Biology student braves hurricanes and sharks on remote Pacific island

Roberto Sosa has been to some remote corners of Mexico on his quest to learn more about the songs of the wren, but says nothing compared to the month he spent this summer tracking the birds on an isolated jungle island in the middle of the Pacific Ocean.

“In my personal experience, this was one of my best field seasons in terms of data collection,” said Sosa, a PhD student in associate professor Dan Mennill’s lab in biological sciences.

Originally from Pijijiapan, a town of about 40,000 in Chiapas, Mexico, Sosa spent most of August on Isla Socorro, part of the Archipelago de Revillagigedo, located about 400 km southwest from the tip of the Baja Peninsula. The tiny island, formed by volcanic rock, is about 16 km by 11 km, and home to a Mexican naval base which includes about 200 sailors. There’s only one road that connects the base to an air strip, and the rest of the island is mostly jungle.

“It’s very harsh conditions,” said Sosa.

Sosa studies the evolution of bird songs, analyzing their frequency, timing and general structure. He says the birds – a species of the Troglodytes genus – have certain dialects that inform scientists where they’re from. He’s trying to determine if there are even particular rules of syntax they follow and says the logical next step for his research would be to figure out if there’s certain information they try to communicate and if that can be determined by the structure of the song.

For his field work, Sosa travels out in to the jungle with a complex array of digital equipment to record the birds while they’re singing. On Socorro, he used the naval base as his main quarters, but would head out with a small team of other scientists, camping in the jungle for three or four nights at a time and capturing his recordings.

“On the islands, birds are not so afraid of people,” said Sosa, who holds a scholarship from Consejo Nacional de Ciencia y Tecnología, Mexico’s equivalent of NSERC. “They would come very close to you.”

On two occasions, sailors from the naval base had to come out to find them in the jungle and help them return due to hurricane warnings. The first was downgraded to a tropical storm by the time it hit the island, but Sosa said he still experienced heavy rains, gale force winds and high waves at the base. The second arrived during the final days of his trip and was much more intense.

“I woke up my friend at about 3 a.m. because I thought the frame was coming right off the door,” he said.

Most of the weather, however, was ideal and Sosa said he managed to have some fun while he was there. A highlight was the chance to go snorkeling in a secluded bay in the presence of turtles, tropical fish and some rather large reef sharks. He was fascinated by the animals, but approached them with a healthy dose of caution.

“You want to follow the shark, but you’re afraid at the same time,” said Sosa, who earned his undergraduate degree and master’s degree in biology from the Universidad Nacional Autónoma de México in Mexico City. “We got within about three metres. They are aggressive, so you have to be careful.”

Now that he’s back in the lab, Sosa is busy analyzing all the data he collected during the trip and reflecting back on his summer.

“It was a great experience,” he said. “I’ve had a lot of unusual experiences on this island.”

Editor's note: this is one of a series of articles about students who were engaged in cool research projects and other scholarly activities during the summer.

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