For all humankind's discoveries, perhaps one of the most pleasing unfinished puzzles for zoologists and wildlife fanatics alike is the gaps in our knowledge about what animals share the Earth with us. Biodiversity hotspots like Madagascar continue to spit out species never before recognized by science, and one such discovery in South America has delivered not one but two new species of owls. The study, published in the journal Zootaxa, describes two screech owls (cousins of the Eastern Screech Owls that are common in the United States) that live in the Amazon and Atlantic forests. Unfortunately, both birds are already critically endangered, but they constitute two exciting pieces in the ongoing puzzle of our planet.
The birds’ calls were a crucial tool in establishing their species, collected from years of fieldwork in the Amazon rainforest and Atlantic forest on the eastern side of Brazil and nearby countries. The birds they wanted to get a better understanding of were nocturnal, and carrying out fieldwork in one of the most biodiverse habitats on the planets comes with its own unique perils.
"For me it's more a feeling of fascination than being scared, but at the same time, you're running into spider webs. If you're wearing a headlight you see the eyeshine of the nocturnal animals. One time I was stepping over a log and I looked down and there was a tarantula the size of my hand just sitting there," said John Bates, curator of birds at the Field Museum in Chicago and one of the study's authors in a statement. "If I had been a kid I would have been scared to death."
To make matters even harder, their preferred hangouts sit around a hundred feet above the forest floor. But armed with problem-solving brains and recording devices, the researchers were able to lure out their subjects by playing their screeches back at them. Screech owls are territorial, and if they catch wind of a screech owl screeching in their screeching grounds, you can bet they’re going to go and screech right back at that screech owl – be it bird or machine.
Combining the differences in these calls – as well as the birds’ physical appearance, and tissue samples collected in the field – the team was able to prove that their birds were, in fact, two distinct species. All in all, they had 252 specimens, 83 tape-recordings, and 49 genetic samples from across the range of the Tawny-bellied Screech Owl complex in South America to work from. This was made up of contributions from the team on the paper as well museum collections gathered over centuries.
Genetic data combined with the physical differences and unique calls of screech owls enabled the team to pin down the two new species: the Xingu Screech Owl and the Alagoas Screech Owl. The scientific name of the Xingu Screech Owl was chosen to honor Sister Dorothy May Stang, an activist who helped farmers fight for their land near the Xingu River, where the bird is found. Alagoas was chosen for the other as a reference to the northeastern Brazilian state in which it’s primarily found.
Both birds earned their unfortunate threatened status due to deforestation and habitat degradation, both from anthropogenic activity and the unprecedented forest fires which ripped through the canopy in 2019. The researchers hope their work will contribute an already thick body of evidence that more needs to be done to prevent more trees being cut down in this ever-shrinking biodiversity hotspot. "If you just say, 'Well, you know Amazonia is Amazonia, and it's big,' you don't end up prioritizing efforts to keep forests from being cut in these different parts of Amazonia,” said Bates. “That could mean losing entire faunas in this region.”