Activity period of Southern house wren Troglodytes musculus Naumann, 1823 (Passeriformes: Troglodytidae) on edges of Atlantic Forest fragments in João Pessoa (State of Paraíba, Northeast Brazil)

Abstract

Southern house wren Troglodytes musculus Naumann, 1823 (Passeriformes: Troglodytidae) is widely distributed in Brazil, occurring on the edges of forests and urban areas, considerable a passeriform usually found in antropized landscape. Birds use vocal signs in diverse activities during the circadian cycle (eg.: in reproduction, territorial defense, alert of predators and competitors, individual recognition, etc), employing vocal signs under energetic balance for development of diary activities. The aim of this study was to evaluate the diary activity period of T. musculus through their vocalizations. The sampling were made during two days in edges of Atlantic Forest fragments in João Pessoa, State of Paraíba, Brazil. Using the method of playback, vocal response of Southern house wren was measured in six periods for each day: H1 (5 h-7 h), H2 (7 h-9 h), H3 (9 h-11 h), H4 (11 h-13 h), H5 (13 h-15 h) and H6 (15 h-17 h). Differences among the periods was tested through of Kruskall-Wallis test, and Mann-Whitney test with Bonferroni's corrections. In order to separate the periods groups, was applied Cluster test and non-Metric Multidimensional Scaling. Were registered 2,421 vocalizations, which 2,229 in morning (H1 to H3) and 122 (H4 to H6) in the afternoon period. Results indicated there were differences among the diary activities period of T. musculus (p = 0.0008171), with early hours of morning (H1 and H2) did not differ between each other (p = 0.183), however differing from the others. The H3 and H6 periods also not differ between each other (p = 0.784), but differing significantly from H4 and H5, that did not record no one vocalization (p = 1). Cluster analyses support these results, clustering: Group 1 (H1 and H2); Group 2 (H4 and H5) and Group 3 (H3 and H6). The periods with the highest frequencies of vocal sings (Group 1) showed the most favorable conditions to vocalize, be they microclimatic (better sound transmission due lowest wind intensity and air turbulence) or behaviors (females attraction, territorial invasion, etc.). On the other hand, non-recording of vocalizations of Group 2 suggest unfavorable periods to vocalize. In addition, Southern house wren concentrate their energetic reserves foraging in these periods. The intermediary records of Group 3 indicate that the periods H3 and H6 require an expensive energetic cost to vocalize due the lowest success in an effective communication. In that way, this present study suggest there was a pattern in diary activity period in Southern House Wren populations evaluated, with no overlap of activities, complementing the knowledge of the specie biology and behavior.