Breeding Biology of Ibisbill (Ibidorhyncha struthersii) in the Kashmir Himalayan Region of India

Abstract. This study aims to describe the breeding biology of Ibisbill (Ibidorhyncha struthersii), a poorly studied wader nesting on the River Sindh in Kashmir Himalayan region of India. A total of 16 nests were monitored during the breeding seasons (late February to late July) of Ibisbill in 2018 and 2019. Nest building was completed in 21-28 days on bare ground by tossing small pebbles into a shallow depression that had no special markings to the human eye (mean pebble size = 4.09 mm ± 1.26 SD x 6.23 ± 3.71 mm, n = 42). Nests measured 28.45 ± 1.75 cm × 18.91 ± 0.99 cm (n = 12). Eggs were laid in the first week of April with clutch size ranging from 2 to 4 eggs. Eggs were 50.58 ± 1.07 mm in length and 36.77 ± 0.85 mm in breadth (n = 5), with egg shape index of 72.23 ± 2.58 (range: 69.23 to 76.42). Incubation lasted 28-32 days, with 3 out of 19 observable eggs successfully hatched (15.79% hatching success). Fledging success was zero due to predation. Defensive behavior was directly observed for 16 nesting pairs during two breeding seasons. A total of 407 defensive incidents were recorded during incubation and chick stage, with both parents engaging in defense together and individually.