Galápagos: Home to the boobies
IS THERE ANY BIRD more entrancing than a booby? The sideways glance, the slightly brazen swagger, the twinkle in their eyes that suggests they find you as amusing as you find them…which seems reasonable given their name.
‘Booby’ is said to come from the Spanish term bobo, which means ‘fool’ or ‘clown’. They may have been thus named because boobies are ungainly on land, as seabirds often are.
They were also thought foolish for their fearlessness of humans – a problem that drove many species toward extinction as they made easy picking for passing mariners. Sailors at sea found boobies landing aboard ships easy to catch and a ready meal.
There are seven booby species worldwide. The three found in the Galápagos archipelago – the red-footed, Nazca and blue-footed – pointedly demonstrate that not all boobies are created equal. Red-footed boobies, the only one of the Galápagos trio that nests in trees, are friendly but rather aloof. They eye you off from a distance, but don’t engage. If you invited them over, they’d probably politely refuse.
Nazcas are the snooty ones; the kind of guest who’d need an outdoor sun lounge to sit on, proper cutlery and the correct wine glass. Blue-foots, however, would be gathered round the barbecue, paper cups in hand, teasing each other in raucous chorus: the first to poke fun at themselves and the last to leave. This, perhaps, explains our fondness for them.
The Galápagos’ most endearing bird is known for its strutting-and-blue-foot-waving mating ritual. And its spectacular plunge-diving for food, which can see them spear into the water at speeds approaching 100km/h.
Breeding concerns for the blue-footed booby
David ‘Dave’ Anderson, Professor of Biology at Wake Forest University, in North Carolina, USA, has a soft spot for blue-foots, and right now he’s concerned about their long-term welfare. Dave’s study of the reproductive life history of Nazcas on Española Island has been running for three decades; he’s banded 17,000 individuals over that period.
“It’s a very tractable system,” Dave says of working in the Galápagos. “The birds have no fear of humans and they handle attention easily.”
Over the years, he’s studied them in parallel with Nazcas on Española. “And then in the mid-1990s, we noticed that they’d stopped breeding, and we hardly see blue-foots on Española now,” he says. “That was really the first indication that a problem might exist.”
Other long-term Galápagos researchers remarked that they’d noticed the same trend in other parts of the archipelago. “So there was a weak case, an anecdotal one, but we decided to go ahead with the [population] study,” Dave says.
In 2011 – with support from the Galápagos Conservancy, Galápagos Conservation Trust and Swiss Association of Friends of the Galápagos – Dave began a blue-foot population study. He’s now in the final stages of analysing data, and is careful to say that the conclusions aren’t yet clear. “But it does appear that the population is half or less its size than in the 1960s,” he says.
There are still about 10,000 birds around the archpielago, but Dave says the indications are there’s been no effective blue-foot breeding for the past two years, and he suspects that they’re pickier eaters than we thought. It seems that sardines – or the lack of them – is part of the cause.
“The Española blue-foots had an almost exclusive diet of sardines, but sardines disappeared from their diet in the 1990s,” he says. “Throughout the islands, less than half the blue-foots’ diet is sardines now. They’re finding food enough for self-maintenance, but not enough to breed.”
Dave’s not entirely certain why sardines are favoured by blue-foots (“sardines contain more lipids, which might be it”), nor does he know the reason for the decline in sardine availability. “But my attitude is it’s not a human cause,” he says, adding that the local artisanal fisheries are too small to account for the low availability.
The other Galápagos boobies don’t seem to be suffering the same decline. The Nazca population has been stable, at several times the size of the blue-foot’s, throughout the period that Dave’s studied them, and Red-foots are thought to number 100,000 or more. But the 10,000 remaining blue-foots are the attention-getters, and worth so much more than the source of poor puns on Galápagos tourist T-shirts.
They’re universal: one of them seems to pop up or dive down wherever a Galápagos visitor goes. As they hit the water they look similar to tuxedoed Exocet missiles, but on land, as they saunter up to you, tip their head to one side and tap their feet to catch your eye, there’s no greater pleasure than to sit and enjoy their company. May the next few breeding cycles bring them a whole lot of food for the barbecue.
The full story can be found in Australian Geographic #114.