Is one of the “increasingly unexpected results” of the convergence of global warming with urban development
What is obtained when a cuff with a green cage cross? It is not the beginning of a joke, but the theme of a new study that aims to describe a hybrid bird never before found in nature.
The big question that intrigues scientists, however, is: why is this mysterious bird?
“We believe it is the first observed vertebrate that has been a result of the expansion of the habitat of two species due at least in part to climate change,” says Brian Stokes, a doctoral student in Biology at the University of Texas in Austin (USA), and the first author of the study, published September 10 at Ecology and Evolution.
The lively cage of bright colors is found in parts of South and Central America, Mexico and a limited portion of the southern Texas. But since 2000, the territory of Tropical Ave has expanded hundreds of kilometers to the north-over 160 km and about 2 degrees of latitude-along Rio Grande and towards San Antonio, says study co-author Timothy Keitt.
Avid bird observers throughout the center of Texas took note, sharing sighting of emerald birds on social networks and in applications such as Ebird. Keitt, Professor of Integrative Biology at UT Austin, has been following his rapid expansion to the north since 2018. “They are quite unmistakable in the field,” he says to CNN. “We see a green cage and we know for sure it’s a green cage.”
Stokes joined Keitt’s project a few years later, capturing birds to gather blood samples for genetic analysis and loosening them back in the wild. While monitoring social networks in search of gaosy-landslides in May 2023, Stokes came across an intriguing publication in a Facebook group called Texbirds. A woman in the suburbs of San Antonio shared a photo of an unusual bird that did not look like any stakes or keitt had already seen.
“He noticed that this person had published a picture of this strange camper and immediately told me. We got into the car and went to look for him immediately,” says Keitt.
Both described their discovery as one of the “increasingly unexpected results” that arise when global warming and urban development converge to bring animal populations to new habitats. This, they wrote both, can lead to unpredictable interactions between animals – in this case, between a tropical species and a seasoned – and create ecological communities never before seen.
Bird of different feathers in Texas
Some attempts to capture the alleged hybrid of Balk and Gaio-green has been needed. Corvids-birds of a group that includes girls, crows and sea crows-are notoriously intelligent.
The investigators marked the mysterious bird and collected blood for genetic sampling. They observed that the object of the study had distinct characteristics of blue-gaosters and green girls-which are not so close and who separated from a common ancestor about 7 million years ago.
The bird had blue feathers on the back and tail and white spots on the wings, similar to those of the Blue Cattle. But I didn’t have the pointed crest of the Gaio-blue and had a stain on the eye, which is a revealing sign of the Gaio-Green. The atypical bird followed a bunch of slay-goios and emitted similar calls. But it also produced the clicks and boasting vocalizations of the Gaio-Verde.
Upon returning to the laboratory, Keitt and Stokes completed a series of genetic analyzes, comparing the DNA they had collected from a camshore, a green camper and other species of Gaios and determined that the mysterious bird was a descendant of a male caution and a female gay.
Another well-known example of a Gaio-blue and Gaio-Verde hybrid was born in captivity in the 1960s, when the natural reproduction places of the two species were separated by about 200 kilometers. The specimen is preserved in a museum collection in Texas and is very similar to the wildbird identified by the researchers.
The mating between a Gaio-blue and a Gaio-Verde is a “biological surprise”
Gavin M. Leighton, associate professor of biology at Buffalo State University, in western New York, who investigated hybridization trends among wild birds and did not participate in the study, was a little surprised by mating. According to Leighton, scientists tend to assume that hybridization arises from a case of wrong identity – two birds that do not realize that they are mating with a member of a different species. There are many hybrids among other types of poultry, but many are closer than these Gaios.
For Leighton, unusual pairing is a kind of “biological ball”.
“Both species of Gaios form lasting social ties with a partner,” he explains. “It is to be expected to be quite selective about choosing the partner with whom they form these ties.” In addition, the corvids are extremely intelligent and the bluebag and the green girls are quite different from each other. They should have no problem distinguishing each other from each other.
Perhaps it speculated Leighton, it was the end of the time of reproduction and the birds were under pressure. “If you are not lucky to find an individual in your own species who don’t have a partner either, then there may be a greater risk of making a mistake.”
Expand territories as temperatures increase
It is a mistake that could only have been made today, because it was only in the last 10 years that the areas of distribution of Gaio-Blue and Gaio-Green began to overlap. Blackhaels, found throughout the east of the United States, have advanced west, possibly following suburbanization and taking advantage of bird feeders in backyards.
However, recent increases in night temperatures in Texas may have made the region more hospitable to tropical species, which could explain the expansion of green girls to the north, according to Keitt (they are also frequent visitors of feeders). The two distribution areas converge around San Antonio – where the surprising hybrid was found.
“Species that may not have interacted for millions of years are suddenly contacting and we believe this is probably the result of anthropogenic factors such as climate change and habitat modification.”
Keitt is interested in seeing what will happen if the bluebye and green girls are increasingly sharing the same habitat. Will they fight with each other? Or will they ignore and coexist peacefully? One thing is likely: they will probably get better if they know who is who.
Amanda Schupak is a science and health journalist in the city of New York
