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Biodiversity knowledge gaps, which limit scientific research and conservation planning, are especially acute for the most poorly known organisms. Citizen science offers a powerful and effective means to fill these gaps. The recent growth of citizen‐science platforms has resulted in near‐complete coverage of global avian diversity (~11,849 species). Because shrinking knowledge gaps increasingly reveal meaningful absences, we evaluated the potential of citizen‐science data to establish "lost" bird taxa: those without documentation for more than 10 years. Collating more than 42 million photographic, audio, and video records returned 144 bird species (1.2%) as lost, the majority of which (62%) are in danger of extinction. The higher the coverage by citizen scientists and the longer the interval since their last documented record, the more likely that lost birds are to be imperiled. Our approach provides a data‐driven and reproducible method to identify lost species and elucidates high‐priority knowledge gaps to inform future conservation action. [ABSTRACT FROM AUTHOR]

Although lowland tropical rain forests were once widely believed to be the archetype of stability, seasonal variation exists. In these environments, seasonality is defined by rainfall, leading to a predictable pattern of biotic and abiotic changes. Only the full annual cycle reveals niche breadth, yet most studies of tropical organisms ignore seasonality, thereby underestimating realized conditions. If human‐modified habitats display more seasonal stress than intact habitats, then ignoring seasonality will have particularly important repercussions for conservation. We examined the seasonal dynamics of Amazonian mixed‐species flocks, an important species interaction network, across three habitats with increasing human disturbance. We quantified seasonal space use, species richness and attendance, and four ecological network metrics for flocks in primary forest, small forest fragments, and regenerating secondary forest in central Amazonia. Our results indicate that, even in intact, lowland rain forest, mixed‐species flocks exhibit seasonal differences. During the dry season, flocks included more species, generally ranged over larger areas, and displayed network structures that were less complex and less cohesive. We speculate that—because most flocking species nest during the dry season, a time of reduced arthropod abundance—flocks are simultaneously constrained by these two competing pressures. Moreover, these seasonal differences were most pronounced in forest fragments and secondary forest, habitats that are less buffered from the changing seasons. Our results suggest that seasonality influences the conservation value of human‐modified habitats, raising important questions about how rain forest organisms will cope with an increasingly unstable climate. [ABSTRACT FROM AUTHOR]

The article offers information on californius and purpureus as two distinct subspecies of the Purple Finch (Haemorhous purpureus). It explores the first records of purpureus for California and examine the Purple Finch subspecies from specimens and photographs across western North America. It highlights the regular occurrence of purpureus in the western Great Plains states and very poorly farther west.

The article focuses on the first records of European-banded Lesser Black-backed Gull Larus fuscus in America on November 16 and 20, 2002 in Rio Grande de Arecibo, Puerto Rico and on October 7, 1997 at Cold Spring Harbor in Long Island, New York. The sighted gulls were banded in Iceland and the Netherlands. Data from the Christmas Bird Counts (CBC) show that the number of sightings of Lesser Black-backed Gulls in North America has increased rapidly from 1990 to 2005. The contribution of British birds to the American wintering population is explained. It recommends color-banding of wintering birds in America and of birds breeding in Iceland and Greenland.