Green-rumped parrotlets seem to have high rates of both adoption and infanticide. adoption and infanticide demonstrate two contrasting aspects of life in the animal kingdom. A study released on May 6 in the journal Proceedings of the National Academy of Sciences (PNAS) explains what leads them to exhibit these two extremes in dealing with the chicks of another bird.
Green-rumped parrotlets (Forpus passerinus) are a a very small and sociable bird found in parts of South America and the Caribbean. They consume fruits, seeds, and various flowers and are recognized for their vibrant green color. In contrast to other parrots that prefer to reside higher up in the forest canopy, Green-rumped parrotlets tend to make their nests in hollowed-out trees or fence posts in grasslands. These parrotlets are not the only animals observed to adopt or
kill the offspring of others . Numerous species ofamphibians, fish, rodents, felines, and primates have all been observed to kill the offspring of their own species and–in some cases– their own offspring. Both males and females may kill the offspring of their rivals in order to secure a social or sexual advantage for themselves. A male animal may kill the offspring of a female whose mate has died so that he canreproduce with her more quickly . Others have been observed caring for the offspring of deceased or missing animals.What occurred when scientists trained parrots to video chat?
“Most of the infanticide attacks occurred when a breeding pair was targeted by another pair attempting to take over a desirable nest site,” stated study co-author and University of California, Berkeley conservation biologist Steven Beissinger
In the studyrelationships . They discovered dead baby birds in the nests with no clear indication of the cause of death.“We couldn’t distinguish if something had attacked them, or if they had succumbed to illness, or something else,” said Beissinger. “But while we were observing some of the nests, suddenly a male who did not belong— who was not a parent in that nest— went in and emerged with a little blood on his beak.”
The team began to track occurrences of the behavior and also referenced
observations of over 2,700 nests taken between 1988 and 2015 in the study. Among parrotlets, it seems that competition for nesting sites is the primary incentive for the attacks, rather than reproduction. In the nests monitored by the team, parrotlets killed or injured nestlings and eggs at 256 sites. Most of the attacks seemed to be carried out by a single parrotlet or a breeding pair that came in and claimed the nesting site for themselves afterward. The attacks also happened more frequently when the parrotlet population was high and there was more competition for suitable nesting sites.
A parrot that cannot fly is coming back to main New Zealand after being away for 40 years.
“Not everyone is born to kill, but the desire to have babies is very strong,” said Karl Berg, a co-author of the study and an avian ecologist at the University of Texas Rio Grande Valley..]
This quote comes from a statement made by Berg. When food and other resources are not enough for all animals to have babies, they look for other ways. Sadly, this involves killing young animals that haven't done anything wrong.There were also cases of infanticide in nests where one parent had died and the other parent had found a new partner.
Infanticide was seen even when one parent had died and the surviving parent had found a new mate. The new mates were just as likely to adopt young animals that were not related to them or to kill them.Deciding to be a step-parent did not stop them from having babies of their own. Males who adopted chicks that were not related to them and lived with females also started having babies at a younger age.The team said that adoption is hard to understand because it challenges old ideas about natural selection.
Most animals want to pass on as many of their genes as possible to the next generation. Adopting a niece or nephew might make sense because they share about 25 percent of your genes. However, the advantage of adopting the offspring of an unrelated animal does not make as much sense, but it still happens.“It was very interesting to see that the reproductive fitness outcomes were about even between adoption and infanticide and suggests that they have an alternative strategy,” Berg said. The green-rumped parrotlets have the ability to be caregivers or killers.. An evolutionary goal for most animals is to get as many copies of your genes into the next generation as possible. Adopting a niece or nephew may make biological sense since they share roughly 25 percent of your genetic material. However, the advantage of adopting the offspring of an unrelated animal does not make quite as much sense, but still occurs.
“It was very interesting to see that the reproductive fitness outcomes were about even between adoption and infanticide and suggests that they have an alternative strategy,” said Berg. “Adoption may be a non-violent means of getting genes into the next generation.”
