[Tweeters] News from Cornell - new northern flycatcher discovered

Michael Hobbs birdmarymoor at frontier.com
Fri Apr 1 07:50:13 PDT 2016

I saw this on the Cornell website, and thought it was quite interesting. -- Michael Hobbs, Kirkland, WA

A new species of flycatcher has been discovered in the high tundra, that lives like the insects it feeds on. Researchers have named it the Tundra Flycatcher, Ficedula gelidova, as it was previously believed to be a subspecies of the Taiga Flycatcher which it greatly resembles morphologically. “The best way to tell them apart, visually, is that the Tundra Flycatcher has relatively shorter wings,” reported Sarah Snow, who led the research team from the University of Alaska. “But while they look almost identical, the similarities pretty much end there,” she added.

Unlike it's close relative, which overwinters all across southeast Asia and the Indian subcontinent, the Tundra Flycatcher’s wintering grounds were unknown. Scientists had no idea where they went after the short arctic summer. Attempts to track this failed with baffling results. “Birds were banded for more than 20 years on nests, yet a banded bird was never spotted anywhere away from the arctic tundra. So we tried radio tagging. All of the tags seemed to fall off the birds before they migrated,” Snow explained.

That turned out to be a huge clue. Researchers began to investigate previous-year’s nests to try to understand what was happening to the radio tags, and found the tags and the leg bands and partial skeletons from the birds they’d studied the year before. “We’d band only one of the pair – either the male or the female – but we were able to recover not just the radio tag, but the leg bands from both birds of the pair. It appeared that every bird died on the nest!”

It took three more years of research for Snow’s team to piece together the rest of the story. Rather than migrate thousands of miles to warmer climes for the winter, the Tundra Flycatcher appears to have developed a lifestyle that mimics many of the arctic insects that it feeds on during the short arctic summer.

“Sunlight shining twenty-four hours a day provides a huge amount of energy in the high arctic,” Snow explained. “In a very short period of time, a multitude insects hatch from eggs laid the summer before. Plants sprout from seeds set the summer before. It’s an incredible bloom of life taking place over a matter of a very few weeks. All of the other arctic-breeding birds time their migration to take advantage of this explosion of food resources.”

But not the Tundra Flycatcher. Like the insects and plants, it appears to have evolved an annual life cycle that is very short but efficient. Eschewing migration, this flycatcher builds extensive nests to protect it’s eggs, which it lays very late in the arctic summer. The adult birds then nestle into the nest and die there. The eggs overwinter, and are warmed in the spring by warmth from the sun, hatching early in the arctic summer. The precocial young feed themselves on the abundant insect swarms that are, themselves, hatching from overwintered eggs.

“This makes them the only bird species with an annual lifecycle,” reported Snow. “They quite possibly belong in their own genus.” But for now, she’s proposing they remain part of the Ficedula genus which they physically resemble so closely. “Even their song is similar,” Snow added.

Their results are appearing in the April edition of Science.
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