Anuran Predation by the Large-Tailed Antshrike, Mackenziaena Leachii (Such 1825) (Aves: Passeriformes: Thamnophilidae)
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Herpetology Notes, volume 13: 783-786 (2020) (published online on 30 September 2020) Anuran predation by the Large-tailed Antshrike, Mackenziaena leachii (Such 1825) (Aves: Passeriformes: Thamnophilidae) Daniela A. S. Bôlla1,*, Amanda P. Marcon2, João Vitor P. Andriola3, and Vitor P. Herdy4 Insectivorous Neotropical Passeriformes occasionally (Ridgely et al., 2015). As most Thamnophilidae species, prey upon small vertebrates, although this behaviour is the Large-tailed Antshrike is considered an insectivore not fully understood yet (Poulin et al., 1994; Lopes et al., that feeds mainly on large insects (Santos, 1979; Willis, 2005). One hypothesis is that seasonality influences the 1979; Zimmer and Isler, 2018), found on the ground or density of prey items (Both et al., 2009) – the lower the at lower forest strata (<5 m) (Willis, 1984). Additionally, temperatures, the lower is the number of active insects the predation on frogs (Zimmer and Isler, 2018), lizards (Pinheiro et al., 2002), forcing predators to change their (Zimmer and Isler, 2018), snakes (Zimmer and Isler, feeding behaviour to survive (Tebbich et al., 2004). 2018), birds’ eggs and nestlings (Berlepsch and Ihering, The consumption of uncommon items might relate 1885; Santos, 1979; Zimmer and Isler, 2018) have been either to opportunistic events or to the unavailability described for this species as opportunistic events (Sick, of preferred preys, as a way to fulfil physiological 1997; Zimmer and Isler, 2020). demands (Poulin et al., 2001). The study of avian diets The Hylidae is one of the most predated families of provides an important source of natural history data, anurans, being part of the diet of many taxa, such as both for predators as for their preys (Moojen et al., birds (e.g. Toledo et al., 2011). The genus Boana Gray, 1941; Hempel, 1949; Schubart et al., 1965; Durães and 1825 includes over 90 formally described frog species Marini, 2005). and is among the most diverse hylid genera (Faivovich The Large-tailed Antshrike, Mackenziaena leachii et al., 2005; Frost, 2017). The genus is easily diagnosed (Such, 1825) (Aves: Passeriformes: Thamnophilidae) by its predominantly arboreal habits, the presence of inhabits humid forests, secondary woods and bamboo adhesive toe discs and fingers with intercalary cartilage groves in 500-2100 m of altitude, frequently heard but (Lema and Martins, 2011). hardly seen (Ridgely et al., 2015). Both sexes measure The Emerald-eyed Treefrog Boana crepitans (Wied- about 26 cm beak-tail and are white-dotted along the Neuwied, 1824) occupies several morphoclimatic body (Ridgely et al., 2015). Males are predominantly domains, including anthropic areas in South America black, while females have a brownish-yellow cover (La Marca et al., 2010). It is a medium-sized treefrog (adults measuring 58-70.7 mm snout-vent length [SVL]; Casal and Juncá, 2008) that presents a brownish colouration, ivory venter and flanks, and transverse striations in darker tones (Alves, 2011). The Lesser Treefrog, Dendropsophus minutus (Peters, 1 Mater Natura Instituto de Estudos Ambientais, Bairro Rebouças, Curitiba, Paraná, Brazil. 1872) is another hylid and edible species (Ghizoni-Jr 2 Laboratório de Ecologia de Aves e Mamíferos, Instituto de et al., 2000) preyed upon by a variety of animals, from Biologia, Universidade Federal de Pelotas (UFPel) – Campus invertebrates to vertebrates (Menin et al., 2005; Kopp et Capão do Leão, Capão do Leão, Rio Grande do Sul, Brazil. al., 2006). This treefrog lives in shrubs, trees and water 3 Laboratório Eco Fauna, Universidade Regional Integrada bodies in both forests and green urban areas (Kwet et do Alto Uruguai e das Missões (URI), Campus Erechim, al., 2010; Maneyro et al., 2017). It is most active at night Erechim, Rio Grande do Sul, Brazil. but can be heard in humid and darker areas during rainy 4 Coleção Ornitológica, Museu de Zoologia Newton Baião days (Kwet et al., 2010). Individual adults can measure de Azevedo, Universidade Do Estado De Minas Gerais (UEMG) – Unidade Carangola, Santa Emília, Carangola, up to 28 mm SVL, and their yellowish colour varies to Minas Gerais, Brazil. almost white during the day (Kwet et al., 2010). * Corresponding author. E-mail: [email protected] Even though vertebrate predation events have 784 Daniela A. S. Bôlla et al. been reported for the Large-tailed Antshrike, there beaked on the head and beaten multiple times against is no specific record identifying the prey species nor the ground. Then, the female bird walked away and unequivocal records (e.g. photographs). In this study, we disappeared among the vegetation, carrying the treefrog report on three new prey items belonging to the Hylidae on its beak. Photographs were taken with a Nikon D90 family and consumed by the Large-tailed Antshrike. We camera using 70-130 mm lens, from no more than five also discuss possible motivations for these insectivorous meters of