This Cuckoo Bird’s Crazy Journey Could Help Scientists Save Its Species
Chris the cuckoo has traveled more than 60,000 miles in the past four years, surviving freakish spring hailstorms, predators, and other hazards across 22 countries—including seven transits of the Sahara desert. Currently living in the Congo rainforest, Chris is expected back in the northern hemisphere next spring.
We know all this because for the past three and a half years, Chris has been toting a solar-powered satellite tag that transmits his location in nearly real time.
“The fact that the tag’s lasted so long, the bird’s survived so long, have been really special and quite surprising,” said Chris Hewson, a research ecologist at the British Trust for Ornithology, which manages the project. “Being able to follow successive migration cycles, and see the similarities and variations in those, is quite exciting.”
The BTO is trying to figure out why cuckoo numbers in the United Kingdom have declined by almost 75 percent in the past 25 years. While loss of habitat to development seems to be a factor, cuckoos spend only about six weeks of the year in the U.K. So researchers tagged Chris and four other cuckoos in 2011 to learn more about where they went and what conditions they faced the other 46 weeks of the year.
Today Chris is the only one of the group still sending back data and one of around a dozen cuckoos BTO continues to track as they migrate between the U.K. and their wintering grounds in the rainforests of Congo.
BTO has learned that the birds arriving in England during spring, like Chris, tend to migrate back to Africa via a route across Spain. It’s a flyway they didn’t know about before, where changing weather conditions thought to be linked to climate change, such as drought and spring hailstorms, have created new hazards for migrating cuckoos.
By contrast, cuckoos that depart from Scotland and Wales tend to take an easterly route over Italy and have shown better survival rates than their England-based counterparts.
This information has prompted Hewson and his colleagues to begin learning more about the habitat conditions that cuckoos encounter before crossing the Sahara and relate it back to how well they survive migration. “If we can get a handle on what the better stopover qualities might be, we can at that point make some recommendations,” he said.
In the United States, meanwhile, Project SNOWstorm began tagging and tracking snowy owls during the winter of 2013–2014, taking advantage of an unusually huge migration of snowies from the Arctic into the continental U.S. The birds are outfitted with solar-powered tags that transmit data over cell phone networks and save data for later transmission when a signal is not available.
The goal is to learn more about what the birds are doing—and what risks they face when they leave the far north for the more developed parts of North America, said Scott Weidensaul, a naturalist who works with Project SNOWstorm.
After a long summer with all the tagged birds out of cell-tower range in the Arctic, two of the project’s snowies have reappeared in the past couple weeks.
“The last time we had contact with Millcreek”—one of the returned birds—“was around April 23,” Weidensaul said. “We know now he moved very rapidly north, to the northeastern portion of Ungava Peninsula in northeast Quebec.”
Although climate change wasn’t a factor in last year’s snowy owl influx, they are “one of the species at greatest risk from climate change,” Weidensaul said. He noted that the warming Arctic environment is affecting their prey, such as lemmings. The project has also found some dead snowy owls contaminated with high levels of environmental toxins such as methyl mercury, which is emitted from coal-fired power plants.
Because they range across diverse habitats and different continents, migrating bird species such as snowy owls and cuckoos “are a perfect model for biodiversity conservation,” said Andrew Farnsworth, an information science research associate with the Cornell Lab of Ornithology.
Thanks to the latest generation of lightweight, powerful tracking tags—products of the same tech trends putting small, powerful cell phones in our pockets—Farnsworth said scientists are beginning to uncover the interconnections “in terms of species moving across space and time, and understanding the changes in those spaces.”