Climbing the learning curve of short-tailed albatross recovery

Endangered Species Bulletin, Spring, 2009 by Judy Jacobs

How do you establish a new seabird colony? That was the question facing the Short-Tailed Albatross Recovery Team when it convened in 2005. Although the short-tailed albatross (Phoebastria albatrus), or STAL, was listed in 1970 as endangered, it was initially considered a foreign species. It was not officially protected in the United States until 2000, when the listing was corrected to protect the bird's habitat in this country. So, despite the species' long tenure as a listed species, recovery planning never really got underway until the new millennium. The fact that the STAL is international in range--nesting in Japan and foraging extensively in the waters off Alaska--presents interesting challenges in recovery planning.

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The short-tailed albatross is the largest, and was once the most numerous, of the three albatross species inhabiting the North Pacific Ocean. This species is further distinguished from the other two species, the Laysan (Phoebastria immutabilis) and black-footed (Phoebastria nigripes) albatrosses, by its disproportionately large, blue-tipped, "bubblegumpink" bill and the golden neck mantle of adults.

Once nesting extensively on islands throughout the western North Pacific, the short-tailed albatross neared extinction around the turn of the 20th century, a victim of the feather trade. Like the dodo in the Indian Ocean, the short-tailed albatross was unaccustomed to land predators and had no protective behaviors that worked against human hunters. (The Japanese name for the species, aho-dori, literally means "stupid bird."). Between 1885 and 1903, an estimated five million short-tailed albatrosses were taken from Torishima, a major breeding colony.

An interesting feature of the species' life history may have saved it from extinction. Young albatrosses remain at sea for 5 to 7 years before returning to nest and raise young. When a few surviving birds appeared at Torishima in the 1940s, they received vigorous protection. Today, the island's breeding colony has grown to more than 2,000 birds, and both the albatross and Torishima are designated as national monuments in Japan.

But the colony at Torishima is not without problems. The island is an active volcano that last erupted in 2002. Fortunately, that event occurred in August, when all the albatrosses had left for the year. Japanese scientists predict that the volcano is due for a major eruption, and next time the albatross might not be so lucky. To make matters worse, the birds nest on a steeply sloped and eroding alluvial outwash, where eggs and nests can be easily washed or blown away during monsoons and winter storms.

The only other place where short-tailed albatrosses are known to nest is an island in the Senkaku/Dioatsu group southwest of Torishima. Because Japan, China, and Taiwan dispute the ownership of these islands, they are very difficult to access. This colony was last visited by Dr. Hiroshi Hasegawa in 2001. Dr. Hasegawa, the species' patron and benefactor, has visited the Torishima colony almost every year since 1981 and written a great deal about these birds.

So, how could we set recovery goals for a species that nests on only two islands, one that is an active volcano and one that cannot be monitored? The team concluded that recovery would require establishing one or more additional short-tailed albatross breeding colonies.

Starting a new STAL colony is not unprecedented. Our colleagues at the Yamashina Institute for Ornithology in Tokyo have, over the past 10 years, successfully attracted breeding STAL to a more stable spot on the northwest side of Torishima using life-like decoys and recorded sounds from the main colony. Although safer from erosion, this second colony is still on an active volcanic island. The recovery criteria set by the team required colony establishment on a safe, protected island.

But how could this be done? Moving adults wouldn't work. These birds, which can easily negotiate trans-Pacific flights, would certainly return to their original breeding island. Moving eggs presents many other problems, such as the potential for breakage, incubation difficulties, concerns about chicks imprinting on humans, and providing proper nutrition for very young chicks. (Albatross parents feed them regurgitated stomach oil, which may contain enzymes, antibodies, or trace amounts of other ingredients essential for proper chick development.) Translocating older chicks seemed like the most feasible option.

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All we know about the post-fledging behavior of translocated albatross chicks comes from a single source: the innovative experiments of Harvey Fisher, who worked with Laysan albatrosses on Midway Atoll during the 1960s. Fisher found that nearly-fledged (about 4-month-old) Laysan chicks that were moved from their hatch site on Midway to Kure Atoll or Lisianski Island returned to Midway to breed five to six years later. However, when he reciprocally exchanged much younger (4- to 6- week-old) chicks between parent birds on Eastern and Sand Islands within Midway Atoll, most returned as breeders to the island that they had fledged from, rather than where they hatched. Thus, our working hypothesis is that albatross chicks geographically imprint on their future breeding location some time between one month of age and fledging (at about 4 months of age).