There are several birds with nocturnal activity, among them the most popular are owls, however they are little studied. They make up the order Strigiformes, are predatory birds of mostly nocturnal habits (Sick, 2001), however, Johnson (2003) says one-third of owls are active during the day.
They are birds specialized in hunting in low light environments and for this they have several adaptations that differentiate them from the other birds of prey and give them peculiar characteristics (Sick, 2001; Burton, 1984). To better detect your prey, they have large eyes with enlarged cornea, pupil and lens, which guarantee more light entry into the retina but make the eyeball virtually immobile and consequent limited field of vision. To compensate, they have a head that rotates 270º, however the owls use little vision in hunting, it is the sharp perception hearing that draws attention to these birds. They have asymmetric ears and a facial disc that functions as a parabolic, capturing, amplifying the volume of the sound and directing it to the ear, allowing it to accurately locate its prey amid the ambient noises.
Discreet, they are little noticed, even by the prey. They fly silently thanks to their soft plumage that can reduce friction with the air, producing no noise. Because of the nocturnal habit, of the lugubrious voice, of such peculiar abilities and characteristics, in virtually all cultures owls are in some way associated with signs of unhappiness, creatures of darkness, bad luck and death; They are found practically all over the world, in the most diverse habitats, and its relation with man is old and somewhat controversial. Some people believe that owls are evil emissaries, but in other cultures they are symbol of wisdom, luck and prosperity. Unfortunately, most of these superstitions compromise the existence of these birds (Burton, 1994; Sick, 2001; Mikich & Bémils, 2003; ICMBio, 2008, Esclarski et al., 2011).
There are over 250 species of owls worldwide (Strigiformes, Tytonidae and Strigidae families), and according to the Brazilian Committee of Ornithological Registries, in Brazil there are 23 species (CBRO, 2014). Of the 23 species, only Tyto furcata (American Barn Owl)does not belong to the Strigidae, the others are representatives of the genus Aegolius, Asio, Athene, Bubo, Glaucidium, Lophopstrix, Megascops, Pulsatrix and Strix, whose larger species is Bubo virginianus (Great Horned Owl, 45-60 cm) and the smallest Glaucidium minutissimum (Least Pygmy-Owl, 14 cm). Of these, Athene cunicularia (Burrowing Owl) is the only species essentially terrestrial, and seems to have adapted well to the urban environment, as well as Megascops choliba (Tropical Screech-Owl), Asio flammeus (Short-eared Owl) and Tyto furcata (American Barn Owl). According to the existing data, some species have a restricted distribution to the Atlantic Forest, such as Glaucidium minutissimum (Least Pygmy-Owl), Glaucidium mooreorum (Pernambuco Pygmy-Owl), Megascops atricapilla (Black-capped Screech-Owl), Megascops sanctaecatarinae (Long-tufted Screech-Owl), Pulsatrix koeniswaldiana (Tawny-browed Owl) and Strix hylophila (Rusty-barred Owl). While others are restricted in the Amazon, such as Glaucidium hardyi (Amazonian Pygmy-Owl), Lophostrix cristata (Crested Owl), Megascops guatemalae (Vermiculated Screech-Owl), Megascops usta (Austral Screech-Owl) and Megascops watsonii (Tawny-bellied Screech-Owl).
It is believed that with molecular and phylogenetic studies, the number of Brazilian species can increase considerably, since several geographic populations of the species already known, are not well explained. But this can be alarming since we do not know for sure the conservation status of Brazilian species. There is a lack of data on the natural history of owls and lack of studies on distribution and abundance may place some of these birds on the list of endangered species, and possible new species on the verge of extinction (IBAMA, 2003). As an example, we have the species Glaucidium mooreorum (caburé-de-pernambuco) probably extinct, due to its restricted distribution added to the absence of records since its description in 2002. Although they inhabit the most diverse environments, from dense forests to altitude fields, and even adapt to urban centers. Many of these species, from the rare to the most common, suffer from the expansion of deforestation and fragmentation of habitats, with pollution, poisoning and unfortunately, with fortuitous attacks due to popular beliefs and domestic animals (ICMBio, 2008).
One of the great challenges of today is to reconcile environmental conservation with the needs and culture of local populations, who sometimes depend directly on natural resources for their livelihood (Lima et al., 2014). Owls need, more than ever, our watchful eye as a citizen and scientist.
References
SICK, H. Ornitologia Brasileira. 1ª ed. Rio de Janeiro: Editora Nova Fronteira, 2001.
