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Diet of the Spectacled Owl (Pulsatrix perspicillata) in Zapotillo, southwestern Ecuador

Diet of the Spectacled Owl (Pulsatrix perspicillata) in Zapotillo, southwestern Ecuador Revista Brasileira de Ornitologia 26(1): 52–56. SHORT-COMMUNIC ARA TICLE TION March 2018 Diet of the Spectacled Owl (Pulsatrix perspicillata) in Zapotillo, southwestern Ecuador 1,5 1 2 3,4 Adrian Orihuela-Torres , Leonardo Ordóñez-Delgado , Andrés Verdezoto-Celi & Jorge Brito Departamento de Ciencias Biológicas, Universidad Técnica Particular de Loja, 11-01-608, Loja, Ecuador. Programa ProCamBio, Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, Quito, Ecuador. Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, 17-01-2759, Quito, Ecuador. Instituto Nacional de Biodiversidad. Calle Rumipamba 341 & Av. de los Shyris, 17-07-8976, Quito, Ecuador. Corresponding author: adrian.orihuela89@gmail.com Received on 11 September 2017. Accepted on 20 February 2018. ABSTRACT: We describe the diet of the Spectacled Owl (Pulsatrix perspicillata) based on the collection and analysis of pellets between 20 to 24 December 2016, from a reproductive territory located in Zapotillo, southwestern Ecuador. Mammals were the main food source of the species, accounting for 80% of the identified prey items and 94% of the biomass. Other taxonomic groups, such as amphibians, reptiles and crabs were also identified. Based on our results and t he existing observations, P. perspicillata consumed a big amount of arboreal prey or those that are located at medium height within the forest. This may be due to their hunting habits, the abundance of available prey or a combination of both. Our observation is the first to document the diet of the subspecies P. perspiciliata chapmani, and increases scarce knowledge about the trophic ecology of this species. KEY-WORDS: owls, pellets, prey, trophic ecology, tropical dry forest. One of the most important natural history observations (Latham, 1790) occupies the east of the mountain range to understand the ecology of a species is the knowledge (McMullan & Navarrete 2017). This species inhabits the of its diet, especially the taxonomy of the ingested prey dense rainforest, savanna forests, and tropical dry forest, (Pardiñas & Cirignoli 2002, Cadena-Ortiz et al. 2011). as well as areas with scattered trees, coffee plantations, and Knowing the diet of a species helps to determine, among forest galleries (Holt et al. 2017). These authors suggest other aspects, its intra and interspecific re lationships that their populations are numerous, but there is scarce (Marti et al. 1993). Nevertheless, study of the trophic information on their abundance, population ecology, and ecology of birds faces methodological limitations, behavior. The Spectacled Owl is a species with nocturnal such as the difficulty in identifying the consumed prey activity, although it can occasionally be found on cloudy (Rosenberg & Cooper 1990) and in nocturnal species, days, where it usually rests on leafy trees at banks of their stealth behavior and difficulty of detection, further streams or near bodies of water, at medium height with complicate this type of research (Karr et al. 1990). dense foliage (König & Weick 2008). The level of knowledge about owls (Strigidae) in the Knowledge about the diet of P. perspicillata is Neotropics and even more so in Ecuador remains low mentioned in some field guides (e.g., Stiles & Skutch (Enríquez et al. 2006, Freile et al. 2012, 2017), although 1989, Sick 1993, König & Weick 2008), on the there is information about their distribution and habitat, online database (Holt et al. 2017), and report data of information on the ecological aspects such as behavior prey published in Panama (Voirin et al. 2009), Brazil and trophic niche are deficient (Cadena-Ortiz et al. (Carvalho et al. 2011), and Ecuador (Cadena-Ortiz et al. 2013). 