Evidence of itinerant breeding of the Red‐billed Quelea Quelea quelea in the Ethiopian Rift Valley

Abstract

This paper provides evidence for itinerant breeding by Red‐billed Quelea Quelea quelea in the Ethiopian Rift Valley. Queleas were mass‐marked with aerially applied fluorescent particles in two separate nesting areas in southwestern Ethiopia during June 1981. Marked adults from both areas were recovered from nesting colonies in the Awash River Valley during August and September, up to 100 days post‐spray and between 500 and 700 km to the north of the spray sites. In the Awash colonies, the presence of marked adults in breeding plumage with interrupted primary wing‐moult, together with two age classes of juveniles, suggests that this was the second nesting. The progress of both the post‐breeding and post‐juvenal primary moults was consistent with an earlier breeding in May and June. The timing of the arrival and departure of birds from these nesting areas also supported the occurrence of double breeding by the same birds. Furthermore, the composition of black facial mask types of adult males was more similar between samples from the southern Ethiopian Rift and Awash Valley than between samples from either of these areas and samples from outside the Rift, providing additional evidence that the same population of birds bred in these two areas of the Rift Valley.Nesting colonies in both areas were scattered in time and space. Colonies in the Awash were distributed for more than 300 km and were established over a two‐month period, which coincided with local differences in the timing of the seeding in grasses. This wide distribution probably increases nesting success in such areas of locally variable rainfall. This contrasts with a stategy of mass migration, where concentrated breeding occurs where and when suitable conditions are first encountered.Knowledge of the location and timing of previously successful nesting areas may increase the success of itinerant breeding, as Queleas seem to use the same areas in successive years if conditions are favourable. Recoveries of marked birds in the Awash were segregated according to both spray site and sex, suggesting some degree of group cohesion by sex from the first to the second nesting. We speculate that post‐nesting group cohesion of adults may provide a means to maintain the integrity of collective group information on seasonal movements. Group cohesion may be facilitated by the high degree of nesting synchrony within colonies.