Burton, J. A. 1984. Owls of the world: their evolution, structure and ecology. Revisited Edition. Tanager Books, Dover
MIKICH, S. B. & OLIVEIRA, K. L. 2003. Revisão do Plano de Manejo do Parque Estadual Vila Rica do Espírito Santo. Mater Natura. Curitiba, Instituto de Estudos Ambientais, Ministério do Meio Ambiente e Fundo Nacional do Meio Ambiente, XXI+452p
ICMBio, 2008. Plano de ação nacional para a conservação de aves de rapina / Instituto Chico Mendes de Conservação da Biodiversidade, Coordenação-Geral de Espécies Ameaçadas. – Brasília. 136 p. Série Espécies Ameaçadas, 5. ISBN 978-85-7300-240-9
ESCLARSKI, P.; MENQ, W.; GARUTTI, S.. Corujas: verdades e mitos. uma análise das crendices populares envolvendo as corujas. Anais. VIII EPCC – ENCONTRO INTERNACIONAL DE PRODUÇÃO CIENTÍFICA / CESUMAR – Centro Universitário de Maringá. Editora CESUMAR Maringá, 2011.
CBRO – Comitê Brasileiro de Registros Ornitológicos (2014) Listas das aves do Brasil. Versão 01/01/2014. Disponível em <http://www.cbro.org.br/PDF/avesbrasil_2014jan1.pdf> Acesso em: 23 de Março de 2019.
IBAMA. 2003. Lista de espécies da Fauna Brasileira ameaçadas de Extinção. Instrução Normativa do Ministério do Meio Ambiente
LIMA. L.M. Aves da Mata Atlântica: riqueza, composição, status, endemismos e conservação. (dissertação/mestrados) – Instituto de Biociências da Universidade Estadual de São Paulo, 513p.
– LIMA. L.M. 2014. Aves da Mata Atlântica: riqueza, composição, status, endemismos e
conservação. (dissertação/mestrados) – Instituto de Biociências da Universidade
Estadual de São Paulo, 513p.
– Burton, J. A. 1984. Owls of the world: their evolution, structure and ecology. Revisited Edition. Tanager Books, Dover.
– Johnson, D. (2003) Owls in the Fossil Record. Disponivel em: <https://www.owlpages.com/owls/articles.php?a=17> Acesso em: 23 de Março de 2019.
Asio flammeus – Short-eared Owl
It is a medium-sized owl, common in rural and swampy áreas. Its distribution is wide in the world, occurring in the Americas, Europe and Asia. In Brazil, as in tropical regions, it is sedentary; while northern populations documented migration.
Athene cunicularia – Burrowing Owl
It is a common owl in open areas and widely distributed in the Americas. Its name comes from the habit of building burrows on the ground for laying eggs, digging tunnels up to two meters. In Brazil it is easily found in open fields, pastures, beaches and urban areas.
Bubo virginianus – Great Horned Owl
Its name refers to the tufts of feathers on its head that resemble horns or ears. It is the largest of the species that occur in Brazilian territory and can be found in semi-open areas, with trees spaced across the Americas.
Glaucidium hardyi – Amazonian Pygmy Owl
It is a small owl with distribution restricted to the Amazon region. It is most often heard, because in addition to its small size, it lives just below the forest canopy, amid the bromeliads and vines, so it is hardly seen. Although small, it is a voracious predator of insects and small vertebrates and a fearless defender of its territory.
Glaucidium minutissimum – Least Pygmy Owl
It is one of the smallest owls in the world and the smallest in Brazilian territory. Endemic to the Atlantic Forest, it prefers the canopy and is therefore rarely seen. Although small, it is capable of hunting small vertebrates such as amphibians, lizards and even other birds.
Strix huhula – Black-banded Owl
It is a medium-sized owl, restricted to South America. It is divided into two subspecies whose distribution is apparently linked to the Amazon and Atlantic forests. In Brazil it is a species of unusual occurrence, considered threatened in the region of Atlantic forest, but apparently tolerates environments altered by man.
Lophostrix cristata – Crested Owl
It is a medium-sized owl with two large white crests (tufts) above the eyes, to which its name refers. Inhabitant of the upper layer of humid forests in the tropical region, this owl endemic to the Amazon is characterized by its unmistakable bass vocalization.
Megascops atricapilla– Black-capped Screech Owl
It is very similar to species of the same genus, with variation in the color of plumage and iris, characterized by a dark area on the nape and on the top of the head (black hood). It is distributed in the south of South America, in areas of Atlantic Forest, where its vocalization can be easily confused with that of an amphibian that occurs in the same region.