2013, Daza et al. 2017). There is a single detailed study Pulsatrix perspicillata (Latham, 1790) is distributed based on pellets of the Mexican subspecies P. perspicillata from southern Mexico and Central America, to northern saturata (Silva et al. 1997), but information is lacking for Argentina (König & Weick 2008). In Ecuador it is the rest of its distribution. However, the subspecies of our distributed in the lowlands to the east and west of the study, P. perspicillata chapmani, is distributed throughout Andes, primarily under the 1000 m a.s.l. (Ridgely & the Caribbean from Costa Rica, eastern Panama to Greenfield 2001, Freile et al. 2017). With two subspecies, Colombia, western Ecuador and northwestern Peru (Holt Pulsatrix perspicillata chapmani (Griscom, 1932) occupies et al. 2017). This subespcies lacks detailed studies and west of the Andes, and Pulsatrix perspicillata perspicillata only occurrence records are available (Voirin et al. 2009, Revista Brasileira de Ornitologia 26(1): 2018 Diet of Spectacled Owl in Ecuador Orihuela-Torres et al. Cadena-Ortiz et al. 2013). belonged and later classified at the species level. The In this study, we present information on the diet minimum number of individuals consumed (MNI), was of P. p. chapmani in southwestern Ecuador, based on the determined by counting homologous mandibles and analysis of pellets in a reproductive territory. The purpose discarding the other skeletal remains to avoid recounting of this study was to identify its main prey in pellets in the (Manning & Jones-Jr. 1990), except for Hypolobocera tropical dry forest and thus, widen the knowledge about aequatorialis (Ortmann, 1897) (Decapoda) which was its diet. This is the second detailed study on the trophic identified by carapace remains. To calculate the biomass, ecology of this species and the first of the subspecies P. p. the average mass of the species consumed was multiplied chapmani. by the MNI of the species (Herrera & Jaksic 1980). The We collected pellets from a breeding territory different food components were identified using available of P. p. chapmani located in Zapotillo, southwest of guides (Brito et al. 2016, Torres-Carvajal et al. 2016, Ron o o Ecuador (4 07'S; 80 20'W, 481 m a.s.l.), between 20 et al. 2017) and comparisons were made with reference to 24 December 2016, corresponding to the dry season material deposited in the Museum of the Escuela (Maldonado 2002). The nest of a family, composed by Politécnica Nacional (MEPN). two adults and one fledgling (Fig. 1A), was located in a The nine pellets samples were of t he following sizes: Ficus sp. tree, about 4.5 m height in an area with steep length (mean = 44 mm, range = 34 – 59 mm), width slopes and a few meters from a ravine with permanent (mean = 21 mm, range = 13 – 33 mm), mass (mean = water. The type of forest corresponds to dry semi- 4.3 g, range = 2.4 – 8.5 g). There were 15 prey items deciduous forest (Cueva & Chalán 2010). The forest is belonging to four taxonomic classes: Mammalia (3 sp.), patchy with discontinuous clearings, natural or induced, Reptilia (1 sp.), Amphibia (1 sp.) and Malacostraca and the presence of isolated trees. Characteristic species (1 sp.), (Table 1). The body mass of prey varied from of this type of vegetation are Ceiba (Ceiba trichistandra Stenocercus puyango Torres-Carvajal, 2005 (Reptilia) (13 (A. Gray) Bakh.), Guayacan (Tabebuia chrysantha G. g) to Proechimys decumanus Thomas, 1899 (Mammalia) Nicholson), Laurel (Cordia macrantha Chodat), and (285 g). Pretino (Cavanillesia platanifolia (Bonpl.) Kunth), among Mammals were recorded in 100% of the dissected others (Fig. 1B) (Cueva & Chalán 2010). pellets and were the main prey group, both in the The analysis of the pellets was performed in the minimum number of individuals consumed (80%) laboratory, where we measured the length and width and in biomass (93.6%) (Fig. 2). The consumption of of each pellets with a Stainless Hardened digital caliper amphibians, reptiles, and crustaceans was similar. The (precision ± 0.01 mm), and dry mass using a Sartorius most consumed species was the rodent Rhipidomys