Abstract
Avian beak deformities, though uncommon in raptors, have considerable consequences for the affected individuals, impacting their feeding, grooming, and social behaviors. This study reports the first known case of a Changeable Hawk-Eagle (Nisaetus cirrhatus) with a unique beak shape observed in Palakkad, Kerala, India, for years. The male had an extra beak-like structure on the top of its mandible and a slight bend in the bottom of its mandible. Despite the deformity, the bird could hunt, eat, and build a nest, showing its adaptability. The deformity, possibly resulting from genetic mutations, environmental factors, or nutritional deficiencies, did not hinder the individual's reproductive success, as indicated by the existence of a presumed offspring. The study underscores the importance of long-term monitoring and interdisciplinary research to understand the causes and implications of beak deformities in wild avian populations. Furthermore, the presence of such anomalies in a top predator emphasizes the potential role of birds as indicators of environmental health. This case contributes to the growing body of research on avian deformities and their ecological impacts, providing valuable insights into the resilience of wildlife facing developmental challenges. Further research into environmental pollutants, genetics, and conservation strategies is essential to mitigate the occurrence of such deformities and their broader ecological consequences.