.

The Florida Grasshopper Sparrow (Ammodramus savannarum floridanus) is a nonmigratory subspecies of widespread, familiar Grasshopper Sparrow. The subspecies is found only in the dry prairies of south-central Florida. Because of habitat loss, restricted distribution, and population decline, it was listed in July 1986 as endangered.

“This bird is teetering on the brink of extinction; there are probably less than 150 left,” said Larry Williams, state ecological services supervisor for the U.S. Fish and Wildlife Service. “We’re working with our partners — including the Florida Fish and Wildlife Conservation Commission — to save it. This is a huge milestone in those ongoing efforts.”

A conservation milestone

Five nestlings from two different clutches and two independent juvenile birds were collected from the wild and taken to RCSF in 2015. It was the first time the species had ever been brought into captivity.

“We had two situations where a monitored nest was predicted to fail (one from flooding and one from the loss of the brooding female),” explained a lead biologist on the recovery effort. Both clutches were collected and brought to RSCF, where they were successfully hand-reared to independence.

“Because of concern of starting a captive-breeding program with strictly naive birds, and because we believed that hand-reared birds would benefit from a ‘tutor’ bird, we also brought in two independent parent-reared, juvenile birds.”

Pairs were established in April 2016, when the birds began exhibiting breeding behaviors. The first nest attempt by one of the females was unsuccessful, but a second brooding female began hatching a clutch of four eggs on May 9. As of May 11, the female appears to be properly caring for and feeding her four nestlings.

According to USFWS, if things continue to go well, the chicks will leave the nest and start trying to fly about nine days after they hatched. They should be fully independent about three weeks after they hatched.

Williams acknowledges that USFWS and its partners implemented captive breeding because this is an “extremely urgent” situation.

“This captive-breeding program might buy us time to unravel the compounding factors causing the sparrows to decline so rapidly. We seem to have good habitat that’s not being used. That makes us think the population levels may have dropped so low that they’ve lost the power to recover,” he said. “Below certain population thresholds, there can be combinations of predation, disease, genetic inbreeding, and gaps in social behaviors that make it difficult for a species to rebound.”

Despite the welcome news about the captive-breeding efforts, preliminary numbers for the 2016 season are looking very bleak. According to USFWS, biologists are expecting a steep decline from the previous two years’ low, but somewhat stable, counts.

Listen to the song of Florida Grasshopper Sparrow.

Read the recovery plan for Florida Grasshopper Sparrow (PDF).

The Rare Species Conservatory Foundation.

 

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