Lousy sparrow neighbors
Male chipping sparrows (Spizella passerine) will trespass on the territory of their neighboring rivals to help them defend against invaders, but only if the newcomers are a bigger threat than the current neighbor, according to a paper published this week (February 26) in Biology Letters.
University of Massachusetts Amherst graduate student Sarah Goodwin and her advisor, Jeffrey Podos, played chipping sparrow songs on loud speakers near a fake sparrow rival. They found that male birds responded to a rival with a faster trill rate, indicating increased aggression. About 20 percent of the time, neighboring sparrows would come to the aid of the defending sparrow. But they only intervened when the trill rate of the defending neighbor was slower than their own, and when the intruding rival’s was faster than their current neighbor’s. Goodwin and Podos dubbed this the “dear enemy” strategy.
“We interpret this to mean that the ally not only prefers having a lousy neighbor, but also specifically does not want that lousy neighbor replaced by a more serious competitor," Podos said in a statement.
Dam adaptive toads
Study coauthor Jonathan Webb of the University of Technology Sydney and his colleagues fitted 20 toads with acoustic fish tags in two reservoirs in the Tanami desert. Underwater listening stations only pick up the signals these transmitters emit if the devices are submerged. When toads hopped out of the water, the signal was lost. The team found that toads visited the two reservoirs during the day, predominantly in the morning.
"No one has ever put fish tags on amphibians before to study their activity and what we found shows amazing behavioral flexibility on the part of these toads," Webb said in a statement.
Plotnik observed the elephants periodically for more than a year during both stressful and stress-free times. In stressful situations, such as when a snake, a dog, or an unfriendly elephant approached, the elephants flared their ears, erected or curled out their tails, and trumpeted or roared as a distress signal. Other elephants reacted by “adopting the same emotion,” Plotnik told ScienceNow, “just as we do when watching a scary movie together. If an actor is frightened, our hearts race, and we reach for each other’s hands.”
Plotnik noted that a potential limitation of the study was that it was conducted on captive elephants. "This study is a first step," he said in a statement. "I would like to see this consolation capacity demonstrated in wild populations as well."
Floating ant rafts
The University of Lausanne’s Jessica Purcell and her colleagues collected flood ants (Formica selysi) from the banks of the Rhone River in Switzerland. In the lab, the researchers flooded the transplanted ants, and found that the babies-on-the-bottom strategy resulted in a relatively high survival rate for both worker ants and the brood.
“The larvae and pupae are buoyant and not entirely submerged,” Purcell told National Geographic’s Weird and Wild blog. “They are also quite fat, which may be one characteristic that helps buffer them against cold-water conditions.”
Great tits have great memories
Other birds, such as jays and crows, are known to also have good food-storage memories, but unlike them, Great tits don’t cache their own food. The researchers suggested that thieving birds memorize food locations differently than hoarders do.
“The ability of observational memorization could be more important for non-hoarders than for hoarders, as this could increase their chances of survival especially when foraging conditions are bad,” Brodin said in a statement. “For example, after a blizzard, the access to stored food may be the difference between life and death.”