LA-230P precision balance. We analyzed the pellets and leucodactylus (Tschudi, 1845) and the marsupial Marmosa separated the elements according to their identification simonsi Thomas, 1899, with six and five individuals and quantification (Marti et al. 2007). respectively (Table 1). For biomass, species that The analyzed material in pellets was separated contributed most was R. leucodactylus with 53.6%. The according to the taxonomic groups to which they absence of birds and invertebrates in their diet is striking, Figure 1. Young (left) of Spectacled Owl Pulsatrix perspicillata chapmani next to an adult (right), in Zapotillo, southwestern Ecuador (A). Typical ecosystem where the study of the diet of the Spectacled Owl was carried out (B). Photo author: A. Orihuela-Torres. Revista Brasileira de Ornitologia 26(1): 2018 Diet of Spectacled Owl in Ecuador Orihuela-Torres et al. except the observation of H. aequatorialis (Decapoda). by our findings, in which mammals contributed almost According to previous information published on the all the biomass (93.6%). One of the most abundant diet of P. perspicillata (Stiles & Skutch 1989, Sick 1993, prey items was M. simonsi (MNI = 33.3%, B = 22%), Silva et al. 1997, König & Weick 2008, Holt et al. 2017), a nocturnal marsupial with arboreal habits (Rossi et al. their main prey are mammals. This is further corroborated 2010, Astúa 2015). This genus, belonging to the family Didelphidae, is very common in the diet of P. perspicillata (Silva et al. 1997, König & Weick 2008, Holt et al. 2017). The other most abundant species was R. leucodactylus, a rodent of nocturnal and arboreal habits (Tribe 2015, Tirira 2017), which contributed with 53.6% in biomass. The only mammalian prey species with primarily terrestrial habits was the Pacific Spiny Rat P. decumanus (Tirira 2017). In Mexico, Silva et al. (1997) showed a greater intake of P. perspicillata for a semi arboreal rat (Tylomys nudicaudus Peters, 1866). It appears that P. perspiciliata Mammalia Amphibia Reptilia Malacostraca hunts preferentially over arboreal prey or prey located Taxonomic group in the middle stratum of the forest (Silva et al. 1997), Figure 2. Minimum number of individuals consumed although it can occasionally hunts terrestrial prey. (MNI%) and biomass consumed (B%) in the diet of Pulsatrix Additional studies will be required to determine if this perspicillata chapmani in a breeding territory of Zapotillo, intake can be attributed to hunting habits, the availability southwestern Ecuador. Table 1. Composition of the diet of Pulsatrix perspicillata chapmani in a breeding territory of Zapotillo, southwestern Ecuador. The mass of each species is shown (Mass, in g), the number of individuals and their percentage (MNI, in %), the total biomass in grams and the percentage (Biomass, in %). Taxa Mass (g) MNI (%) Biomass (%) Mammalia 12 (80) 1487 (93.6) Didelphimorphia Didelphidae Marmosa simonsi 70 5 (33.3) 350 (22.0) Rodentia Cricetidae Rhipidomys leucodactylus 142 6 (40) 852 (53.6) Echyimidae Proechimys decumanus 285 1 (6.7) 285 (18.0) Amphibia 1 (6.7) 14 (0.9) Anura Hylidae Trachycephalus quadrangulum 14 1 (6.7) 14 (0.9) Reptilia 1 (6.7) 13 (0.8) Squamata: Sauria Tropiduridae Stenocercus puyango 13 1 (6.7) 13 (0.8) Malacostraca 1 (6.7) 75 (4.7) Decapoda Pseudothelphusidae Hypolobocera aequatorialis 75 1 (6.7) 75 (4.7) Total 15 1589 Revista Brasileira de Ornitologia 26(1): 2018 % Diet of Spectacled Owl in Ecuador Orihuela-Torres et al. of prey, or a combination of both. Voirin et al. (2009) S.A., for financing field trips. Reed Oja la-Barbour and reported the attack of P. perspicillata on a Bradypus Daniel Rosado collaborated by reviewing the manuscript and writing the English. variegatus Schinz, 1825 (Mammalia) when it descended to the ground to defecate. These attacks are not common in owls, as they usually swallow their whole prey and REFERENCES therefore do not consume prey greater than their own body mass (Marti 1974). However, it evidences that the Astúa D. 2015. Family Didelphidae (oppossums), p. 70–186. In: species effectively exploits every opportunity to get food. Wilson D.E. & Mittermeier R.A. (eds.). Handbook of the mammals The absence of bir ds and insects in our study may be of the world, v. 5 (monotremes and marsupials). Barcelona: Lynx biased due to the small sample size. Although, we found a Editions. small proportion of crustaceans, similar to those reported Brito J., Camacho M.A. & Vallejo A.F. 2016. Mamíferos del Ecuador, v. 2016.0. 