Megascops choliba – Tropical Screech Owl
It is a owl of wide distribution in South and Central America. In Brazil it occurs in all states and can be found even in an urban environment, where it is common to see it catching insects on lampposts.
Megascops usta – Southern Tawny-bellied Screech Owl
Although there is disagreement between many authors and some still consider the same species, M. usta was separated from M. watsonii by the remarkable variation in vocalization. Restricted to the Amazon region, it is common to find this species inside the forest, inhabiting the lower strata of vegetation. It replaces M. watsonii, being distributed to the south of the Amazon River.
Megascops sanctaecatarinae – Long-tufted Screech Owl
Largest representative of the genus, this species is restricted to southern South America. Its name refers to the place from which its description originates (Santa Catarina State – Brazil). In Brazil, occurs together with M. choliba and M. atricapilla, with which it is very similar, and despite the distinct size, it is only possible to differentiate them safely in the field through vocalization.
Megascops watsonii – Northern Tawny-bellied Screech Owl
Restricted to the Amazon region, its name refers to its area of occurrence, which occurs north of the Amazon River. This river that serves as a geographical barrier in the distribution of several species, among them one of the same genus, Megascops usta, which although very similar, presents significantly different vocalization.
Asio clamator – Striped Owl
It is a medium-sized species, characterized by the black streaks of its plumage, prominent tufts on the head that resemble ears and its acute vocalization compared by many to the meow of a cat. This species is found from southern Mexico to Central and South America, in open areas and regions of sparse vegetation. In Brazil, it is common in coastal regions, natural fields, cerrado, caatinga to areas modified by man (urban and rural).
Aegolius harrissi – Buff-fronted Owl
This species is characterized by the beauty of its plumage and discretion in its behavior, which makes it one of the most difficult to find. Little is known about its reproductive biology, behavior and there is no consensus on its distribution, since its records are punctual, isolated and wide in South American territory. In Brazil, its records are concentrated in the south, southeast and northeast of the country
Asio stygius – Stygian Owl
Characterized by tufts of feathers that resemble horns on its head, this owl is distributed in the Americas, and it can eventually be seen in urban wooded areas. They are extremely territorial and tend to feed on small vertebrates, especially birds and bats. This Owl characteristics such as long ears tufts, dark coloration and particularly the brilliant red reflection of the eyes when illuminated by lamps have been associated with the Devil. Its scientific name “stygius” refers to hell and its vernacular name in Brazil is “devil’s owl”.
Pulsatrix perspicillata – Spectacled Owl
One of the largest species that occur in Brazilian territory, this owl is not the most sociable and is heard more than seen. Considered threatened in some regions of the country, it occurs more frequently in areas of dense tropical forest, with large and mature trees. Their diet includes small vertebrates such as bats and birds, including other species of owls.
Glaucidium brasilianum – Ferruginous Pygmy Owl
Small owl of distribution restricted to South America, very common and widely occurring in Brazilian territory. Very aggressive despite its small size, it feeds mainly on birds and its prey can be up to 4 times larger than its size. Uses medium vegetation extracts and can easily be seen in man-modified areas.
Pulstrix koeniswaldiana – Tawny-browed Owl
Species restricted to the Atlantic Forest and very similar to other representatives of the genus, distinguishable mainly by the dark iris and the vocalization, slightly smaller size and brown plumage in relation to the pure white that P. perspicillata presents on its face. The two species occur together in some areas of higher altitude, however this owl seems to tolerate a higher level of habitat change.
Strix virgata – Mottled Owl
Medium-sized owl that occurs from Mexico, throughout Central and South America. It can occupy a wide variety of habitats, from dense forests to open and even urban areas. It has seven recognized subspecies, of which two occur in Brazil: superciliaris restricted to the Amazon and borellians from southern Bahia to Rio Grande do Sul.
Strix hylophila – Rusty-Barred Owl
Medium-sized owl restricted to the Atlantic Forest, is a rare and poorly studied species. Its vernacular name is due to the characteristics of its plumage. In Brazil it is found in forests of different degrees of degradation, from primary to anthropogenic environments. It is considered a species threatened by the degradation of the Atlantic Forest, which drastically reduces its area of occurrence.
Tyto furcata – Amrican Barn Owl
This species is characterized by its strong vocalization and is among the most useful birds in the world, when it comes to man’s economy. This is due to her ability to adapt to anthropogenic environments and her eating habits, which leads her to consume many rodents, especially in the vicinity of human habitation. Thus contributing to the control of animal populations considered urban pests. Until recently it was considered T. alba, in 2014 it became recognized as T. furcata those occurring in the Americas and T. alba those in the old world.