Public Release:  Hidden in plain sight: Amazonian bird chick mimics toxic caterpillar to avoid being eaten

To respond to high rates of predation, an Amazonian bird has developed a novel nesting strategy employing Batesian mimicry

University of Chicago Press Journals

IMAGE

IMAGE: The top image shows a cinereous mourner nestling (Laniocera hypopyrra). The bottom shows a large, hairy caterpillar from the area (Megalopyge or Podalia sp.) that matches the nestling's plumage characteristics.... view more

Credit: Top, Santiago David Rivera; bottom, Wendy Valencia

In a study published in the January 2015 issue of The American Naturalist, Gustavo A. Londoño, Duván Garcia, and Manuel Sánchez Martínez report a novel nesting strategy observed in a tropical lowland bird that inhabits an area with very high losses to nest predators.

How can tropical birds cope with the high rates of nest predation that are typical in most tropical habitats? Are there nesting strategies that allow tropical birds to escape predators such as birds, mammals, and snakes that regularly eat eggs and nestlings?

During the fall of 2012, while working on a long-term avian ecological study, the researchers discovered the second nest ever described for the cinereous mourner (Laniocera hypopyrra) at Pantiacolla Lodge in the upper Madre de Dios River in southeastern Peru. They observed that upon hatching, the chicks had downy feathers with long orange barbs with white tips, which was very different from any other nestling they had observed in the area. The peculiar downy feathers attracted their attention, but the nestling behavior provided a more important cue. While researchers were collecting morphological measurements, the nestling started moving its head very slowly from side to side in a way typical of many hairy caterpillars. While working in the area, the investigators found a poisonous caterpillar with similar size and hair coloration as the nestling. Therefore, the researchers suggest that this is an example of Batesian mimicry in which the nestling tricks predators into thinking that it is a toxic, spiny caterpillar rather than a highly edible nestling.

This remarkable adaptation may well have evolved to decrease nest predation probability, increasing nesting success in this species. Examples of Batesian mimicry are very rare in vertebrates.

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Gustavo A. Londoño, Duván A. García, and Manuel A. Sánchez Martínez, "Morphological and Behavioral Evidence of Batesian Mimicry in Nestlings of a Lowland Amazonian Bird." The American Naturalist Vol. 185, No. 1 (January 2015), pp. 135-141. http://www.jstor.org/stable/10.1086/679106

Since its inception in 1867, The American Naturalist has maintained its position as one of the world's premier peer-reviewed publications in ecology, evolution, and behavior research. Its goals are to publish articles that are of broad interest to the readership, pose new and significant problems, introduce novel subjects, develop conceptual unification, and change the way people think. AmNat emphasizes sophisticated methodologies and innovative theoretical syntheses--all in an effort to advance the knowledge of organic evolution and other broad biological principles.

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