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Predation on Broad-eared Bat Nyctinomops laticaudatus by the reptiles were represented by S. puyango, a common species Spectacled Owl Pulsatrix perspicillata in southwestern Brazil. in the tropical dry forest of southwestern Ecuador (Yánez- Revista Brasileira de Ornitologia 19: 417–418. Muñoz et al. 2016). A report of the diet of its congener Cueva J. & Chalán L. 2010. Cobertura vegetal y uso actual del suelo Pulsatrix melanota (Tschudi, 1844) in Ecuador showed de la provincia de Loja. Informe Técnico del Departamento de differences in the diet of these species, in this case, only Sistemas de Información Geográfica de Naturaleza & Cultura Internacional. Loja: Gráficas Amazonas. arthropods appeared in the stomach contents (Cadena- Daza J.D., Price L.B., Schalk C.M., Bauer A.M., Borman A.R. Ortiz et al. 2011). However, the sample sizes were small & Peterhans J.K. 2017. 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Clima y vegetación de la región sur del Ecuador, p. 1–28. In: Aguirre Z., Madsen J.M., Cotton E. & Balslev H. (eds.). Botánica Austroecuatoriana. Estudios sobre los recursos To the Department of Biological Sciences - Section of vegetales en las provincias de El Oro, Loja y Zamora – Chinchipe. Ecology and Systematics of the UTPL for institutional Loja: Editorial EDILOJA - Universidad Técnica Particular de support in the development of this work. Equanativa Loja. Revista Brasileira de Ornitologia 26(1): 2018 Diet of Spectacled Owl in Ecuador Orihuela-Torres et al. Manning R.W. & Jones-Jr. J.K. 1990. Remains of small mammals American Museum of Natural History 334: 1–83. recovered from Barn Owl pellets from Crosby county, Texas, Sick H. 1993. Birds in Brazil. New Jersey: Princeton University Press. USA. Texas Journal of Science 42: 311–312. Silva H.G., Pérez-Villafaña M. & Santos-Moreno J.A. 1997. Diet Marti C.D. 1974. Feeding ecology of four sympatric owls. 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Museo de nd including the Galapagos Islands and common mammals, 2 edn. Zoología QCAZ, Pontificia Universidad Católica del Ecuador. Quito: Ratty Ediciones. http://zoologia.puce.edu.ec/Vertebrados/reptiles/reptilesEcuador Pardiñas U.F.J. & Cirignoli S. 2002. Bibliografía comentada sobre los (accessed on 20 July 2017). análisis de egagrópilas de aves rapaces en Argentina. Ornitología Tribe C.J. 2015. Genus Rhipidomys Tshudi, 1845, p. 583–617. In: Neotropical 13: 31–59. Patton J.L., Pardiñas U.F.J. & D'Elía G. (eds.). Mammals of Ridgely R.S. & Greenfield P.J. 2001. The bir ds of Ecuador, v. I: status, South America, v. 2. Rodents. Chicago and London: University of distribution and taxonomy. New York: Cornell University Press. Chicago Press. Ron S.R., Yánez-Muñoz M.H., Merino-Viteri A., Ortiz D.A. & Voirin J.B., Kays R., Lowman M.D. & Wikelski M. 2009. Evidence Nicolalde D.A. 2017. AmphibiaWebEcuador, v. 2017.0. Museo for Three-toed S loth (Bradypus variegatus) predation by Spectacled de Zoología, Pontificia Universidad Católica del Ecuador. http:// Owl (Pulsatrix perspicillata). Edentata 8–10: 15–20. zoologia.puce.edu.ec/Vertebrados/anfibios. (accessed on 20 July Yánez-Muñoz M., Venegas P., Cisneros-Heredia D. & Perez J. 2016. 2017). Stenocercus puyango. The IUCN Red List of Threatened Spe cies Rosenberg K.V. & Cooper R.J. 1990. Approaches to avian diet 2016: e.T50950699A50950702. http://dx.doi.org/10.2305/ analysis. Studies in Avian Biology 13: 80–90. IUCN.UK.2016-1.RLTS.T50950699A50950702.en (accessed Rossi R.V., Voss R.S. & Lunde D.P. 2010. A revision of the didelphid on 23 July 2017). Marsupial genus Marmosa. Part 1. The species in Tate's ‘mexicana’ and ‘mitis’ sections and other closely related forms. Bulletin of the Associate Editor: Cristiano S. Azevedo. 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Diet of the Spectacled Owl (Pulsatrix perspicillata) in Zapotillo, southwestern Ecuador

