What’s Killing Migratory Birds? A New Tracking System May Offer Clues. – Mom Jones

Red knots of their breeding plumage feed at Golfo de Santa Clara, Mexico. Julián Garcia Walther/Undark

This story was initially revealed by Undark and seems right here as a part of the Climate Desk collaboration. 

Twice a 12 months, members of a subspecies of purple knots—salmon-colored sandpipers—migrate 1000’s of miles between their wintering grounds in northern Mexico and breeding websites within the Arctic tundra, encountering myriad obstacles alongside the best way. Thought emigrate throughout each day and evening, brightly lit cities possible disrupt their nighttime journeys, and rising sea levels and invasive species threaten the wetlands they depend on for refueling at stopover websites.

The purple knot is certainly one of some 350 North American hen species that migrate. Yet there stays a lot to study concerning the particulars of their journeys. It’s a essential data hole given the lack of an estimated 3 billion birds in North America since 1970, in keeping with a 2019 study.

“The only way to think about conservation of migratory birds is to consider their full annual cycles,” together with their migration routes and wintering websites, stated Bill DeLuca, a senior migration ecologist with the National Audubon Society.

The downside, he stated, is “We don’t know, for a lot of species, what time of the year is causing the declines.” For the overwhelming majority of migrating birds, the complete image of their life cycle is incomplete, DeLuca added.

That’s partly resulting from expertise. Until just lately, whereas scientists may examine birds at their North American breeding websites, they’d few methods to trace them individually all through their migrations or whereas of their wintering grounds, particularly small songbirds like warblers and sparrows.

And for birds that migrate via the West’s distant deserts and mountains and throughout its wild shorelines, just like the rufous hummingbird, which journeys between Alaska and the Pacific Northwest and Mexico, their flight routes are even much less understood. “Knowledge of migration patterns for birds in the West is way behind the East,” stated Mary Whitfield, analysis director on the California nonprofit Southern Sierra Research Station, due to the smaller variety of long-term banding stations there.

But scientists throughout the West are more and more turning to an accessible, low-cost expertise to reply key questions on hen migration and the way local weather change is impacting their life cycles.

The Motus Wildlife Tracking System, launched in 2014, is a world community of about 1,800 radio receiver stations in 34 nations. The program, run by the conservation organization Birds Canada, is already effectively established in japanese North America, however has begun to unfold quickly throughout the West within the final couple of years. Researchers within the Motus community observe birds (or different animals, like butterflies) utilizing small tags.

When a hen flies inside vary of a station—as much as about 12 miles away, relying on the circumstances—the tag mechanically transmits a sign to a receiver, which is then uploaded to the Motus web site. Scientists take part via tagging, building Motus stations, or each, and fund their very own initiatives. Museums, zoos, and faculties might also take part by internet hosting a Motus station and educating the general public about hen migration and motion, Whitfield famous. So far, greater than 43,600 animals, together with butterflies, bats, and birds, have been tagged by researchers utilizing Motus globally.

Until just lately, monitoring tags have been too massive and heavy for small songbirds. The Motus system makes use of tags that weigh lower than 3 p.c of a hen’s weight—within the case of a small songbird that weighs round 18 grams, a tag weighs simply half a gram. After birds are captured in mist nets fabricated from fantastic mesh, they’re fitted with the tags utilizing a harness, which they put on like a backpack.

An estimated 1 billion birds use the Pacific flyway, a route via Western coastal states, throughout their migration, and plenty of hundreds of thousands extra migrate by way of the central flyway via the inside West. Along the best way, they routinely encounter pure phenomena like storms, drought, and predators, in addition to man-made obstacles like glass-facades that entice birds and pose critical collision dangers. In addition, given the fast development of wind and photo voltaic initiatives throughout the West, Whitfield stated, it’s essential to establish birds’ actions via desert areas earmarked for different power improvement.

According to Whitfield, Motus (Latin for movement) might be a “game changer” for understanding Western birds’ actions via the seasons. “It’s critical,” Whitfield stated. “We have to find out more about migration, because it’s definitely a pinch point for bird mortality—that’s typically when birds die the most, because it’s just a really perilous journey.”

In May of this 12 months on the Bosque del Apache Wildlife Refuge in New Mexico, Matt Webb, an avian ecologist with the Bird Conservancy of the Rockies, was on the brink of set up a Motus radio tower with funding from the U.S. Fish and Wildlife Service. He hoped to fill “in some of the knowledge gaps” about grassland songbirds, that are experiencing fast declines in inhabitants. Four species specifically have declined greater than 70 p.c since 1970, in keeping with the hen conservation community Partners in Flight.

Grassland birds vary from the prairies of Saskatchewan to the southernmost edges of the Chihuahuan desert in Mexico. “We’ve got this massive geography that we need to cover adequately” to know their migration, Webb stated.

And the birds don’t simply journey throughout migration, he added—they roam broadly throughout each the breeding season and winter, making them much more troublesome to watch. With knowledge from Motus, Webb stated, they hope to “unravel some of those mysteries of why they’re moving around and where they’re going during those seasons.”

Webb was geared up with a number of lengthy antennas and a shoebox-sized, solar-powered sensor station laptop with mobile connectivity for receiving and transmitting knowledge. But the street to the tower website was flooded, after elevated snowpack drove excessive flows within the Rio Grande River.

So Webb and Kylie Lamoree, one other Bird Conservancy ecologist, turned to Plan B, surveying old water and communications towers as potential areas. In order to detect tagged birds as much as 12 miles away, “We need to get it up above the topography and the vegetation nearby,” Webb stated. (He later famous that they have been in a position to return on the finish of August and set up the station.)

