The Continuing Analysis of Blue-footed Booby Populations

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Sula nebouxii, better known as the blue-footed booby, is one of the most recognizable birds that call the Galápagos Islands home. Fears that blue-footed boobypopulations were on the decline lead to a series of comprehensive studies with the goal of enumerating the remaining birds. Researchers connected with these studies also hoped to find out more about what caused the decline as well as offer advice about what could be done to save the birds.

Preliminary studies completed in 2012 confirmed that the population was indeed on the decline. Conservationists believed that there wasn't enough food to go around any longer. Clupeid fish like sardines are threatened, and reduced fish populations can't support the growth of stable flocks of predatory birds. The group of scientists that conducted this study concluded that the decline in blue-footed booby populations is part of a long-term trend influencing animals across the Galápagos Islands .

However, they also wrote that further studies were needed to conclude that the population dip couldn't be traced to normal fluctuations. New data suggests that the trend might have reversed itself slightly. A number of tourists had claimed that they saw hatchling boobies in 2017. Researchers were curious as to whether they could take a census of just how many young boobies hatched in the first half of that year.

Before they began their new study, these researchers took a look a paper compiled by three eminent biologists in May 2011. This paper made heavy use of data collecting during the first comprehensive population study of boobies. They noticed that many breeding sites once frequented by boobies had been essentially empty since 1997.

The biological research team went through four exhaustive searches of their own in 2011. Once they'd been through every major breeding colony they began a coastal survey that went across almost the entire archipelago throughout the next year. They were only able to find around 100 hatchling boobies, which indicated that few adult birds were mating. These scientists estimated that there were upwards of 8,000 adult birds left in 2011 compared to upwards of 30,000 birds in the 1970s.

It looked like the lack of food was keeping the boobies from breeding. Studies on Española demonstrated that boobies won't reproduce unless they have access to fresh sardines, which seemed to confirm the researchers' suspicions. Another study in April 2014 by the same team also came to these same conclusions. That study received a thorough review from peer researchers in the online journal Avian Conservation and Ecology. Work on a secondary study began in June 2017, which required the team to use the same method as their previous study. This research will ultimately help them put together time charts illustrating the population's size as well as offer an estimate of how many boobies will be able to successfully breed in the coming years. They'll also be looking at the possibility that sardine populations the water that divides the middle of the Galapagos archipelago may have recovered.

Two young brothers in Massachusetts founded an organization called The Blue Feet Foundation, which sells socks featuring a whimsical blue-footed booby theme. Sales of these socks continue to support this important research. As of June 2017, the foundation has donated $17,000 to the Galápagos Conservancy to fund this vital research.

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