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Revista Brasileira de Ornitologia 26(1): 52–56. SHORT-COMMUNIC ARA TICLE TION March 2018 Diet of the Spectacled Owl (Pulsatrix perspicillata) in Zapotillo, southwestern Ecuador 1,5 1 2 3,4 Adrian Orihuela-Torres , Leonardo Ordóñez-Delgado , Andrés Verdezoto-Celi & Jorge Brito Departamento de Ciencias Biológicas, Universidad Técnica Particular de Loja, 11-01-608, Loja, Ecuador. Programa ProCamBio, Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, Quito, Ecuador. Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, 17-01-2759, Quito, Ecuador. Instituto Nacional de Biodiversidad. Calle Rumipamba 341 & Av. de los Shyris, 17-07-8976, Quito, Ecuador. Corresponding author: adrian.orihuela89@gmail.com Received on 11 September 2017. Accepted on 20 February 2018. ABSTRACT: We describe the diet of the Spectacled Owl (Pulsatrix perspicillata) based on the collection and analysis of pellets between 20 to 24 December 2016, from a reproductive territory located in Zapotillo, southwestern Ecuador. Mammals were the main food source of the species, accounting for 80% of the identified prey items and 94% of the biomass. Other taxonomic groups, such as amphibians, reptiles and crabs were also identified. Based on our results and t he existing observations, P. perspicillata consumed a big amount of arboreal prey or those that are located at medium height within the forest. This may be due to their hunting habits, the abundance of available prey or a combination of both. Our observation is the first to document the diet of the subspecies P. perspiciliata chapmani, and increases scarce knowledge about the trophic ecology of this species. KEY-WORDS: owls, pellets, prey, trophic ecology, tropical dry forest. One of the most important natural history observations (Latham, 1790) occupies the east of the mountain range to understand the ecology of a species is the knowledge (McMullan & Navarrete 2017). This species inhabits the of its diet, especially the taxonomy of the ingested prey dense rainforest, savanna forests, and tropical dry forest, (Pardiñas & Cirignoli 2002, Cadena-Ortiz et al. 2011). as well as areas with scattered trees, coffee plantations, and Knowing the diet of a species helps to determine, among forest galleries (Holt et al. 2017). These authors suggest other aspects, its intra and interspecific re lationships that their populations are numerous, but there is scarce (Marti et al. 1993). Nevertheless, study of the trophic information on their abundance, population ecology, and ecology of birds faces methodological limitations, behavior. The Spectacled Owl is a species with nocturnal such as the difficulty in identifying the consumed prey activity, although it can occasionally be found on cloudy (Rosenberg & Cooper 1990) and in nocturnal species, days, where it usually rests on leafy trees at banks of their stealth behavior and difficulty of detection, further streams or near bodies of water, at medium height with complicate this type of research (Karr et al. 1990). dense foliage (König & Weick 2008). The level of knowledge about owls (Strigidae) in the Knowledge about the diet of P. perspicillata is Neotropics and even more so in Ecuador remains low mentioned in some field guides (e.g., Stiles & Skutch (Enríquez et al. 2006, Freile et al. 2012, 2017), although 1989, Sick 1993, König & Weick 2008), on the there is information about their distribution and habitat, online database (Holt et al. 2017), and report data of information on the ecological aspects such as behavior prey published in Panama (Voirin et al. 2009), Brazil and trophic niche are deficient (Cadena-Ortiz et al. (Carvalho et al. 2011), and Ecuador (Cadena-Ortiz et al. 2013). 