ABsTRACT.-Brum W.M., Da Costa Pereira M.A.V., Vita G.F., Ferreira I., Mello E.R., Aurnheimer R.C.M., Sanavria A. & Padua E.D. 2016 The study intended to analyze the population of migratory and resident wild bird species from Marambaia island, located in the municipality of Mangaratiba, Rio de Janeiro state, regarding the presence of microorganisms in blood smears during the year of 2009. In order to achieve the goal, 86 individuals of 22 bird species were captured using mist nets; peripheral blood was collected and blood smears performed. The birds were released after examined and sampled in situ. The diagnostic results were 11 (12.80%) birds positive for Plasmodium sp., one (1.16%) for microfilaria and 16 (18.60%) for Borrelia sp. Ticks identified as Amblyomma sp. (Ixodidae) were observed parasiting the sampled birds, suggesting that a relationship parasite-vector-host exists between these ticks and the Borrelia genus. This study should be expanded to other regions so that its results may favour other surveys, focused on conservation of wild birds in their habitat.