According to a new study, the birds -- which are also known for their high-footed shimmy of a mating ritual -- have been dancing less and less. Published this week in the journal Avian Conservation and Ecology, the study details the booby's decline over the last several decades.
The birds once walked the beaches of the famed Pacific islands west of Ecuador in great numbers. In the 1960s, the population sat around 20,000. Today, it's less than 6,400. Between 2011 and 2013, only a few boobies were observed mating, and birds with juvenile plumage were nowhere to be seen.
Scientists say the decline has coincided with a decrease in sardines cruising the shallow waters of the islands made famous by Charles Darwin. Previous studies have shown that blue-footed boobies increase their sardine consumption during mating season. Still, researchers aren't sure what exactly is responsible for the booby's decline.
"Understanding the population dynamics and distribution of sardines in Galápagos is a logical follow-up project -- essentially nothing is known at present," study author Dave Anderson, a professor of biology at Wake Forest University in Winston-Salem, North Carolina, told National Geographic.
Sea lion numbers -- another species that feeds almost exclusively on small fish -- have also been on the downturn.
"From what we do know, it seems at least possible that a variety of predators are being affected by this change in baitfish availability," he said.