2013, Daza et al. 2017). There is a single detailed study Pulsatrix perspicillata (Latham, 1790) is distributed based on pellets of the Mexican subspecies P. perspicillata from southern Mexico and Central America, to northern saturata (Silva et al. 1997), but information is lacking for Argentina (König & Weick 2008). In Ecuador it is the rest of its distribution. However, the subspecies of our distributed in the lowlands to the east and west of the study, P. perspicillata chapmani, is distributed throughout Andes, primarily under the 1000 m a.s.l. (Ridgely & the Caribbean from Costa Rica, eastern Panama to Greenfield 2001, Freile et al. 2017). With two subspecies, Colombia, western Ecuador and northwestern Peru (Holt Pulsatrix perspicillata chapmani (Griscom, 1932) occupies et al. 2017). This subespcies lacks detailed studies and west of the Andes, and Pulsatrix perspicillata perspicillata only occurrence records are available (Voirin et al. 2009, Revista Brasileira de Ornitologia 26(1): 2018 Diet of Spectacled Owl in Ecuador Orihuela-Torres et al. Cadena-Ortiz et al. 2013). belonged and later classified at the species level. The In this study, we present information on the diet minimum number of individuals consumed (MNI), was of P. p. chapmani in southwestern Ecuador, based on the determined by counting homologous mandibles and analysis of pellets in a reproductive territory. The purpose discarding the other skeletal remains to avoid recounting of this study was to identify its main prey in pellets in the (Manning & Jones-Jr. 1990), except for Hypolobocera tropical dry forest and thus, widen the knowledge about aequatorialis (Ortmann, 1897) (Decapoda) which was its diet. This is the second detailed study on the trophic identified by carapace remains. To calculate the biomass, ecology of this species and the first of the subspecies P. p. the average mass of the species consumed was multiplied chapmani. by the MNI of the species (Herrera & Jaksic 1980). The We collected pellets from a breeding territory different food components were identified using available of P. p. chapmani located in Zapotillo, southwest of guides (Brito et al. 2016, Torres-Carvajal et al. 2016, Ron o o Ecuador (4 07'S; 80 20'W, 481 m a.s.l.), between 20 et al. 2017) and comparisons were made with reference to 24 December 2016, corresponding to the dry season material deposited in the Museum of the Escuela (Maldonado 2002). The nest of a family, composed by Politécnica Nacional (MEPN). two adults and one fledgling (Fig. 1A), was located in a The nine pellets samples were of t he following sizes: Ficus sp. tree, about 4.5 m height in an area with steep length (mean = 44 mm, range = 34 – 59 mm), width slopes and a few meters from a ravine with permanent (mean = 21 mm, range = 13 – 33 mm), mass (mean = water. The type of forest corresponds to dry semi- 4.3 g, range = 2.4 – 8.5 g). There were 15 prey items deciduous forest (Cueva & Chalán 2010). The forest is belonging to four taxonomic classes: Mammalia (3 sp.), patchy with discontinuous clearings, natural or induced, Reptilia (1 sp.), Amphibia (1 sp.) and Malacostraca and the presence of isolated trees. Characteristic species (1 sp.), (Table 1). The body mass of prey varied from of this type of vegetation are Ceiba (Ceiba trichistandra Stenocercus puyango Torres-Carvajal, 2005 (Reptilia) (13 (A. Gray) Bakh.), Guayacan (Tabebuia chrysantha G. g) to Proechimys decumanus Thomas, 1899 (Mammalia) Nicholson), Laurel (Cordia macrantha Chodat), and (285 g). Pretino (Cavanillesia platanifolia (Bonpl.) Kunth), among Mammals were recorded in 100% of the dissected others (Fig. 1B) (Cueva & Chalán 2010). pellets and were the main prey group, both in the The analysis of the pellets was performed in the minimum number of individuals consumed (80%) laboratory, where we measured the length and width and in biomass (93.6%) (Fig. 2). The consumption of of each