Dangerous traps: Anhingas mistake anthropogenic debris for prey fish at an urban site in South-eastern Brazil

Abstract

Impacts of anthropogenic inedible debris on seabirds have been well documented, but on inland waterbirds this kind of pollution remains poorly recorded. Herein we report 21 instances of inedible objects stuck in the bill of Anhinga (Anhinga anhinga), a fish-eating waterbird which has the cutting edges of the mandible serrated. Disturbance and harm by pieces of plastic, rope, and cotton stuck in the bill were recorded. Debris caused drag and prevented the birds from fishing. Birds with small pieces of material stuck on their bills were still able to fish, but their hunting success decreased. When the debris was large and stuck on the bill for long, the birds possibly starved and some of them died. The time spent to clean up the bill was related to the type of material, ranging from 1 to 17 days. Our records illustrate the deleterious effect that anthropogenic debris has on the life of a Neotropical aquatic inland bird.