Factors affecting the cost of polygynous breeding for female Great Reed Warblers Acrocephalus arundinaceus

The male's role in feeding young and his effect on the mortality of eggs and nestlings of the Great Reed Warbler Acrocephalus arundinaceus were studied in Kahokugata, central Japan, during eight breeding seasons. Three potential costs of polygynous breeding for females were examined:(i) a reduction of male parental care per brood, (ii) an attraction of predators due to concentration of nests, and (iii) an increase of unfertilized eggs due to the reduced frequency of copulation per female. Only the first cost was found to occur:polygynous males fed their young, especially of their second broods, less frequently than monogamous ones. The lowered paternal feeding frequency, however, did not increase the mortality by starvation in second-hatched broods. This was because the warm climate emancipated females from brooding and enabled them to compensate for the deficiency of feeding by males. The paper discusses possible roles of the staggering of the time of laying among harem mates and the shift of breeding status of females caused by nesting failure, in reducing potential costs of polygynous breeding for females.     

Group composition and contributions to breeding by Rufous Vangas Schetba rufa in Madagascar

The social system of the Rufous Vanga Schetba rufa was studied in a deciduous dry forest in Ampijoroa, western Madagascar. The species lived in groups of two to four individuals. Groups typically contained one adult female, one or two adult males and sometimes a (presumed) immature. All group members appeared to defend the territory. The presumed immatures had spotted throats and were smaller than adults in body size. They helped feed young and guard the nest but did not incubate or brood.     

Early settling the following spring: a long-term benefit of mate desertion by male Great Reed Warblers Acrocephalus arundinaceus

In a population of the Great Reed Warbler Acrocephalus arundinaceus in central Japan 33 cases of mate desertion by males were recorded during eight breeding seasons. Thirty of these occurred at the end of the breeding season. The absence of the male parent during the nestling period affected neither the frequency of nestling starvation nor the return of females. Eight deserters were confirmed to have begun moulting prior to the fledging of their young. Males which had abandoned their territory relatively early in the summer tended to settle earlier and to be polygynous the following spring. As earlier settling is an important factor influencing polygyny in males, an increased chance of early settling the following season can be regarded as a long-term benefit of mate desertion.     

Different habitat use among three sympatric species of couas Coua cristata, C. coquereli and C. ruficeps in western Madagascar

This study compares the habitat use by three species of couas, the Crested Coua Coua cristata , Coquerel's Coua C. coquereli and the Red-capped Coua C. rujiceps , in a dry forest at Ampijoroa, western Madagascar. The Crested Coua used higher layers (> 5 m) exclusively. Both Coquerel's and the Red-capped Coua stayed mainly on the ground, but the former used middle layers (1–5 m) for inactive behaviour (including resting, preening and basking) and whistling more frequently than did the Red-capped Coua. Both Coquerel's and the Red-capped Coua foraged almost exclusively on the ground but differed slightly in feeding technique. The Red-capped Coua took food on trails, relatively open areas in the forest, more frequently and more efficiently than Coquerel's Coua.