Interference Competition between Rails and Crakes (Rallidae) during Foraging in the Post-Breeding Season

Authors: MICHAL CIACH

Abstract: In an old riverbed of the Tigris River near the city of Diyarbakir (SE Turkey), observations of foraging Rallidae were made in October 2004. Reciprocal reactions (aggression, mutual foraging) were noted between birds. A total of 20 cases of aggression were observed. The most frequent aggressor was the Water Rail. In an interaction between 2 Spotted Crakes, size difference between the birds was obvious. Three cases of collective foraging were seen: 2 Spotted Crakes, Spotted and Baillon´s Crakes, as well as Little and Baillon´s Crakes. Instances of Crakes and also Moorhens foraging at distances of 3-4 m from each other were common. The above observations show strong aggressive behavior in Water Rails and hint that territorialism in this species during the autumn migration or post-breeding dispersion exists. It is possible that birds of the genus Porzana are also territorial during the autumn migration, although the degree of reciprocal intolerance is moderate.

Keywords: Rallidae, Water Rail, Rallus aquaticus, Crake, Porzana, interaction, aggressive behavior

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