Notas científicas

 

Mexican jay (Aphelocoma wollweberi) predation on baird's rat snake (Pantherophls balrdi) in Nuevo León, Mexico

 

Chara pecho gris (Aphelocoma wollweberi) predación sobre la culebra ratonera de bosque (Pantherophls balrdi) en Nuevo León, México

 

Jorge A. Contreras-Lozano^1* and Óscar Ballesteros-Medrano²

 

¹ Laboratorio de Herpetología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apartado Postal 425, San Nicolás de los Garza, Nuevo León, México. CP 66450. <jorgeacl.84@gmail.com>

² Laboratorio de Ornitología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apartado Postal 425, San Nicolás de los Garza, Nuevo León, México. CP 66450.

 

Recibido: 20/02/2015.
Aceptado: 15/08/2015.

 

Resumen

Se observó un adulto de chara pecho gris (Aphelocoma wollweberi) sosteniendo y picoteando un juvenil de la culebra ratonera de bosque (Pantherophis bairdi) en un aparente intento de depredación, la cual es una interacción de estas especies no reportado. El suceso ocurrió en el Parque Nacional Cumbres de Monterrey, en la localidad de Chipinque, San Pedro Garza García, Nuevo León, México.

 

The Mexican Jay (Aphelocoma wollweberi) inhabits mountains with pine-oak woodland (Dunn & Alderfer 2008) and forages preferentially on acorns and pinyon nuts in fall and winter (McCormack et al. 2008), and beetles, grasshoppers, crickets, and other arthropods, small lizards, snakes, and frogs, throughout the year. Stomach contents analyses have documented the remains of carabid, elater, bupestrid, and other beetles, and bark-clinging moths (Smith 1908, Westcott 1969), and reptiles (Contreras-Balderas & Treviño-Saldaña 1987). These jays also feed on eggs of their own species (Brown 1963, Trail et al. 1981) and are suspected of eating eggs and nestlings of other birds (Gross 1949, Brandt 1951), although they are rarely observed doing so. In snowy winters they may attempt to take small birds (Roth 1971) and mice (Brandt 1951). The Baird's Rat Snake (Pantherophis bairdi) is distributed throughout the Sierra Madre Oriental in the states of Coahuila, Nuevo Leon, and Tamaulipas in northeast Mexico and has limited distribution in west-central Texas (Werler & Dixon 2000).

On 14 August 2011, we observed a Mexican Jay holding a dead juvenile Baird's Rat Snake (Pantherophis bairdi) in its bill (Fig. 1). The observation occurred at 0920 hours on a cloudy day (24 °C) in a pine-oak forest at Parque Nacional Cumbres de Monterrey in the locality known as Chipinque in San Pedro Garza Garcia, Nuevo Leon, Mexico (25° 36' 26" N, 100° 21' 14" W, WGS84, 1280m). During the event, the jay stood on the snake (total length = 299 mm) and pecked its head. After doing so for a few minutes, the jay, apparently fearful of our presence, dropped the snake, watched it for a short period, and then flew away. Our observation is the first to reveal predatory interaction between these two taxa. Interestingly, their roles might well have been reversed, depending on the size of the snake, birds being frequent prey of rat snakes throughout the northern hemisphere.

In the photograph (Fig. 1), it looks as though the jay is holding the snake down with its foot, grasping the neck with its bill, and pulling upwards just as raptors do.

Predation of Mexican Jays upon snakes was previously documented by Contreras-Balderas and Treviño-Saldaña (1987) and by McCormack and Brown (2008). A. J. Contreras-Balderas (pers. comm.) has observed predation of various unidentified snakes in Cerro El Potosi, Nuevo Leon, Mexico.

 

ACKNOWLEDGEMENTS

We thank to Ignacio Rodriguez for his photo, and M.E. Marshall, and Dr. R. Bezy for their comments and corrections of an early draft of this note, also the two anonymous reviewers contributing with interesting comments.

 

LITERATURE CITED

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Brandt, H. 1951. Arizona and its bird life. The Bird Research Foundation, Cleveland. 723 pp.         [ Links ]

Contreras-Balderas, A. J. & Treviño-Saldaña, C. H. 1987. Notas sobre predación de aves en reptiles. Southwestern Naturalist, 32: 505-527.         [ Links ]

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Westcott, P. W. 1969. Relationships among three species of jays wintering in southeastern Arizona. Condor, 71: 353-359.         [ Links ]