Usually, birds of a feather flock together—but in the Amazon, some flocks feature dozens of species of all shapes and colors. A new study by San Francisco State University biologists singles out one reason why these unusually diverse flocks exist: lookout species that call in alarm when they spot dangerous predators.
[...] To put that idea to the test, the team captured alarm-calling dusky-throated antshrikes (Thamnomanes ardesiacus) from eight mixed-species flocks in southeastern Peru and kept each bird in an aviary for several days.
After the team removed the antshrikes, birds in each flock responded in a matter of hours. In three flocks, birds retreated to areas of denser cover at the same vertical level in the forest, while in another the members joined new flocks high in the canopy, another area that affords more cover from predators. Birds in control flocks, where the researchers captured antshrikes but immediately released them, tended to stay out in the open. The team reported their results today in the journal Ecology.
The results support the idea that alarm-calling species might allow their neighbors to live in dangerous neighborhoods. "These flocks occupy a middle layer of the rainforest that's not quite the ground and not quite the canopy," explained coauthor Eliseo Parra, a lecturer and researcher at San Francisco State. "A lot of literature suggests that this area is more dangerous. There are more opportunities for a predator to be hidden and still have a quick flight path." Remove the antshrikes and their former flockmates are left exposed, so they retreat to safer habitats.
(Score: 2, Funny) by aristarchus on Thursday May 24 2018, @10:29AM (3 children)
Thank goodness there are no alt-right snakes in the amazon, or janrinock's rejection of a certain bird's warnings would be quite deadly. Like, Mickey Ninange Anaconda deadly. Just saying.
(Score: 2) by realDonaldTrump on Thursday May 24 2018, @06:43PM
The anaconda is a snake, a kind of snake. And so is Nicki Minaj. She's disgusting!
(Score: 2) by linkdude64 on Friday May 25 2018, @02:56AM (1 child)
The alarm birds would cry "TRIGGERED!" so often that it would become meaningless, and the whole flock would perish.
(Score: 3, Insightful) by aristarchus on Friday May 25 2018, @07:48AM
I hope you can find your "scared" place. Yes, I know it is usually called a "safe" place, but let us be honest, Soyletil to Soylentil.
(Score: 4, Interesting) by frojack on Thursday May 24 2018, @07:24PM
San Francisco State University must have a lot of junket money these days to take a team to the rain forest capable of capturing specific and wary birds in a mixed flock, just to see how the rest of the flock behaved. (in decades past, I suspect the native human population just shot the noisy squawkers so they could catch the more desirable birds.)
Closer to home, one Steller's Jay will spot a fox, cat, or coyote, (posing no risk to themselves or their nests) and summon a murder of crows (literally out of thin air) and the combination will set up such a racket warning every ground dwelling mouse, rabbit, bird, and drive the predator away. They will also mob birds of prey (which might in fact be a threat to their nests).
Crows and Jays are food stealing species that end up dominating any food source, but otherwise pose no risk to the the rest of the bird population or small ground animals. So the ground animals and song birds are more brazen and relaxed around these noisy birds.
But hey, its more sciencie to study the same phenomenon in the jungle.
No, you are mistaken. I've always had this sig.