Trilling stud lifts songbird population

If the loggerhead shrike ever leaves the endangered species list, major kudos must go to Trampas, the king stud of the songbird community on Navy-owned San Clemente Island.

Hatched in captivity in 2001, at the nadir of the shrike’s census, Trampas flew to freedom and began his life’s work: repopulating the shrike subspecies that is found only on the island.

In eight breeding seasons, Trampas has sired 62 chicks. From those chicks have come 93 grandchicks, 61 great-grandchicks and 25 great-great-grandchicks.

Where once the population was barely a dozen, now there are 80 breeding pairs in the wild and an additional 63 individual birds in captivity as part of a breeding program run by the San Diego Zoo.

Trampas is the program’s star graduate. Once released, he opted not to fly to one of the island’s deep ravines like many other shrikes, but rather to live and do his open-air wooing near the zoo’s research facility on the eastern edge of San Clemente Island, the southernmost of California’s Channel Islands.

“He gives you a front-row seat to shrike mating behavior,” said Jaelean Carrero, a research coordinator for the zoo’s shrike effort.

Other mating pairs -- some wild, some captive -- have been good breeders, but none with the brio and proficiency of Trampas and his longtime mate, known as Mrs. Trampas.

This year’s mating season, however, had a dash of drama. First, a younger male tried to come between Trampas and Mrs. Trampas. For days the two males strutted their stuff, awaiting her choice.

“It was quite a soap opera,” Carrero said.

Finally, Mrs. Trampas decided to stick with Trampas. Then she suffered a broken wing, possibly caused by an attack from a nest-raiding raven.

Alarmed that her demise could harm the 2-decade-old effort to revive the subspecies, researchers airlifted Mrs. Trampas to the veterinary hospital at the San Diego Zoo.

Alas, she could not be saved. Back on the island, Trampas found a new mate but no chicks came of their coupling.

With help from Trampas and his progeny, the military, the zoo, and the U.S. Fish and Wildlife Service may soon begin the lengthy, science-laden process of deciding whether the shrike can be upgraded from endangered to threatened.

At a cost of $20 million, the Navy has been trying since the early 1990s to revive the loggerhead shrike, often called the most endangered songbird in North America.

It has been a slow process. The track record of captive-bred birds surviving in the wild is mixed, making Trampas even more exceptional. No other captive-bred shrike has lived as long after being released.

Trampas’ island home is situated some 60 miles from northern San Diego County. The island’s southern end is used as an aerial and ship-to-shore bombardment range; at the other end, Navy SEALs from Coronado and Marines from Camp Pendleton practice amphibious assaults on the rocky, wave-washed shoreline.

As the shrike population has increased, the military has been allowed greater use of the bombardment area, even if it means some shrikes nesting there might be killed -- a process that wildlife authorities call an “incidental taking.”

Since 9/11, training has increased on the island, which is 24 miles long and up to 4 miles wide. A $20-million “combat town” was built for exercises simulating the kind of house-to-house fighting that Marines encountered in Fallouja, Iraq, in 2004.

More than 300 military personnel live on the island, along with several researchers from the zoo, five endangered or threatened animal species and six endangered or threatened plant species.

There are programs for other species. Colorado State University, for example, has a Navy contract to study the fox population. But the shrike has been the most public, a kind of test case to see if military training and endangered species can coexist.

In the zoo’s official stud book, Trampas is known as SB424.

His nickname was given to him by a zoo researcher in honor of a childhood pal from Oklahoma.

Although better known for his wooing technique, Trampas also knows how to beg a spare worm, cricket or lizard part that the researchers would otherwise feed to the captive shrikes.

“He does this pitiful quivering thing,” said Susan Farabaugh, conservation program manager for the San Diego Zoo’s Institute for Conservation Research. “He knows his audience.”

Beyond his reproductive prowess, zoo researchers have marveled at how his chicks have also become good breeders, with their chicks having a good survival record.

His progeny have their own group name.

“The Trampines are out there,” Farabaugh said.

--

tony.perry@latimes.com