The intrinsic properties and widespread presence of plastic particles in the marine environment have profound effects on birds inhabiting the world's oceans. Industrial and user-plastics composed of polystyrene, polypropylene, polyethylene, styrofoam, and polyvinyl chloride are the most prevalent forms of plastic marine pollution. Their dispersal and accumulation, in average densities of 1000 to 4000 pieces km-2, are controlled by surface currents, wind patterns, and different geographic inputs. Seabirds in the order ProceUariiformes are most vulnerable to the effects of plastic ingeshon due to their smaller gizzard and their inability to regurgitate ingested plastics. Planktivores have a higher incidence of ingested plastics than do piscivores as the former are more likely to confuse plastic pellets with copepods, euphausiids, and cephalopods. Hence, &et may be a major factor determining the quantity of plastic ingested. Physiological effects related to the ingestion of plastics include obstruction of the gastrointestines and of subsequent passage of food into the intestines, blockage of gastric enzyme secretion, diminished feeding stimulus, lowered steroid hormone levels, delayed ovulation and reproductive failure. As plastic manufacture and use increases and subsequent disposal at sea becomes more extensive, the impact of dscarded plastic on birds inhabiting the marine environment may also be expected to increase. WiLliarn Beebe

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12Methods to obtain moult data from wild birds have not changed much over the

Wildlife reintroduction strategies aim to establish viable long–term populations, promote conservation awareness and provide economic benefits for local communities. In Portugal, the Eurasian red squirrel (Sciurus vulgaris) became extinct in the 16th century and was reintroduced in urban parks in the 1990s, mainly for aesthetic and leisure purposes. We evaluated the success of this reintroduction in two urban parks and here described the critical steps. We assessed habitat use, population density and abundance, and management steps carried out during reintroduction projects. Reintroductions have been successful to some extent given squirrels are present 20 years after release. However, populations in both parks are declining due to the lack of active management and poor quality habitat. Successful reintroduction of Eurasian red squirrel in areas without competition of alien tree squirrels involves three critical main stages. The pre–project stage includes studies on habitat quality, genetic proximity between donors and closest wild population, and health of donor stocks. In the release stage, the number of individuals released will depend on resource variability, and the hard release technique is an effective and economically viable method. Post–release activities should evaluate adaptation, mitigate mortality, monitor the need for supplementary feeding, provide veterinary support, and promote public awareness and education.

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Identifying sexes in birds from visual observations is a very useful and inexpensive method. While sexual dichromatism and ornaments are readily used by observers, sexual size dimorphism can also be used to identify sexes in some bird species. This study assessed the applicability of visual observation of size differences in order to identify sexes in adult Black Skimmers (Rynchops niger). Black Skimmers do not have sexual dichromatism however males are larger in size and weight than females. The study focused on two sub-species: Amazonian (R. n. cinerascens) and South American (R. n. intercedens) Black Skimmers. Sex identified by visually observating size differences was consistent with the sex identified at specimen preparation from examining gonads (RGLMM = 0.996 ± 0.004). The identification of sexes from photographs using visual observation of size had a very high within-(RGLMM = 0.995 ± 0.001) and between-(RGLMM = 0.984 ± 0.002) observer repeatability. Non-invasive methods for identifying sex by visual observation may allow enhanced use of data from photographic datasets, citizen science projects, and surveys using direct observation or images.