At the northern finish of the Chihuahuan desert, Bosque del Apache National Wildlife Refuge is a serious vacation spot for migrating and wintering waterfowl in addition to for birders. Webb was searching for to find out if the 4 grassland birds he’s learning —thick-billed longspurs, chestnut-colored longspurs, Baird’s sparrows, and Sprague’s pipits—are utilizing the refuge through the winter, throughout migration, or each.

Those 4 species are small songbirds with ochre, tan, or black plumage that make them well-camouflaged in shortgrass prairie habitat. The birds are troublesome to seize for tagging with out massive vegetation to hide the researchers’ mist nets, Webb stated.

Even so, Webb stated the payoff is nice: “There’s really never been a technology that works well enough to be able to collect this data” for such tiny birds, he stated. And after a hen is tagged with its transmitter “backpack,” it doesn’t should be recaptured.

Migrating shorebirds are one other group of Western birds with steep inhabitants losses in recent a long time. Julián Garcia Walther, a Mexican biologist and Ph.D. scholar on the University of Massachusetts, Amherst, is monitoring shorebirds in northwest Mexico to search out out extra about local weather change impacts on sea stage rise and biodiversity. “I started thinking about how these birds that live on the interface between land and sea, the intertidal zone, how they’re going to be affected by sea level rise,” Garcia Walther stated.

He discovered about Motus in 2019, and realized the small tags used within the community have been preferrred for monitoring purple knots, lots of which winter within the coastal wetlands of northwest Mexico and whose populations are beneath stress. But there have been no Motus stations within the area.

Garcia Walther has now put in about 25 Motus stations with the assistance of the Mexican conservation organization Pronatura Noroeste, the place he’s the Motus community coordinator, together with different companion organizations. “It’s a big learning curve,” he stated, requiring abilities in electrical energy, radio communications, and development. One of his greatest challenges is sourcing supplies in Mexico, so he turned to improvised supplies, like a pole as soon as used for an osprey nest transformed into an antenna mast.

Another hurdle was capturing the birds. Without tagged birds, stations are “just poles and antennas,” Garcia Walther stated. Shorebirds are particularly tough to seize as a result of they disperse throughout the shoreline’s open expanses. While the harness technique used for tagging grassland birds can be usually utilized in shorebird analysis, Garcia Walther added, his workforce makes use of glue to safe the tags to the backs of purple knots, that means the birds will shed the units once they molt.

But with three years of knowledge from some 100 birds, Garcia’s workforce has made some vital observations. One discovering, the results of knowledge from Motus stations in addition to GPS loggers—trackers that present fine-scale actions—revealed that in excessive spring tides, purple knots use dried seagrass as rafts to relaxation on whereas the tidelands are inundated.

“This is analogous to what’s going to happen with sea-level rise,” Garcia Walther stated. The knowledge he has collected ought to assist wildlife researchers plan for the long run when there’ll possible be little shoreline available for roosting, he stated, informing methods to guard, restore, and enhance vulnerable habitats.

Garcia Walther stated he bought recommendation from colleagues within the US when he was establishing his stations, and he now helps scientists elsewhere in Latin America with their Motus initiatives.

Blake Barbaree, a senior ecologist at Point Blue Conservation Science with initiatives in California’s Central Valley, additionally relies on cross-border collaboration. His workforce is investigating the influence of drought on shorebirds, utilizing Motus to trace the actions of birds in California through the winter in addition to throughout migration.

Since they’re solely within the second season, Barbaree stated it’s too quickly to attract any definitive conclusions, although knowledge collected at Motus towers has confirmed excessive connectivity between the Central Valley and coastal Washington, in addition to the Copper River Delta in Alaska. “Numerous detections at Motus stations along the coasts of Oregon and British Columbia,” he wrote in a follow-up e mail, “have also highlighted the fact that a network of stopover sites is critical to their migration.”

This linkage, Barbaree stated, helps researchers “piece together puzzles of population increases or decreases,” in search of impacts not simply in wintering or breeding grounds however in key stopover habitats.

The community “has really opened up a world of migratory connectivity research” on different small animals like bugs and bats, Barbaree added. And he’s seen it encourage collaboration between researchers investigating not simply birds, however different migratory species.

Motus initiatives embody research on bats and bugs, for instance, with greater than 340 species tagged so far. And scientists are turning to Motus for assist figuring out threats frequent to birds and bats. In 2023, a team from the U.S. Geological Survey put in two coastal Motus stations in California—with plans to put in about two dozen extra—to watch three seabird species and three species of bats, to find out potential impacts of offshore power.

After a serious effort final winter to tag grassland birds in northern Mexico, Webb adopted their migration north within the spring—by way of knowledge their tags uploaded to the Motus web site. A Baird’s sparrow his workforce tagged was tracked from Chihuahua to northern Kansas and up via North Dakota and Montana, the primary time they’d related migratory stops via North American grassland habitats in such element. It was “a lot of fun this spring watching the stations every morning,” he stated.

DeLuca of the Audubon Society stated understanding the life cycles of various species is step one in revealing the components inflicting their decline, like habitat loss or air pollution. “When you think of all of the drivers that are pushing these species” in the direction of extinction, he stated, “it’s really kind of mind boggling.”

And local weather change, he stated, is a further “huge over-arching pressure,” because it impacts hen migration immediately with impacts like elevated extreme climate, and not directly when meals sources like fruit or bugs aren’t available.

Identifying the habitats birds depend on throughout migration and winter is vital, DeLuca stated.

And the Motus community can amplify these efforts.