Murrelets rely on each other to find breeding sites

In a new study from Oregon State University,  researchers have discovered that murrelets use eavesdropping to choose the best breeding locations. 

The experts played back recorded bird calls in forests and found that as the seabirds selected their breeding sites, they were strongly influenced by whether they heard other murrelets in the area.

With murrelet populations in a state decline, the research indicates that recovery could be hindered by the lack of nearby birds to provide information about where to nest.

Study lead author Jonathon Valente is a postdoctoral researcher with the College of Forestry’s Oregon Marbled Murrelet Project.

“The odds that marbled murrelets would consider nesting at sites where we broadcast murrelet calls were many times greater than at sites where we didn’t,” said Valente.

Unlike their close relatives, puffins and murres, marbled murrelets raise their young as far as 60 miles inland in old-growth forests.

“There aren’t many species like it,” said study co-author Jim Rivers. “In fact, there’s no other bird that feeds in the ocean and commutes such long distances to inland nest sites. This behavior is really unusual and it makes this species especially challenging to study.”

In 2016, the OSU team broadcasted bird calls at 14 potential breeding sites during mating season. Between the rounds of simulated calls, the experts recorded wild murrelet calls at the sites. These call rates were compared with rates at control sites where no recorded calls were broadcast.

The simulated calls increased the odds of recording wild murrelet calls by as much as 15 times. The scientists theorized that these were young “prospecting” birds, on the lookout for new nesting sites.

The researchers were surprised to discover that these prospectors remembered the locations of the experimental sites the following breeding season – nearly a year after the broadcasted calls had ceased.

The likelihood of murrelets occupying a site during the 2017 breeding season was 10 times greater if the recorded calls were played there the previous year.

“That means it would likely be a good idea for conservation managers to consider broadcasting vocalizations to encourage murrelets to nest in unused, high-quality habitat,” said study co-author Matt Betts. “And because murrelets are attracted to other murrelets, protecting areas adjacent to known nesting sites may also be an effective conservation approach.”

The study is published in the journal Ornithology.

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By Chrissy Sexton, Earth.com Staff Writer