With no land predators trying to snatch away eggs for an easy dinner, and a scientific station run by Bowdoin University in Maine for nearly 90 years, Kent Island has become the home of some of the longest-continuing species studies in the world.
The only mammals on the island, a tiny spot in the Bay of Fundy off the southeast coast of Grand Manan, are muskrats and scientists. That has allowed it to become a haven for nesting birds and the people who study them.
Every day, Patrica Jones ventures out into a small, forested area of Kent Island known as the shire. Under the ground are hundreds of tiny burrows. Some have little sticks lined up blocking their entrance. Some do not. All of them have a little metal medallion with a number hanging outside.
“Birds don’t mind knocking over some sticks to go in,” said Jones.
She checks her paper map and finds a burrow where there are no twigs blocking the entrance. That means something’s inside. Lying on the forest floor, she pushes her hand into the burrow all the way up to her shoulder. When she pulls it out, she’s cupping a small grey bird with a black beak: a Leach’s storm petrel.
The seabird has travelled to Kent Island from the southern coast of Africa to lay a single egg underground. Jones measures its wings and feet and weighs it, noting the number on a band on its leg. She also takes measurements of the small egg she also pulled from the burrow. Everything she records is handwritten.
The process takes several minutes, all part of a study that has been running since 1953, with a bit more data dating back to the 1930s.
“We’ve got this really amazing — one of the longest data sets on a vertebrate animal in the world,” said Jones, who is the director of the Bowdoin Scientific Station on Kent Island.
Because the storm petrel study on this island has been going on for 70 years, Jones and her predecessors have been able to track the health of the small seabird population, made up of about 20,000 mated pairs.
“We can track impacts on climate on egg-lay date and egg-hatch date and egg-hatch success,” said Jones. “There are a lot of variables that we’ve been tracking for a long time here with this population.”
That includes where the birds go.
GPS trackers show parents take turns caring for their single egg. One will stay with the egg while the other travels to Cape Cod, Mass., about 400 kilometres away, to feed for a few days.
“Then come back here to this tiny island to their little burrow in the ground and sit on their eggs for another three days,” said Jones.
The birds have a long life, with Kent Island records showing they live to be at least 36 years old. Jones says they know the petrel population is in decline, not unlike most seabird species.
Leaving the shire and crossing the basin on Kent Island leads to the grasslands. Savannah sparrows dart through the grasses where they’ve laid their eggs. Research on these small songbirds has been ongoing for the last 36 years.
“This study has been running since 1987,” said Sarah Mueller, a PhD candidate at the University of Guelph. “They’ve done a lot of different things — migration studies, different studies of breeding biology and success and that kind of thing.”
Mueller goes from nest to nest, noting how many eggs are in each. When they hatch, she scoops them up to take measurements, weigh them and take a blood sample before carefully returning them to the nest.
She’s been working on the study for the last two years as just one of a series of researchers contributing to the long-term data on the population.
“Some of the things they’ve been able to do with that really long-term data is look at drivers of population growth and decline,” said Mueller.
She says researchers learned that competition for territory and resources, as well as winter survival, seem to have large impact on the population, which, like the petrel, is also on the decline.
Mueller’s currently studying the most common causes of death for the young swallows, as well as how far they typically venture from their nests.
“I’ve found that about 33 per cent of fledglings make it to about three months,” said Mueller. “Which seems pretty low, only 33 per cent of fledglings survive … but fairly comparable to other songbird studies.”
On a beach near the sparrows, two more researchers plant herring gull decoys near nests.
“Only the fun part of my work takes place here out in the field,” jokes Liam Taylor, an evolutionary biologist working on his PhD at Yale. “We’re interested in a different kind of question: what does breeding in a colony do to a bird? And how does it maybe reshape their evolution?”
Taylor says they’ve found young gulls will return to the Kent Island breeding colony years before they’re actually able to breed, and scientists don’t yet know why. So they’re recording how parent gulls react to having younger gulls, that don’t seem to have an obvious role in the colony, near their young.
They place decoys with various feather patterns that indicate the gull’s age near a nest and record the reactions.
“We give it two minutes and it can be from anything from just, like, they fly away, sometimes they circle. Sometimes they peck at the decoy or, like, kick it,” said Lily Fanburg, a psychology major at Bowdoin University.
She has to dodge incoming gulls that will sometimes try to bomb her with poop as she retrieves the decoys and the wireless speaker that plays gull calls after each trial.
“It’s very different from my previous summer research experiences,” said Fanburg.
Researchers here will stay throughout the summer, with the last ones leaving in October. But they’ll return in April, just as they have since 1936.