Aims: To study the spatial associations of non-breeding marbled teal Marmaronetta angustirostris with other wintering waterbirds. To assess the information such interspecific associations can provide about habitat requirements of globally threatened species.
Location: Sidi Bou Ghaba (34º 10' N, 06º 39' W), a closed-basin lagoon on the Atlantic coast of north-west Morocco.
Methods: Flock-scan sampling during eight days in February 1995, five in March 1995 and two in October 1997.
Results: In February and March, marbled teal showed a positive spatial association with gadwall Anas strepera, green-winged teal A. crecca and crested coot Fulica cristata and a negative association with mallard A. platyrhynchos and gulls. There was a very different pattern in October, when marbled teal had a positive association with mallard and a negative one with crested coot. In March, individual marbled teal positioned at different distances to the shoreline were significantly associated with different waterbird species along a continuum from crested coot (closest to shoreline) to greater flamingo Phoenicopterus ruber (farthest). Similarly, individuals in different behaviours were associated with different waterbird species, those swimming being most associated with flamingos and northern pintail A. acuta. This is because swimming teal tended to be in the most open areas frequented by these species.
Conclusions: The interspecific associations of marbled teal covary with the behaviour and microhabitat use of individual birds. Studying the spatial association between a threatened species and other birds can provide misleading information on the habitat requirements of the former if results are inconsistent over space and time. This illustrates the complexities of studying the habitat selection of waterbirds.
