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18/07/2014
The North American ruddy duck is an invasive alien species in Europe, which threatens the native white-headed duck through hybridisation. A substantial population established in the UK following escapes and releases beginning in the 1950s. The species then spread widely within Europe, and viable populations established in Belgium, the Netherlands, France and Spain. An international plan to eradicate the species from Europe has been adopted, but the approaches and intensity of control have varied widely between countries. The European Union is considering a new legislative instrument on Invasive Alien Species, which is likely to place responsibilities on member states to control named species. Coordinated control across those member states with remaining ruddy duck populations is likely to be an early test of any new responsibilities, with the potential to achieve the first continental scale eradication of an invasive alien species. informacion[at]ebd.csic.es: Robertson et al (2014) Towards the European eradication of the North American ruddy duck. Biol Invasions. Doi 10.1007/s10530-014-0704-3
15/07/2014
Although variation in the dorsal plumage colour of male European Pied Flycatchers Ficedula hypoleuca has received a great deal of attention, females of the species have been usually considered to be nearly uniformly monochromatic brown. Using reflectance spectrophotometry, the age-dependent variation of plumage colour in females has been explored. Disentangling the within- and between-individual effects of this pattern, a within-individual darkening of the mantle colour with age has been shown, whereas differences between individuals in structural colour expression may underlie the trend for a more reflective white in the females´ breast plumage with advancing age. The darkening of the dorsal plumage as females age reflects the most common pattern of age-related variation in males in most European populations of the species. informacion[at]ebd.csic.es: Potti et al (2014) Ontogenetic variation in the plumage colour of female European Pied Flycatchers Ficedula hypoleuca. Ibis. Doi 10.1111/ibi.12175
10/07/2014
Theoretically, spatial overlap and food availability are related in a nonlinear manner with high overlap levels at the extremes of a food availability gradient and low overlap at intermediate levels of this gradient. These predictions have been tested in the Iberian lynx Lynx pardinus, taking advantage of a three-decade data set of spatial behaviour in different scenarios of food availability (i.e. rabbit density). In contrast with expectations, spatial associations between pairs of females were negligible regardless marked variation in prey availability and home range overlap among resident females was low and core area overlap was nearly nil. Lynx would adopt an obstinate strategy of territoriality that consists in defending exclusive areas ensuring an exclusive access to the minimum amount of prey necessary for survival and eventually reproduction even during periods of prey scarcity. Results suggest the occurrence of population regulation through territoriality in this species. informacion[at]ebd.csic.es: López-Bao et al (2014) Revisiting food-based models of territoriality in solitary predators. J Anim Ecol, 83: 934–942. Doi: 10.1111/1365-2656.12226
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    Estación Biólogica de Doñana - Consejo Superior de Investigaciones Científicas - Apdo 1056 E - 41013 Sevilla
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