distance. birds to prey upon vertebrates. The second record happened during fall season, on The first record was of an adult female of the Large- 2 May 2014, at 07:54 h., in the Serra da Mantiqueira tailed Antshrike preying upon an individual of Boana mountain chain, within Itamonte municipality (MG), sp. (Fig. 1A) at the touristic trail “Trilha do Encontro” ODF phytophysiognomy, presenting similar climate at Serra do Brigadeiro State Park (municipality of and altitude to that of the first record. This record took Araponga, Minas Gerais (MG) state, southeast Brazil; place in an open area dominated by Poaceae species approximately 1600 m a.s.l [PESB, 2007]), near a as bamboos, in the garden of a country house, aside stream within the Ombrophilous Dense Forest (ODF) the border of a forest fragment. We observed a male phytophysiognomy. The vegetation is dominated by of the Large-tailed Antshrike preying upon an adult Tree ferns (Dicksonia sellowiana Hook.; Cyatheales: Emerald-eyed Treefrog (Fig. 1B). The bird appeared Dicksoniaceae), but is also composed by some emergent after birdwatchers played a playback call, leaving the individuals of Pau-novo (Vochysia magnifica Warm.; forest and soon capturing the treefrog on the grass. After Myrtales: Vochysiaceae). The event took place on 9 capturing, the bird dismembered the frog, consuming it September 2013, about 07:30 h, during winter and the right away in the capture site. Photographs were taken regional dry season, on which the average temperature with a Nikon D300s using 150-500mm Sigma lens, is of 18 ºC and the minimum reaches less than 0 ºC in the from about 10 meters of distance. highest areas of the Park. We observed the anuran being Figure 1. Individuals of the Large-tailed Antshrike (Mackenziaena leachii) preying on hylids. A: Female preying upon a Boana sp. (photo: Herdy, VP); B: Female preying upon a Lesser Treefrog (Dendropsophus minutus) (photo: Andriola, JVP); C and D: Male preying upon an Emerald-eyed Treefrog (Boana crepitans) (photo: Carvalho, H). Anuran predation by the Large-tailed Antshrike 785 The third record involved a female Large-tailed winter, when temperatures are relatively higher in Antshrike feeding on an adult Lesser Treefrog (Fig. comparison to the core-winter, possibly allowing for a 1C, D). The observation was made on 2 July 2018, at higher insect availability (Danks, 1978). This might also 09:30 h, at the Cascata do Avencal Park (municipality of suggest an occasional preference for small vertebrates, Urubici, Santa Catarina state, southern Brazil), during such as anurans, by the Large-tailed Antshrike (Sick, winter (average temperature around 13.4 °C [INMET, 1997; Zimmer and Isler, 2020). 2018]). The bird was perched carrying a Lesser Treefrog Birds of the insectivorous guild, as most on its beak in a clump of Mountain Bamboo (Chusquea Thamnophilidae species (Winkler et al., 2020), seem mimosa McClure & Smith; Poales: Poaceae), on the to have adapted to prey on anurans in understories of verge of a country road. The predator beaked the anuran tropical forests, as the long and narrow beaks of these and partially ingested it while moving between the birds might have facilitated the capture of such preys branches, then disappearing among the vegetation and (Poulin et al., 2001). However, small vertebrates, such not being seen again. Photographs were taken with a as frogs and lizards, composed only 0.5% of the stomach Canon Eos Rebel T5i camera using Sigma 150-500 mm content of birds belonging to the Thamnophilidae lens, from about 10 meters of distance. family (Lopes et al., 2005). Therefore, the opportunistic Some of the reasons for vertebrate ingestion by consumption of small vertebrates by insectivorous primarily insectivorous birds possibly include the birds should be better analysed, as the frequency similarities between invertebrate and small sized may be higher than previously described. We suggest vertebrates, whose length and weight are equivalent further studies on the diet of insectivorous birds to be or even smaller than the invertebrates that normally developed, mainly through stomach content analyses, to compose the diet of these birds (Lopes et al., 2005). As better assess a possible seasonality of their diet. the Large-tailed Antshrike is hardly seen in the wild due to its cryptic habits, data about its diet composition is Acknowledgements. We are much thankful to Heraldo de arduous to acquire. Although it is known that its diet Carvalho for his enthusiasm in contributing with this manuscript; includes a variety of large insects and can include non- to Luciana Frazão for important comments on the first version of this manuscript; to Ana Paula Caron and Tomaz Melo for providing specified small vertebrates (Sick, 1997; Del Hoyo et al., us many references access; and to the editor Gonçalo M. Rosa and 2003), our study is the first one to provide photographic the three anonymous reviewers to their important suggestions. We records with the intent of elucidating part of the bird’s also thank the Conselho Nacional de Desenvolvimento Científico diet.