pellets with a Stainless Hardened digital caliper amphibians, reptiles, and crustaceans was similar. The (precision ± 0.01 mm), and dry mass using a Sartorius most consumed species was the rodent Rhipidomys LA-230P precision balance. We analyzed the pellets and leucodactylus (Tschudi, 1845) and the marsupial Marmosa separated the elements according to their identification simonsi Thomas, 1899, with six and five individuals and quantification (Marti et al. 2007). respectively (Table 1). For biomass, species that The analyzed material in pellets was separated contributed most was R. leucodactylus with 53.6%. The according to the taxonomic groups to which they absence of birds and invertebrates in their diet is striking, Figure 1. Young (left) of Spectacled Owl Pulsatrix perspicillata chapmani next to an adult (right), in Zapotillo, southwestern Ecuador (A). Typical ecosystem where the study of the diet of the Spectacled Owl was carried out (B). Photo author: A. Orihuela-Torres. Revista Brasileira de Ornitologia 26(1): 2018 Diet of Spectacled Owl in Ecuador Orihuela-Torres et al. except the observation of H. aequatorialis (Decapoda). by our findings, in which mammals contributed almost According to previous information published on the all the biomass (93.6%). One of the most abundant diet of P. perspicillata (Stiles & Skutch 1989, Sick 1993, prey items was M. simonsi (MNI = 33.3%, B = 22%), Silva et al. 1997, König & Weick 2008, Holt et al. 2017), a nocturnal marsupial with arboreal habits (Rossi et al. their main prey are mammals. This is further corroborated 2010, Astúa 2015). This genus, belonging to the family Didelphidae, is very common in the diet of P. perspicillata (Silva et al. 1997, König & Weick 2008, Holt et al. 2017). The other most abundant species was R. leucodactylus, a rodent of nocturnal and arboreal habits (Tribe 2015, Tirira 2017), which contributed with 53.6% in biomass. The only mammalian prey species with primarily terrestrial habits was the Pacific Spiny Rat P. decumanus (Tirira 2017). In Mexico, Silva et al. (1997) showed a greater intake of P. perspicillata for a semi arboreal rat (Tylomys nudicaudus Peters, 1866). It appears that P. perspiciliata Mammalia Amphibia Reptilia Malacostraca hunts preferentially over arboreal prey or prey located Taxonomic group in the middle stratum of the forest (Silva et al. 1997), Figure 2. Minimum number of individuals consumed although it can occasionally hunts terrestrial prey. (MNI%) and biomass consumed (B%) in the diet of Pulsatrix Additional studies will be required to determine if this perspicillata chapmani in a breeding territory of Zapotillo, intake can be attributed to hunting habits, the availability southwestern Ecuador. Table 1. Composition of the diet of Pulsatrix perspicillata chapmani in a breeding territory of Zapotillo, southwestern Ecuador. The mass of each species is shown (Mass, in g), the number of individuals and their percentage (MNI, in %), the total biomass in grams and the percentage (Biomass, in %). Taxa Mass (g) MNI (%) Biomass (%) Mammalia 12 (80) 1487 (93.6) Didelphimorphia Didelphidae Marmosa simonsi 70 5 (33.3) 350 (22.0) Rodentia Cricetidae Rhipidomys leucodactylus 142 6 (40) 852 (53.6) Echyimidae Proechimys decumanus 285 1 (6.7) 285 (18.0) Amphibia 1 (6.7) 14 (0.9) Anura Hylidae Trachycephalus quadrangulum 14 1 (6.7) 14 (0.9) Reptilia 1 (6.7) 13 (0.8) Squamata: Sauria Tropiduridae Stenocercus puyango 13 1 (6.7) 13 (0.8) Malacostraca 1 (6.7) 75 (4.7) Decapoda Pseudothelphusidae Hypolobocera aequatorialis 75 1 (6.7) 75 (4.7) Total 15 1589 Revista Brasileira de Ornitologia 26(1): 2018 % Diet of Spectacled Owl in Ecuador Orihuela-Torres et al. of prey, or a combination of both. Voirin et al. (2009) S.A., for financing field trips. 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Journal

Ornithology ResearchSpringer Journals

Published: Mar 1, 2018

Keywords: owls; pellets; prey; trophic ecology; tropical dry forest

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