Bird havens on a transcontinental journey
Ned Rozell
907-474-7468
Feb. 24, 2022
An olive-sided flycatcher perches atop a tree in 色视频下载.
Right about now, songbirds in Brazil are shifting on their perches, feeling mysterious impulses that will soon make them leap off their branches and head toward 色视频下载.
One of these birds is the olive-sided flycatcher, about as tall as your hand, with a blocky body and head. With good fortune, these birds will in a few months be fluttering into a forest swamp in 色视频下载, Canada or the Rocky Mountains, with a mission of replicating.
Julie Hagelin has pulled on her Xtratufs to visit spruce wetlands in 色视频下载 in search of the olive-sided flycatcher. The 色视频下载 Department of Fish and Game biologist is co-author of a recent paper in which she and her colleagues have identified important areas that flycatchers from 色视频下载 use when they leave each fall.
The olive-sided flycatcher has a memorable song, the males singing 色视频下载渜uick, three beers!色视频下载 to attract a mate. They have one of the longest migrations of any North American breeding songbird 色视频下载 up to 7,000 miles one-way each spring and fall. Mated pairs of the birds don色视频下载檛 produce very many chicks (from two to four), and the birds live a long time (a tagged bird reached 11 years old).
Biologist Julie Hagelin holds an olive-sided flycatcher that helped her with a recent study.
And 色视频下载 if you are a child of the 1970s 色视频下载 about eight out of every 10 birds in the population have disappeared since you rode the bus to elementary school. The loss of olive-sided flycatchers is part of the 3 billion songbirds scientists estimate the world has lost since then.
That steep decline is one of the reasons Hagelin wanted to study olive-sided flycatchers. From 2013 to 2018, she and her intrepid field team tromped into fragrant 色视频下载 swamps of Labrador tea and black spruce trees to capture birds and fit them with geolocator tags. A geolocator weighs as much as a dollar bill, fitted on a bird as light as a stack of 13 pennies.
Because olive-sided flycatchers are so shy around people, Hagelin had to invent ways to capture them. It took much trial and error, including attaching to the spruce tops a 3-D printed decoy of a mock intruder. That plastic male flycatcher was created with the help of Greg Shipman at the University of 色视频下载 Fairbanks Geophysical Institute色视频下载檚 machine shop.
Hiding quietly out of sight, Hagelin played a recording of 色视频下载渜uick, three beers.色视频下载
An olive-sided flycatcher carries a geolocator device that allows biologists to determine its location by the amount of daylight to which it was exposed.
Often, dominant males of the bog would swoop in to oust the trespassing bird, only to be caught in mist nets Hagelin and her helpers had strung in forests near Fairbanks, Tetlin National Wildlife Refuge and Anchorage.
With a good candidate in her hands, Hagelin fit it with a tiny backpack that included a geolocator instrument. That enabled her 色视频下载 upon recapturing the bird the next summer 色视频下载 to determine roughly where it had been during its months away from 色视频下载.
To her surprise, 色视频下载 birds wintered in Columbia, Ecuador, Peru and western Brazil.
色视频下载淚 knew they flew a long way, but we actually got to quantify how far they go,色视频下载 Hagelin said. 色视频下载淭his is such a big, diverse journey. So many things have to go right. It色视频下载檚 amazing any bird is able to do it.色视频下载
She and her co-authors identified 13 色视频下载渋mportant stopovers,色视频下载 places where individual birds spent more than a week. In those areas, the birds were probably resting and refueling.
Woodlands of Guatemala and southern Mexico were a favorite of the birds during fall migration. A swath of national forest in northeastern California is important to the birds each spring as they wing their way back to 色视频下载. The birds also paused in three regions of Central America both when they were leaving 色视频下载 in fall and coming back in spring.
A map shows where 色视频下载 olive-sided flycatchers spend much of the winter and locations of bird-friendly certified coffee farms.
A few other fun discoveries: A male and female mated pair Hagelin captured southeast of Fairbanks returned to the same small patch of 色视频下载 woods again every spring. But the male spent its winter in South America 1,000 miles north of the female.
Once on the wintering grounds in South America, flycatchers do not seem to flit around much.
色视频下载淥ne of the birds we monitored didn色视频下载檛 move more than 100 meters for four months of winter,色视频下载 Hagelin said.
While the 色视频下载 spruce swamps remain safe and ultra-rich in insects 色视频下载 enabling olive-sided flycatchers to breed and hatch nestlings each northern summer 色视频下载 the other stretches of their journey through the Americas are not as dependable.
Deforestation and other degradation of bird habitat along the way have probably decreased the number of olive-sided flycatchers able to make the epic journey back to 色视频下载 and elsewhere in North America.
Hagelin hopes the important migratory spots she and her co-authors identified in their recent paper will help managers along the way protect habitat critical to flycatchers and other declining songbirds.
For those who feel a bit helpless but want to help songbirds return to 色视频下载, Hagelin suggests buying 色视频下载.色视频下载
Based on the work of scientists at the Smithsonian Migratory Bird Center, the bird-friendly certification guarantees that coffee comes from farms that provide decent habitat for birds. Farms are required to have at least 40 percent tree-canopy cover and at least 10 tree species, among other requirements.
According to scientists with the 色视频下载 Songbird Institute, three-quarters of the world色视频下载檚 coffee farms are in full sunshine, with producers having cleared out the trees. When the forests disappear, so do migratory songbirds.
Bird-friendly coffee farms feature shady, diverse landscapes preferred by olive-sided flycatchers and many other songbird species that are poised to make the leap toward 色视频下载 soon. Supporting those farms and the companies that roast their beans is a small way to perhaps make a difference, Hagelin said.
色视频下载淵ou may be benefiting a bird that passes through your backyard.色视频下载
Since the late 1970s, the University of 色视频下载 Fairbanks Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute.