From Texas to Tennessee: Burrowing owl makes odd migration

A burrowing owl is overwintering on a Tennessee River peninsula near New Johnsonville, Tennessee, marking the first sighting of the species in the state.

STARKVILLE, Miss.—Birds migrating from north to south are a given but migrating from the southwest to the southeast is a little rarer. A burrowing owl is overwintering on a Tennessee River peninsula near New Johnsonville, Tennessee, marking the first sighting of the species in the state, and a Mississippi State wildlife ecologist is researching the fascinating oddity.

As the burrowing owl made its first home on a former Tennessee Valley Authority fossil fuel plant in 2020, Scott Rush, a scientist in the MSU Forest and Wildlife Research Center, was called in by TVA to study the bird of prey found hundreds of miles outside of its range.

“Burrowing owls are found west of Central Texas and Oklahoma, all the way up into Canada. There is also a non-migratory population in Florida, so you’ll occasionally see them in Alabama but never in Tennessee,” Rush said, explaining a continuing struggle for the birds is a loss of habitat.

Burrowing Owl, Athene cunicularia, observed overwintering in New Johnsonville, Tennessee, USA. Photograph taken on 19 November 2022 by T. Ross.

“They live inside burrows created by prairie dogs and other animals,” he said. “They’re declining across the range in part because we’re losing some of those historic systems like undisturbed prairie dog colonies as more grasslands are being developed.”

Rush, an associate professor in MSU’s Department of Wildlife, Fisheries and Aquaculture, and his research team have studied the bird and its diet to learn more about where the novel creature came from and why he makes his winter home in the Volunteer State.

Burrowing owl on the former TVA fossil fuel plant near New Johnsonville, Tennessee. Photo via MSU

The team collected plumage from the owl’s feathers and determined it was a male belonging to the subspecies A.c. hypugaea. They studied pellets to determine its diet, identifying six different species including insect, mammalian and plant remnants. They also conducted an isotopic analysis of its feathers to determine the bird’s home range. Details from the sightings were recently published in Check List, a journal of biodiversity data.

“We could see from various kinds of elemental components that the bird is probably from Texas, relatively near Dallas, according to our analysis,” said Rush, who noted the bird has been banded and this year, scientists hope to outfit it with a GPS tracker. “If we can put a GPS tracker on the owl, we can confirm its home range.”

The owl, which again has overwintered this season in the same location, was first spotted by a TVA employee, and Liz Hamrick, a terrestrial zoologist with TVA reached out to Rush.

A burrowing owl. Photo by Moisés Silva Lima shared under a CC BY 2.0 license

“A security guard at the site who happened to be an amateur birder came across it. Once I was alerted of its presence, I connected with our natural resources team who had already been working with Dr. Rush studying ospreys and vultures,” Hamrick said. “My role is to review TVA’s actions and ensure potential impacts to common wildlife and rare animals are avoided or minimized, and that includes protecting this owl. We need to make sure we follow all the state and federal laws, including the Endangered Species Act and the Executive Order for Migratory Birds.”

Hamrick said that as species assemblages change geographies, her team must be vigilant in identifying new species moving to the area like the burrowing owl and doing their best to protect them on TVA sites.

“It’s been exciting to learn about a whole new species and try to solve a mystery of why on earth this bird is repeatedly selecting to come to this industrial site out of its normal range,” she said.

Research article:

Rush SA, Naveda-Rodríguez A, Hamrick EB (2023) New overwintering location of Burrowing Owl, Athene cunicularia hypugaea (Molina, 1782) (Strigidae) in Tennessee, USA, with diet assessed through pellets. Check List 19(6): 863-868. https://doi.org/10.15560/19.6.863

This news piece was originally published by Mississippi State University. It is republished here with permission.

New species of owl discovered in the rainforests of Príncipe Island, Central Africa 

The Principe Scops-Owl, the eighth known bird species endemic to the island, has a unique call and lives in a restricted range in the Príncipe Obô Natural Park.

