The Puerto Rican owl (''Gymnasio nudipes'') or ''múcaro común'' ( Spanish via Taino), formerly known as the Puerto Rican screech owl, is a mid-sized " true owl" in the subfamily Striginae. It is endemic to the island of

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...

, though it also formerly inhabited the

Virgin Islands The Virgin Islands ( es, Islas Vírgenes) are an archipelago in the Caribbean Sea. They are geologically and biogeographically the easternmost part of the Greater Antilles, the northern islands belonging to the Puerto Rico Trench and St. Croix ...

.HBW and BirdLife International (2020) ''Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world'' Version 5. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v5_Dec20.zip xls zipped 1 MBretrieved 27 May 2021Goodson, C. (2021). Puerto Rican Owl (''Gymnasio nudipes''), version 1.1. In Birds of the World (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.prsowl.01.1 retrieved March 9, 2022

Taxonomy and systematics

The Puerto Rican owl was formally described in 1800 by the French zoologist

François Marie Daudin François Marie Daudin (; 29 August 1776 in Paris – 30 November 1803 in Paris) was a French zoologist. With legs paralyzed by childhood disease, he studied physics and natural history, but ended up being devoted to the latter. Daudin wrote ' ( ...

from specimens collected in Puerto Rico. He coined the

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''Strix nudipes''. The species was subsequently placed either in the genus ''

Otus Otus may refer to: * Otus (education), a K-12 educational technology company * HMS ''Otus'', two ships in the Royal Navy * ''Otus'' (bird), genus of owls * Otus (mythology), giant in Greek mythology, brother of Ephialtes, one of Aloadae * Otus o ...

'' with the scops owls or in ''

Megascops Screech owls are typical owls (Strigidae) belonging to the genus ''Megascops'' with 23 living species. For most of the 20th century, this genus was merged with the Old World scops owls in ''Otus'', but nowadays it is again considered separat ...

'' with the screech owls. It is now the only species assigned to the genus ''Gymnasio'' that was introduced in 1854 specifically for the Puerto Rican owl by

Charles Lucien Bonaparte Charles Lucien Jules Laurent Bonaparte, 2nd Prince of Canino and Musignano (24 May 1803 – 29 July 1857), was a French naturalist and ornithologist. Lucien and his wife had twelve children, including Cardinal Lucien Bonaparte. Life and career ...

. The genus name combines the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''gumnos'' meaning "bare" or "naked" with the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''asio'', a type of eared owl. The specific epithet ''nudipes'' is Latin meaning "bare-footed". A species endemic to the

was described in 1860 by

George Newbold Lawrence George Newbold Lawrence (October 20, 1806 – January 17, 1895) was an American businessman and amateur ornithologist. Early life Lawrence was born in the city of New York on October 20, 1806. From his youth, Lawrence was a lover of birds and s ...

under the binomial ''Gymnoglaux newtoni''. This is treated as a subspecies of the Puerto Rican owl (''Gymnasio nudipes newtoni''), but its identity as a separate subspecies has been questioned because it is based on minor differences in plumage. The taxon is probably extinct, as surveys of the Virgin Islands conducted since 1995 have failed to detect any Puerto Rican owls. A

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study of the owls published in 2019 found that the Puerto Rican owl is a sister species to the

flammulated owl The flammulated owl (''Psiloscops flammeolus'') is a small migratory North American owl in the family Strigidae. It is the only species placed in the genus ''Psiloscops''. Taxonomy The flammulated owl was formally described in 1852 by the Germ ...

(''Psiloscops flammeolus''), a migratory species in North America.

Description

The Puerto Rican owl is long with a wingspan of . It weighs , with females being slightly heavier than males. It has a rounded head with no "ear" tufts. It has three color morphs; the brown one predominates, the rufous one is fairly common, and the gray one is rare. The brown morph has brown upperparts with irregular paler brown bars and

vermiculation Vermiculation is a surface pattern of dense but irregular lines, so called from the Latin ''vermiculus'' meaning "little worm" because the shapes resemble worms, worm-casts, or worm tracks in mud or wet sand. The word may be used in a number of ...

. The tail is also brown with paler vermiculation. The wing

coverts A covert feather or tectrix on a bird is one of a set of feathers, called coverts (or ''tectrices''), which, as the name implies, cover other feathers. The coverts help to smooth airflow over the wings and tail. Ear coverts The ear coverts are sm ...

have some whitish spots. Its

facial disc In ornithology, the facial disc is the concave collection of feathers on the face of some birds—most notably owls—surrounding the eyes. The concavity of the facial disc forms a circular paraboloid that collects sound waves and directs those ...

s have narrow light and dark brown bars; the

supercilium The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head.Dunn and Alderfer (2006), p. 10 Also ...

and lores are white. The underparts are mostly white with much brown or dusky streaking, barring, and vermiculation. The belly and undertail coverts are usually plain white. The legs are not feathered, which is unusual in owls, and led to another former common name, the Puerto Rican bare-legged owl. The eye is brown, the bill greenish yellow, and the legs and feet pale brown to grayish yellow. The rufous morph replaces the brown with pale reddish brown or ochre buff. Putative subspecies ''G. n. newtoni'' has somewhat paler upperparts and less heavily streaked underparts than the nominate.

Distribution and habitat

The Puerto Rican owl is found throughout the main island of Puerto Rico. The putative subspecies ''G. n. newtoni'' certainly occurred on

St. Croix Saint Croix; nl, Sint-Kruis; french: link=no, Sainte-Croix; Danish and no, Sankt Croix, Taino: ''Ay Ay'' ( ) is an island in the Caribbean Sea, and a county and constituent district of the United States Virgin Islands (USVI), an unincorpo ...

, St. John, and St. Thomas in the Virgin Islands but has not been positively recorded there since the mid 1800s. It possibly occurred on other Virgin Islands and on Vieques and Culebra, but no documentation supports those assertions. On Puerto Rico its primary natural habitat is humid lowland forest but it also occurs in dry forest and urban areas. "Any small territory with available nest cavities is ideal for this species."

Behavior

Movement

The Puerto Rican owl is resident throughout its range.

Feeding

The Puerto Rican owl is a nocturnal hunter. Its primary prey is large

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

s such as

cockroach Cockroaches (or roaches) are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as ...

es,

grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grasshopp ...

s, and

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

s. It also regularly eats small vertebrates such as frogs, lizards,

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

s, and birds.

Breeding

The Puerto Rican owl's breeding season spans from April to June. It nests in cavities in trees and lays a clutch of up to three white eggs. Little else is known about its breeding

phenology Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonality, seasonal and interannual variations in climate, as well as environmental factor, habitat factors (such as elevation). Examples includ ...

Vocalization

The Puerto Rican owl's territorial song is "a short, relatively deep, somewhat guttural, toad-like quavering trill...''rrurrrrrrr''." It also makes "a soft cackling ''gu-gu'' and "a loud ''coo-coo''"; the latter call provides the local colloquial name "cuckoo bird".

Status

The

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has assessed the Puerto Rican owl as being of Least Concern. Though it has a relatively small range, its population exceeds 10,000 mature individuals and is believed to be stable. No specific threats have been identified. Its disappearance from the Virgin Islands is thought to have happened because the native forests there were mostly cleared by the end of the nineteenth century.

Gallery

File:Megascops nudipes-Mucarito-Screech Owl of Puerto Rico Second Bird.jpeg, An adult at the western municipality of Aguada File:Megascops nudipes Owlet Mucarito-Screech Owl of Puerto Rico.jpeg, An owlet