Predation of a Northern Goshawk nestling by a Japanese Rat Snake recorded in a monitoring video

Abstract

We monitored a nest of Northern Goshawk Accipiter gentilis to investigate the cause of continuous nestling loss in an isolated forest patch of Ichinoya Forest in Nagareyama City, Chiba Prefecture, eastern Japan. Using a closed-circuit television (CCTV) camera and digital video recording system, to limit potential disturbance to a minimum for the nesting birds, we monitored the nest during the breeding season of 2018. The result revealed that one of the two nestlings that survived in 2018 was predated by a Japanese Rat Snake in the nest during the night of 26 May, 2018. Although the nest tree was safe-guarded against climbing animals such as Masked musangs Paguma larvata (masked palm civet) or Raccoons Procyon lotor using an ironbelt, the snake approached the Goshawk nest using branches of an adjacent Japanese cedar tree. For a better conservation results, in areas where a deft climber such as the Japanese Rat Snake occurs, we recommend to restrict access to nest trees by managing the adjacent vegetation as well as with trunk protection for the nest tree itself.