Sunday, August 29, 2010

Is the Liana Snake a Specialized Bird Nest Predator?

The Liana Snake, Pseustes poecilonotus, is a widespread neotropical snake and probably an important predator on nestling birds. Recently I observed this species emerge from its hiding place under a corrugated tin roof at the Asa Wright Nature Center (AWNC) in Trinidad in the late afternoon. The snake was very cautious and protruded its head from under the roof for about 10 minutes before slowly crawling onto the roof's surface. The AWNC is a popular destination for bird watchers and the roof was adjacent to a large veranda surrounded by bird feeders. There were several Palm Tanager nests within three meters of the snake's hiding place. The Psuestes crawled along the roof and into a small tree where I lost track of it.  Robinson et al. [2005 Ornitologia Neotropical 16:187-195] videotaped 10 instances of nest predation on Panama's Barro Colorado Island, and P. poecilonotus was responsible for eight of the predation events. In one instance the snake ate one nestling and returned to the nest the next day and ate the second bird. Tarwater [2008, The Wilson Bulletin of Ornithology 120(3):620-624] videotaped a P. poecilonotus feeding on a nestling Western Slaty Antshrike, Thamnophilus atrinucha, on Barro Colorado Island. The snake took two minutes to consume the bird. P. poecilonotus is also known to feed on lizards and mammals, but it may specialize in nestling birds when they are available.

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