Diet composition of young and adult Northern Grey-headed Sparrow Passer griseus and adult Southern Red Bishop Euplectes orix in Burundi

摘要

We studied the diet composition of Northern Grey-headed Sparrow Passergriseus and Southern Red Bishop Euplectes orix in four localities of theRusizi Plain, northwest Burundi. We analyzed crop contents of 100 adultsfrom each of the two species and the composition of food brought by parentsto nestlings of the sparrow at ten nests. In all four sites, the sparrow’s dietconsisted primarily of rice. The bishop also fed mostly on rice grains but alsoate Lepidoptera caterpillars, some other insects and wild grass seeds such asPanicum sp. and Brachiaria sp. For adults of both bird species, there was nosignificant variation in diet throughout the year. However, the diet of youngsparrows was much more diverse and changed from the day of hatching untilfledging. On the day of hatching, chicks ate mainly caterpillars but by thetenth day, food items comprised one third caterpillars, one third Orthopteraand the rest of other insects including Odonata, Dictyoptera, Isoptera andadult Lepidoptera. After this and until fledging, the chicks were fedincreasingly on rice seeds. Simultaneously, the proportion of caterpillars takengradually decreased until none was fed to the nestlings at the end of thenestling period. The items brought by parents also varied with time of day,with caterpillars and grasshoppers in higher proportions in the morning,decreasing around mid-day and then increasing in the evening.