Environmental variables associated with population patterns of the Kagu Rhynochetos jubatus of New Caledonia

The first comprehensive survey of the threatened Kagu Rhynochetos jubatus of New Caledonia based on 177 different listening areas outside the Rivière Bleue Park was carried out between June 1991 and January 1992. A total of 491 adult Kagus, including 208 pairs, were recorded in 84 of the areas, mostly in the Southern Province (403 birds, 177 pairs). Low Kagu numbers (one to four birds) were recorded in 56% ( n = 47) of the areas. More than nine Kagus were recorded in each of 19 areas, which accounted for 57% ( n = 282) of all birds. In these 19 areas, virtually all birds sang from intact forest. Kagu distribution was fragmented over a large area of the island, but birds occurred mostly in inland mountainous regions. Generalized linear modelling was used to investigate associations between Kagu numbers and eight environmental variables measured at each area. A minimal adequate model without interactions indicated that larger numbers of Kagus were in remoter habitat and on volcanic rock types. These results supported the qualitative analyses in previous surveys. A minimal adequate model with interactions suggested that greater numbers of Kagus were likely to be present with increasing remoteness from human settlements. The Kagu population is now fragmented amongst remote patches of habitat, and the results suggest this is most likely because of human‐associated factors. Additional managed reserves to protect significant numbers of Kagus are urgently needed to ensure birds remain throughout the island and in a variety of biotypes.