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When Birds Attack Snakes

by Casey Conrad, SRS Science Communications Intern  • 
jamaican-boa
In every observation made by the scientists, the mobbed boa was a female. Typically larger than their male counterparts, females more easily attract the attention of nearby birds. Photo by Halotron 1, courtesy of Wikimedia Commons.

It’s a bird! It’s a plane! No, it’s … birds attacking a Jamaican boa? In a recent study by USDA Forest Service scientists Richard Schaefer and Craig Rudolph (retired), along with colleagues from Jamaica and Washington, DC, the previously undocumented mobbing of Jamaican boas is brought to scientific light.

The act of multiple birds screeching and surrounding a potential predator, or mobbing, is well documented for many bird species. The defensive response has some contradicting consequences – while it can serve as a protection mechanism and teach youth about potential predators, it can also put the birds at heightened risk of attack from the predator. Never before, however, has mobbing been documented between Jamaican crows (Corvus jamaicensis) and the vulnerable Jamaican boa species (Chilabothrus subflavus), both found only in Jamaica.

Between 2004 and 2013, the researchers recorded four distinct events with unique boas, in addition to another mobbing event by different bird species. In another instance, a boa was strongly suspected of directly preying on a crow’s eggs or nestlings, which led the scientists to better understand the reasons for mobbing by these birds.

The scientists documented the attacks in late spring, late summer, and early fall, leading to the conclusion that mobbing is not exclusive to the crow’s nesting season. In addition, only two or three crows took part in each occurrence, suggesting that predator mobbing was carried out by family units.

The study was published in the Journal of Caribbean Ornithology. For more information, email Richard Schaefer at rick.schaefer@usda.gov.