World's Oldest Bonin Petrel!

Bonin petrels are nocturnal seabirds that live only in the Northwestern Hawaiian Islands, and a couple small islands off the shores of Japan.  They are a little bigger than your hand, and feed at night alone or in pairs, near the surface of the water.  Because they are nocturnal and breed in burrows (or artificial nest boxes), they are difficult to monitor.  They can only live on islands that have no predators like rats, mice, cats and dogs.

The largest BOPE populations exist or existed on Lisianski, Midway, and Laysan Islands.  Those populations were heavily impacted by the recent tsunami, as hundreds (or perhaps thousands) of active nests were inundated.  Unfortunately, the petrels are not monitored at those locations. At Tern Island, however, we have a very small but steady population of Bonin Petrels that we study at night throughout the breeding season.  Our small population appears to be holding steady or increasing -- but we only have a 20-30 breeding pairs on Tern, versus 10s of thousands that are/were on Lisianski, Midway and Laysan.  We do have an excellent opportunity to study the birds at Tern Island, however.

We just got the official word, and three petrels that Dan Rapp and Sarah Youngren observed this winter all break the existing record for oldest (longest lived) Bonin Petrel in the world!  The previous record was a 22 1/2 year old BOPE.  Dan and Sarah found two birds that were breeding adults in 1981, and one bird born in 1981, as identified by their metal bird bands.  The two older birds are probably at least 35 years of age, although we don't really know for sure, other than they were breeding adults 30 years ago.  Not only did these birds break the record for longevity, they have been breeding now for 30 years.  Pretty amazing!

Sarah Youngren with the last of the season's Bonin Petrel chicks from Tern Island before fledging, June 2011.