CECOAL   02625
CENTRO DE ECOLOGIA APLICADA DEL LITORAL
Unidad Ejecutora - UE
artículos
Título:
Arthropod prey availability and breeding of the threatened Strange-tailed Tyrant (Alectrurus risora)
Autor/es:
ADRIAN S. DI GIACOMO; DI GIACOMO, ALEJANDRO G.; ZERMOGLIO, PAULA F. ; CASTELO, MARCELA K.
Revista:
ORNITOLOGIA NEOTROPICAL
Editorial:
NEOTROPICAL ORNITHOLOGICAL SOC
Referencias:
Lugar: ALEMANIA; Año: 2016 vol. 27 p. 259 - 266
ISSN:
1075-4377
Resumen:
The Strange‐tailed Tyrant (Alectrurus risora) is an insectivorous flycatcher (Tyrannidae) endemic to the natural tall grasslands of northern Argentina and southern Paraguay. Alectrurus risora has a polygynous mating system and the abundance of arthropods could be a major factor determining the establishment of male breeding territories and the extent of the breeding season, which is shorter than in most other reported tyrant flycatchers. To investigate this hypothesis, we examined the abundance of arthropods in upland and lowland breeding habitats. Upland habitats seem to be preferred for breeding, and usually harbour more nests. Data from one year showed that, for both grasslands, the beginning of the breeding season coincides with a greater availability of arthropods, and that the short reproductive season of A. risora coincides with a general lower availability of prey during February and March in the year we conducted the study. In upland territories, males attracted more females and had more active nests than males holding territories in lowland grasslands. However, the abundance and biomass of total arthropods and of potential prey were higher in lowland than in upland grasslands, with the exception of the abundance of Orthoptera, which was higher in upland habitat and could represent one of the major prey items. Therefore, we conclude that 1) female preference for males in upland grasslands cannot be explained by higher arthropod prey availability, and 2) the availability of arthropod prey may be important in determining the extent of the breeding season, although further, multiannual studies are required to corroborate this hypothesis.