Public Release:  Lack of breeding threatens blue-footed boobies' survival

Wake Forest University

Blue-footed Boobies are on the decline in the Galápagos.


The drastic drop in population is probably due to an unexplained disappearance of sardines from the Boobies' diet, said Dave Anderson, a professor of biology at Wake Forest University and the study's principal investigator. This in turn has adult Boobies electing not to breed. Without breeding, old birds die and are not replaced but new young adults, and the population shrinks.

Where did all the Boobies go?

Scientists started noticing a strange trend at the Galápagos' 10 or so Blue-footed Booby breeding colonies in 1997. The colonies were simply empty.

"Until 1997, there were literally thousands of boobies' at these breeding sites and hundreds of nests full of hatching chicks," Anderson said. "Then suddenly, the Boobies just weren't there. There were a few cases where we found isolated breeding attempts but most of these didn't produce chicks."


"That was the start of the conversation," he said. "We started to ask ourselves, 'Is something weird going on with the Blue-foots?'"




Electing not to breed



This suggests the birds find their current, low sardine diet sufficient to live but insufficient to breed successfully. "We think the main factor behind the decline is a scarcity of food," Huyvaert said. "Whether that's natural or linked to anthropogenic change, we aren't sure."

So now the question is, where are the sardines, said Johannah Barry, president of the Galápagos Conservancy, which provided funding for the study. "Are they being overfished, are they leaving Galapagos waters due to climate change or other pressures?" she said. "If they are leaving what other fauna might be impacted?"

Anderson said further investigation is important now rather than later due to the fact that the Boobies' perennial lack of breeding for the better part of two decades means that young birds are not replacing old ones. The majority of their population in the Galápagos must be nearing elderly ages where raising offspring will become hard, if not impossible.

"We have a convenient explanation that isn't anthropogenic," Anderson said. "But if humans are in fact contributing to this decline we need to get to the bottom of it now rather than five years down the road when you have the equivalent of 75-year old humans trying to breed."

