HABITAT ASSOCIATIONS OF LAND BIRDS IN FERNANDO DE NORONHA, BRAZIL

ABSTRACT Fernando de Noronha is one of few archipelagos of Brazil. These islands harbor five species of land birds: two introduced species (House Sparrow, Passer domesticus , and Cattle Egret, Bubulcus ibis ), one widespread dove (Eared Dove, Zenaida auriculata ) and two endemic passerines. The two endemic species, Noronha Vireo ( Vireo gracilirostris ) and Noronha Elaenia ( Elaenia ridleyana ), have been classified as ‘Near Threatened’ and ‘Vulnerable’, respectively. Here, we quantified the abundance of land birds and correlated it to habitat features to assess potential habitat preferences. We carried out 120 five‐minute point counts in October 2009, and correlated bird abundance with percentages of woodland, bushes, low herbs, bare ground, and man‐made habitats in each sample. The abundance of Noronha Vireo and Noronha Elaenia was positively correlated with woodland and bushes cover. The Eared Dove was associated to sites with bare ground, the House Sparrow with man‐made habitats, and the Cattle Egret with low vegetation sites. Abundances of Noronha Vireo and Noronha Elaenia were significantly higher in sites with natural vegetation than in human‐influenced areas. The association between these species and areas with high native vegetation cover highlights their potential vulnerability to human disturbance. RESUMO ∙ Associacoes entre os ambientes e as aves terrestres de Fernando de Noronha, Brasil Fernando de Noronha e um dos poucos arquipelagos do Brasil. Estas ilhas abrigam cinco especies de aves terrestres: duas especies introduzidas ( Passer domesticus e Bubulcus ibis ), uma pomba com ampla distribuicao ( Zenaida auriculata ) e duas especies de passeriformes endemicos ( Vireo gracilirostris e Elaenia ridleyana ). Estas duas especies sao classificadas como “quase ameacada” ( V. gracilirostris ) e “vulneravel” ( E. ridleyana ). Neste estudo, quantificamos a abundancia das aves terrestres e correlacionamos com as caracteristicas de habitat do arquipelago de Fernando de Noronha. Fizemos 120 pontos de escuta de cinco minutos em outubro de 2009, comparamos a abundancia de aves com a porcentagem de ambientes contendo vegetacao arvoborea, arbustos, vegetacao rasteira, solo aberto e construcoes amostradas em um raio de 25m. A abundancia de V. gracilirostris e de E. ridleyana e positivamente correlacionada com porcentagem de cobertura de arvores e arbustos. A abundancia de Z. auriculata esta positivamente correlacionada com a porcentagem de solo aberto, a abundancia de P. domesticus com construcoes e de B. ibis com a porcentagem de vegetacao rasteira. As abundancias de V. gracilirostris e E. ridleyana sao significativamente maiores em locais com vegetacao conservada, distante das vilas. As associacoes entre as esp