Observations on behaviour and foraging of the Ibisbill Ibidorhyncha struthersii in Nepal

In March and April 1984, I studied the territorial, courtship and foraging behaviour of Ibisbills Ibidorhyncha struthersii, mainly on Langtang Khola in Nepal. On their river-bed breeding grounds, Ibisbills were territorial, rival birds meeting on shingle banks and performing prolonged circling displays. Aquatic invertebrates, especially stoneflies, mayflies and caddisflies, were the main prey, but fish and riparian invertebrates were taken also. When the water temperature was below 5oC, invertebrates were inactive and hidden beneath submerged stones, where the birds probed for them. When the water temperature was above 5oC, many invertebrates drifted in the water and Ibisbills switched to pecking at them from preferred feeding stations. Riparian foraging involved probing beneath stones on shingle banks and probing into soil. Foraging responses to changes in prey behaviour were similar to those of the Black Stilt Himantopus novaezealandiae on New Zealand river-beds.