Epizootic of beak deformities in wild birds: a review of avian keratin disorder worldwide

GERIK, D; C. VAN HEMERT; B. LAWSON; C. HANDEL; J.F WALTERS; K. BRUST; A. PRINZ; A. VAN LANEN; J. SCHILLACI; S. COTTRELL; C. ANDERSON; GOROSITO, C.A.; CUETO, V.R.; M. ZYLBERBERG

Anchorage

Congreso; XX Alaska Bird Conference; 2023

Anepizootic of debilitating beak deformities in wild birds has beendocumented in recent decades. Avian keratin disorder (AKD) ischaracterized by overgrowth of beak keratin and was first observed inclusters among Black-capped Chickadees (Poecileatricapillus)in Alaska. The prevalence of beak deformities is higher amongBlack-capped Chickadees and American Crows (Corvusbrachyrhynchos)in Alaska than in any other population ever recorded. Reports ofbirds with similar beak deformities have also been documented acrossNorth America, in South America, and in Europe. Wecompiled reports from community-science programs, bird monitoringstudies, and scientific literature to summarize the currentgeographic scope and bird species affected by AKD-like beakdeformities. From 1946 to 2021, >3,300 community-science observersreported 290 species with beak deformities, comprising >4,000birds in Alaska, 1,900 elsewhere in North America, and >1,700 fromoutside of North America. Wealso examined the occurrence of beak deformities in populations ofRed-tailed Hawks (Buteojamaicensis)in the Pacific Northwest, Red-cockaded Woodpeckers (Dryobatesborealis)in North Carolina, and Austral Thrushes (Turdusfalcklandii)in Patagonia. Clinical signs of AKD in Black-capped Chickadees havebeen strongly associated with the occurrence of a novel picornavirus,which has now been detected in multiple species exhibitingmorphologically similar beak deformities.Ourdetailed compilation, including geographic occurrence of individualsand species apparently affected, will help identify research andconservation actions required to evaluate and mitigate impacts ofbeak deformities on wild birds.