Weather-induced mass deaths of the Common House Swift <i>Apus affinis</i> in Thengumarahada Village of the Nilgiris, southern India

Abstract

Weather influences all living organisms, especially wild animals. In the case of birds, inclement weather conditions may affect them during migration and feeding that could cause mass mortality in the same species or many related species. This paper describes an incidence of mass deaths of the Common House Swift Apus affinis at Thengumarahada Village of Nilgiris, Tamil Nadu, southern India during February 2008. The samples of the dead birds were sent for toxicological and bacteriological examination at Southern Regional Disease Diagnostic Laboratory, Bangalore. Spot post mortems were also conducted by forest veterinarians. Results of the diagnostic analysis revealed that mass mortality might be due to extreme weather conditions leading to acute dehydration, shock and death. The postmortem reports say that the crop and the gastro intestinal tract (GI) were found empty in all the cases, suggesting starvation. We thus conclude that unseasonal heavy rains and non availability of food could have led to hypothermia and starvation of birds over a long period resulting in mass mortality.