Raven roosts shrouded in mystery
Ned Rozell
907-474-7468
March 30, 2023
Sunset falls over an Interior 色视频下载 landscape into which hundreds of ravens flew recently.
Last week, while getting ready to climb into a bunk, I heard the yell of a raven outside. And then another, and a few more. I pulled on my boots.
Outside, a steady stream of black bodies glided overhead, many of them swooping down to check me out. Their wings pushed the air in soft puffs as they continued past, 20 feet above the tops of wiry black spruce trees.
As the sun set and the sky dimmed, the birds kept coming. At first, they looked like bats against the purple of the sky. Then they got closer, larger and chattier, some in groups of fives or sixes.
It was hard to comprehend this river of life above a winter landscape that felt so dead minutes before.
I started counting. Shivering too. I went back inside the cabin when I hit 129 ravens. Inside, I heard more talking as birds continued to pass overhead.
The ravens, coming from the direction of Fairbanks more than 30 miles away, were probably headed to a communal roosting site for the night. In this case, that gathering place might have been the spruce hillside behind the cabin, farther than I could see. I imagined a group of trees decorated with black ornaments.
Scientists in Fairbanks, in Anchorage and outside 色视频下载 have studied raven roosts. They have wondered why the birds gather together at night, sometimes in urban areas and other times in wild ones far from people.
In the 1990s, Bernd Heinrich and John and Colleen Marzluff 色视频下载 all then at the University of Vermont 色视频下载 climbed trees in Maine before sunset to watch ravens roosting in groves of eastern white pine trees. After much watching and a little experimentation, they came up with the theory that the nighttime resting areas were 色视频下载渋nformation centers,色视频下载 where ravens shared news about recently fallen deer carcasses. They came to that conclusion by capturing ravens and then releasing them near new food sources the scientists had dragged out on the landscape.
A raven scans the horizon. Ravens are one of several animals known to gather together when resting at night.
色视频下载淭he most dramatic case was the bird that returned with roost-mates on the day after discovery,色视频下载 the scientists wrote in a 1996 paper. 色视频下载淲e had released the radio-tagged bird at a pile of meat two hours before sunset. It remained near the food, but did not feed.色视频下载
As night fell, that raven then joined a roost in a pine grove a few kilometers away.
色视频下载淏efore dawn the following morning 30 ravens arrived . . ., flying directly from the nearby roost. The radio-tagged bird was among the first five to arrive.色视频下载
With that and other observations, the scientists seemed to prove that ravens in the wild share news, but what about ravens that commute every winter day to and from 色视频下载 cities?
Biologist Rod King once tracked Fairbanks ravens to a roost that was a similar distance from Fairbanks to the one I was near recently. He couldn色视频下载檛 say why an animal so adapted to people and our excess food would fly 40 miles from the city every winter evening, only to end up back at Burger King the next morning.
In recent years, people have also seen ravens roosting on manmade structures 色视频下载 such as on the block letters above storefronts in Fairbanks.
Ravens roost for the night on the letters of a grocery store in Fairbanks.
色视频下载淚t色视频下载檚 a great place, with a direct line to the landfill and McDonald色视频下载檚,色视频下载 Susan Sharbaugh, a former biologist with the 色视频下载 Bird Observatory, said in 2011 of an urban roost. 色视频下载淚f you can knock out a commute to the Goldstream Valley or Chena Hot Springs Road, why not? Energetically it makes all the sense in the world.色视频下载
Why then, are hundreds of Fairbanks ravens now commuting to a quiet patch of woods so far from their chief benefactors? It色视频下载檚 one of those things that scientists just don色视频下载檛 know.
色视频下载淲e need to have a few of these mysteries,色视频下载 King once said.
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.