A new species of owl has just been described from Príncipe Island, part of the Democratic Republic of São Tomé and Príncipe in Central Africa. Scientists were first able to confirm its presence in 2016, although suspicions of its occurrence gained traction from 1998, and testimonies from local people suggesting its existence could be traced back as far as 1928. 

Otus bikegila. Photo by Martim Melo

The new owl species was described in the open-access journal ZooKeys based on multiple lines of evidence such as morphology, plumage colour and pattern, vocalisations, and genetics. Data was gathered and processed by an international team led by Martim Melo (CIBIO and Natural History and Science Museum of the University of Porto), Bárbara Freitas (CIBIO and the Spanish National Museum of Natural Sciences) and Angelica Crottini (CIBIO).

Bárbara Freitas, Bikegila and Martim Melo pose with an owl. Photo by Martim Melo

The bird is now officially known as the Principe Scops-Owl, or Otus bikegila.

Otus” is the generic name given to a group of small owls sharing a common history, commonly called scops-owls. They are found across Eurasia and Africa and include such widespread species as the Eurasian Scops-Owl (Otus scops) and the African Scops-Owl (Otus senegalensis). 

Bikegila. Photo by Martim Melo

The scientists behind the discovery further explain that the species epithet “bikegila” was chosen in homage of Ceciliano do Bom Jesus, nicknamed Bikegila – a former parrot harvester from Príncipe Island and now a ranger of its natural park. 

“The discovery of the Principe Scops-Owl was only possible thanks to the local knowledge shared by Bikegila and by his unflinching efforts to solve this long-time mystery,” the researchers say. “As such, the name is also meant as an acknowledgment to all locally-based field assistants who are crucial in advancing the knowledge on the biodiversity of the world.”

Martim Melo and Bikegila. Photo by Alexandre Vaz

In the wild, the easiest way to recognise one would be its unique call – in fact, it was one of the main clues leading to its discovery. 

Otus bikegila‘s unique call is a short “tuu” note repeated at a fast rate of about one note per second, reminiscent of insect calls. It is often emitted in duets, almost as soon as the night has fallen,” Martim Melo explains.

Otus bikegila’s call. Recording by Martim Melo

The entire Principe Island was extensively surveyed to determine the distribution and population size of the new species. Results, published in the journal Bird Conservation International, show that the Principe Scops-Owl is found only in the remaining old-growth native forest of Príncipe in the uninhabited southern part of the island. There, it occupies an area of about 15 km2, apparently due to a preference for lower elevations. In this small area (about four times the size of Central Park), the densities of the owl are relatively high, with the population estimated at around 1000-1500 individuals.

The difficult terrain of the uninhabited southern forests of Príncipe Island, home to the Príncipe Scops-Owl, was somewhat immortalised by José Correia, Portuguese collector for the American Museum of Natural History, when collecting there in 1928. He wrote in his diary: “I have been in very bad fields ready, but this is bad among the bad or worse among the worse”. Photo by Alexandre Vaz

Nevertheless, because all individuals of the species occur in this single and very small location (of which a part will be affected in the near future by the construction of a small hydro-electric dam), researchers have proposed that the species should be classified as ‘Critically Endangered’, the highest threat level on the IUCN Red List. This recommendation must still be evaluated by the International Union for Conservation of Nature.

Otus Bikegila. Photo by Martim Melo

Monitoring the population will be essential to get more precise estimates of its size and follow its trends. For this purpose, a survey protocol relying on the deployment of automatic recording units and AI to retrieve the data from these has been designed and successfully tested.

“The discovery of a new species that is immediately evaluated as highly threatened illustrates well the current biodiversity predicament”, the researchers say. “On a positive note, the area of occurrence of the Principe Scops-Owl is fully included within the Príncipe Obô Natural Park, which will hopefully help secure its protection.”

