An analysis was made of the associations with local habitat features of barbels (Barbus sp.) of a Mediterranean river basin. The analysis was based on the presence data from sampling the upper, middle, and lower reaches of 31 rivers in the middle Guadiana River basin (south-west Spain). Numerous local habitat variables were determined, including the river's size and substratum, physicochemical variables of water, and the aquatic and riparian vegetation. For each species, a univariate analysis was performed using preference indices, and logistic regression was used to construct a parsimonious multivariate model and Gaussian response models with the most influential variables, quantifying the species' limits of tolerance. Distinct habitat associations for every species were obtained, mainly relating Barbus comiza to the larger habitats and higher water levels, Barbus microcephalus to the maintenance of lotic conditions and Barbus sclateri to more fluctuating rivers. Barbus steindachneri showed a different habitat relationship from that of the genetically almost identical B. comiza. Cover played a significant role in all but B. comiza. # 2005 The Fisheries Society of the British Isles

En la Laguna de Fuente Piedra (Málaga, España) se estudian las preferencias de las diferentes especies acuáticas para ubicar sus nidos, detectándose una competencia interespecífica por la ocupación del espigón central y espigones del NE, en especial referente al Flamenco común y Pagaza piconegra, que son además las especies más numerosas. Igualmente se observa una segregación de especies en función de sus preferencias por aguas salobres o no, detectándose asociaciones importantes como es la formada por Láridos y Recurviróstridos. Por su parte, el sincronismo de la fenología reproductora de las especies es pobre, no superando en ningún caso el 40%. SUMMARYIn Fuente Piedra lagoon (Málaga, Spain) we studied the favorite places the different aquatic species choose to lie their nests and we noted an interspecific competence in order to occupy the Central pint and the points in the NE. We found this competence specially remarkable in Greater Flamingo and Gull-billed tern, which are also the most numerous species. We also observed a segregaron of the species regarding their preferences towards brackish or not brackish water and important associations as that between Laridae and Recurvirostridae. With regards to the sincronicity in the reproductive fenology of these species, we found it poor; it never exceeded 40%.

A sexual dimorphism in the postjuvenile moult of the Azure-winged Magpie Cyanopica cyanea cooki is described. Males retain significantly fewer primaries, secondaries, uppe greater primary coverts and rectrices than females. This difference is interpreted as an adaption for mate selection and to improve reproductive success.