The screech owls are an interesting and diverse group of birds. Restricted solely to the Americas, they are generally very small owls, with even the largest failing to exceed 10 inches in height. Many have incredible camouflage, with feathers that incorporate a range of brown, grey and pale colours, helping them to blend in effortlessly to their arboreal environments. Despite what their name may suggest, screech owls do not communicate in screeches or screams, instead of calling to one another using short trills.
Until recently, 21 screech owl species had been identified across the Americas. That number has now risen to 23, with the discovery of two new species from the forests of Brazil. A group announced international ornithologists via a paper published in the journal Zootaxa.1
The screech owl genus has long perplexed scientists, with many of its species being almost impossible to tell apart based on physical appearance. This makes their identification very difficult indeed, meaning the researchers had to take a novel approach to distinguish between their avian subjects.
The screech owl genus has long perplexed scientists, with many of its species being almost impossible to tell apart based on physical appearance.
When it comes to species identification, appearances can be deceptive. For example, rock hyraxes – which are small mammals native to Africa – very much resemble rodents. But in fact, these furry creatures are one of the closest living relatives to the elephant, an animal that is vastly different in size and morphology. The result for scientists studying this sort of thing is a taxonomic nightmare. The screech owl genus has proved an especially troublesome headache for many years, constantly being lumped together or split apart. As stated by Alex Aleixo – head of the research team responsible for the study – "Not even professional ornithologists who have worked on owls for their entire lives would agree about the actual number of species found in this group, so a study like ours has been awaited for a long time."
The implementation of genetic techniques such as DNA sequencing has vastly improved the ease at which formal identification can occur. Still, it is always helpful to use all the resources available. Part of the team’s research involved analysing tape recordings of a select group of South American screech owls with an uncertain number of species. The recordings captured the trilling calls of the owls, which were then played back in the field. Screech owls are territorial creatures. Each species varies in the vocalisations it produces, meaning the team obtained from observing the birds’ reactions could be used to inform identification.
Combined with genetic analysis, the researchers described two new species – the Xingu screech owl (Megascops stangiae) and the Alagoas screech owl (Megascops alagoensis).2
Despite being new kids on the block, there is already concern over the future of these two species. The Alagoas screech owl has only been found in a few isolated regions in Brazil’s Atlantic Forest. Only a tiny proportion of this forest is under legal protection, leaving it exposed to activities such as logging and farming. These practices have a strong association with deforestation, which reduces the amount of available habitat and fragments it in a way that makes it difficult for some species to survive. The more isolated populations of the Alagoas screech owl become, the less likely they will be to find suitable mates or feeding opportunities, eventually leading to a decline in numbers.
The outlook for the Xingu screech owl is similarly lacking. It is restricted to a tiny area of the Amazon Rainforest, which suffered extensive damage after fires raged through in 2019. Over 310,000 acres of the Brazilian Amazon were destroyed in that year alone, with experts highlighting a solid link between deforestation in the region and an increased fire risk. Unfortunately, this suggests that extreme events such as these are likely to continue in future.
Amidst this environmental turmoil, both the Xingu screech owl and the Alagoas screech owl will likely be classified as critically endangered. Without preventative methods and better land management practices, these two new screech owls may well go extinct – a loss not only for the researchers who have spent so many years studying them but also for global biodiversity as a whole.3
Dantas, S.M., Weckstein, J.D., Bates, J., Oliveira, J.N., Catanach, T.A. and Aleixo, A., 2021. Multi-character taxonomic review, systematics, and biogeography of the Black-capped/Tawny-bellied Screech Owl (Megascops atricapilla-M. watsonii) complex (Aves: Strigidae). Zootaxa, 4949(3), pp.401-444. ↩
Motta-Junior, J.C., Braga, A.C.R. and Granzinolli, M.A.M., 2017. The owls of Brazil. In Neotropical owls (pp. 97-158). Springer. ↩