A view of the owl’s habitat. Photo by Martim Melo

This is the eighth known species of bird endemic to Príncipe, further highlighting the unusually high level of bird endemism for this island of only 139 km2.

Otus Bikegila. Photo by Paul van Giersbergen

Even though a new species of scops-owl was just described from Príncipe, genetic data indicated that the island was, surprisingly, likely the first in the Gulf of Guinea to be colonised by a species of scops-owl.

“Although it may seem odd for a bird species to remain undiscovered for science for so long on such a small island, this is by no means an isolated case when it comes to owls,” the researchers state. “For example, the Anjouan Scops-Owl was rediscovered in 1992, 106 years after its last observation, on Anjouan Island (also known as Ndzuani) in the Comoro Archipelago, and the Flores Scops-Owl was rediscovered in 1994, 98 years after the previous report.”

 “The discovery of a new bird species is always an occasion to celebrate and an opportunity to reach out to the general public on the subject of biodiversity,” says Martim Melo. “In this age of human-driven extinction, a major global effort should be undertaken to document what may soon not be anymore,” he and his team state in their paper.

Otus bikegila. Photo by Philippe Verbelen

“Birds are likely the best studied animal group. As such, the discovery of a new bird species in the 21st century underscores both the actuality of field-based explorations aiming at describing biodiversity, and how such curiosity-driven endeavour is more likely to succeed when coupled with local ecological knowledge, the participation of keen amateur naturalists, and persistence,” they add.

They believe that this “new wave of exploration, carried out by professionals and amateurs alike”, will help rekindle the link to the natural world, which will be essential to help revert the global biodiversity crisis.

Research article:

Melo M, Freitas B, Verbelen P, da Costa SR, Pereira H, Fuchs J, Sangster G, Correia MN, de Lima RF, Crottini A (2022) A new species of scops-owl (Aves, Strigiformes, Strigidae, Otus) from Príncipe Island (Gulf of Guinea, Africa) and novel insights into the systematic affinities within Otus. ZooKeys 1126: 1-54. https://doi.org/10.3897/zookeys.1126.87635

The owls beyond the Andes: Divergence between distant populations suggests new species

They might be looking quite identical, while perched above humanised farmlands and grasslands across several continents, but each of the populations of two owl species, living in the opposite hemispheres, might actually turn out to be yet another kind. This suggestion has been made by Dr. Nelson Colihueque and his team from Universidad de Los Lagos, Chile, based on new genetic divergence analyses of the Common Barn and the Short-eared Owl populations from southern Chile and comparing them with those from other geographic areas. The study is published in the open-access journal ZooKeys.

Although much has been known about the two widespread owl species, the knowledge about them has so far been restricted mainly to aspects such as their diet, conservation status and habitats. On the other hand, their genetic divergence in comparison with populations in distant areas has received little attention. Moreover, their taxonomical status is still based on traditional identification rather than modern methods such as the herein utilised mitochondrial COI sequencing.

Thus, the Chilean research team concluded a significant genetic divergence among the populations of both species from a few distinctive groups. In the case of the Common Barn Owl they compared the new analysis of its South American representatives with already available such data about populations from North America, Northern Europe and Australasia. For the Short-eared Owl, they compared Chilean and Argentinean birds with North American and North Asian.

One of the reasons behind such an evolutionary divergence might be the geographic isolation, experienced by the peripheral South American populations of both owl species. It is a consequence of the Andean Mountains acting as a natural barrier.

“In the case of the Common Barn Owl, the existence of geographic barriers to gene flow among populations on different continents is to be expected, and this in combination with its non-migratory or short-distance migratory behaviour, should contribute to promote the genetic divergence,” further explain the authors.

In conclusion, the researchers call for additional studies to clarify the taxonomic identification of these owl populations.

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Original source:

Colihueque N, Gantz A, Rau JR, Parraguez M (2015) Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence. ZooKeys 534: 135-146. doi: 10.3897/zookeys.534.5953