Abstract The lowland Atlantic Forest, at altitudes of below 500 m, is highly fragmented, and is home to many threatened species of birds. The Brazilian state of Rio de Janeiro has a high concentration of threatened birds in the Americas and is an important residual of the dense ombrophilous formations of the Atlantic Forest, which includes the Reserva Biológica União, a high priority area for conservation of Atlantic Forest birds. This study compiled empirical and secondary records of threatened birds in this reserve and discusses potential factors determining their local occurrence. Since 2008, regular observations, including transect surveys and mist-netting, in addiction to secondary data, have provided records of 306 bird species, of which 49 appear on red lists at some level (state, national or global), including 34 listed as endangered, of which 13 are listed globally, eight of them dependent on well-conserved lowland rainforest. Future studies should include new areas of the reserve, with the aim of confirming the presence of additional threatened species. The long-term conservation of this fauna will depend not only on the adequate management of the reserve, but also the reestablishment of its connectivity with adjacent forest fragments and upland areas in the state. 50 m fragmented União occurrence 2008 observations mistnetting, mistnetting mist netting, netting mist-netting data 30 4 state, (state global, global , global) 3 endangered 1 globally wellconserved well conserved rainforest longterm long term 5 200 20 2

ABSTRACT Variation in the morphometry of individuals in a population may result from natural or sexual selection. In the present study we investigated morphometric differences between males and females of a bird species endemic to the Brazilian Atlantic Forest, the Hangnest Tody-Tyrant, Hemitriccus nidipendulus (Wied, 1831), with no apparent sexual dimorphism. All individuals (n = 56) were sexed by PCR amplification of the intronic fragments of the CHDZ/CHDW alleles obtained from blood samples, and 12 morphometric measurements were recorded. The molecular configuration was similar to that described for other species of Passeriformes, with males presenting a single band of approximately 360 base pairs (bp), and females with two bands of 360 and 400 bp. Males had significantly larger tarsi and wings than the females, while the females had two larger beak measurements. This indicates that differential selection pressures may be modeling the morphometry of the Hangnest Tody-Tyrant. In the males, larger tarsi and wings may be beneficial for the exploration of the habitat or the acquisition of potential mates, while females with larger beaks may be able to exploit larger food items and forage more efficiently. However, these hypotheses need to be tested empirically in future studies.

ABSTRACT Restinga occurs as a narrow band of coastal habitats throughout the Atlantic Forest, although it presents considerable variation in vegetation structure, which likely contributes to heterogeneity in species inhabiting this endangered ecosystem. The goal of this study is to examine how variation in vegetation and abiotic conditions in the restinga ecosystem may contribute to heterogeneity of bird communities in Restinga de Jurubatiba, Brazil. Temperature, relative humidity, and vegetation structure were sampled to characterize four sites (dry forest, flooded forest, open scrub and closed scrub). Birds were sampled using observations, mist-netting and voice recordings. Results indicate that major differences of all variables occur between forest and scrub in both vegetation and birds. In addition, differences also exist within forests and within scrub, resulting in considerable heterogeneity among sampled areas. Scrub sites were richer in bird species (n = 58) than forest sites (n = 41), while closed scrub had the most species (n = 49). Also, 64% (47 of 73) of bird species were exclusive to forest or scrub habitats. Scrub habitats were more similar to each other than forest habitats. Normalized Difference Vegetation Index (NDVI) calculated from satellite images distinguished scrub sites and may be useful to monitor changes in vegetation patches through time. The restinga ecosystem is quite heterogeneous with considerable turnover in bird species composition and differences in vegetation structure. Forest strips may serve as connectors on the landscape and to help maintain species diversity and conservation of forest species. Also, this highly dynamic ecosystem, which includes a mosaic of habitat types, likely promotes resilience of bird populations under changing conditions.