Snake predators of bird eggs: a review and bibliography

Abstract

. Snakes are frequent predators of bird nests and therefore potentially have an important impact on bird population dynamics. However, while many species are known to consume nestlings and chicks, few species have been recorded consuming bird eggs. To effectively quantify the effects of bird egg predation by snakes on bird demographics, a key first step is to identify which snake species consume bird eggs. Unfortunately, detailed information on the dietary habits of most snakes is scarce and feeding records are poorly cataloged, making it difficult to ascertain which species do and do not eat bird eggs. We reviewed the literature and online community science reports to compile a global list of confirmed snake predators of bird eggs. In total, we gathered 471 feeding records of 123 snake taxa consuming the eggs of at least 210 bird species from 238 individual data sources. Geographical locations of records disproportionately represented well-sampled regions, and we infer that many snake species not included on our list also consume bird eggs. However, we found that oophagous snakes tend to be long (mean maximum length = 2057 mm) and mostly eat eggs that are small in diameter (mean egg diameter = 24 mm), suggesting that relative prey bulk is an important constraint of these interactions. Therefore, we expect that other snakes that eat birds are likely to mostly include congeneric and ecologically similar species to those reflected in our review. By knowing which snakes consume bird eggs, future research can consider species- and site-specific hypotheses when investigating the ecological effects of bird egg predation by snakes. Those results can also inform conservation practitioners on the causes and consequences of variation in nest success that may aid in decision-making when designing conservation management plans. de la presa es una restricción importante de estas interacciones. Por lo tanto, esperamos que otras especies que comen aves, muy probablemente incluyen especies congenéres o ecológicamente similares a las incluidas en nuestra revisión. Conociendo cuales especies consumen huevos de aves, las estudios futuros pueden considerar hipótesis especificas al sitio y a la especie al investigar los efectos ecológicos de la depredación de huevos de aves por serpientes. Esos resultados pueden también informar a conservacionistas sobre las causas y consecuencias de la variación en el éxito de los nidos, lo cual puede ayudar en la toma de decisiones durante el diseño de planes de manejo para conservación.