![]() The most obvious sign that the parents are abandoning their chicks is finding the chicks on the cage or aviary floor. A fertile egg will clearly show a blood vessel network an embryo formed that resembles an opaque shape will be clearly visible. Hold the egg in front of a candle or strong light to observe for any signs of fertility. If the chicks do not hatch again, then check to see if all the eggs were fertile. Update, 18 August: An earlier version of this story contained an error about which group of birds produced fewer fledglings as adults.Watch your birds next time, but do it carefully so as not to disturb them. “What are we ignoring that is right before us?” “Zebra finches are literally right in front of us in cages around the world,” she says. Still, the existence of a previously overlooked finch call is a fascinating find, Kleindorfer adds. Noisy adult finches might attract predators, so the parental calls might endanger baby birds, she says. What seems like a useful warning in captivity, however, might prove deadly in the wild. “This is a remarkable study,” says Sonia Kleindorfer at Flinders University in Adelaide, Australia, because it shows how the sounds a bird hears in its egg can shape its development, even into adulthood. “It is surprising that vocal communication at such an early stage of development can have such persistent effects,” Duckworth says. ![]() Bird parents can influence their offspring in other ways, for example by changing the mix of hormones and nutrients that goes into the egg.īut using sound to teach their babies how to grow is something we didn’t know about before, she adds. Smaller birds may have an easier time shedding excess body heat, or perhaps the act of growing bigger is simply more stressful on birds’ bodies during hot weather, Mariette says.įiguring that out will be interesting, says Renée Duckworth at the University of Arizona in Tucson. ![]() The next step is to figure out what physiological changes are driving the chicks’ growth. “That’s a strategy we really didn’t know birds could do, and that could potentially help them deal with global warming,” she adds. The parental calls, and their chicks’ reaction to them, can make the finches more productive as adults, says Mariette. The chicks from that group that didn’t follow their parents’ advice typically only had one or two fledglings. The chicks that hadn’t heard the song were the opposite: those in the hotter nests grew to be heavier.Īs adults, the female finches that had heard the warm weather song and grew accordingly produced up to six fledglings during their first breeding season. Of the chicks played the warm-weather song, those that grew up in hotter nests tended to weigh less than those raised in cooler nests. Mariette and Buchanan returned about 170 hatchlings to nests scattered around the aviary, some of which were sunnier and so warmer than others. During the five days before the chicks hatched, the researchers played recordings that included the hot-weather song to about half of them, and the same recordings, minus the hot-weather calls, to the rest. ![]() To see if the eggs were listening, the scientists incubated a group in the lab. ![]() What else can we learn from birds? Birds do impressions – it’s time to take them seriously ![]()
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