Relationship between bird‐unit size and territory quality in three species of fairy‐wrens (Malurus spp.) with overlapping territories

Abstract

The relationship between unit size and territory quality and size was examined in variegated, superb and red‐backed fairy‐wrens in an area in which the birds’ territories overlapped extensively. Variegated fairy‐wrens had the least number of paired birds and the largest mean unit size. More than half of the superb and red‐backed fairy‐wrens occurred in pairs. Territory size did not differ between the species. A positive correlation between unit size and territory size was found only in the variegated fairy‐wren. Stepwise regression analyses with backward elimination on 10 habitat variables showed that unit size was associated with different territory‐quality measures in the three fairy‐wren species. It is suggested that species that are more inclined to form pairs or small groups during the breeding season are also more sensitive to ecological factors and prefer not to form large groups in a resource‐limited environment.

Radical loss of an extreme extra-pair mating system

“…The following data were not available from these sources and were obtained from other studies, where possible from the same population in which EPP was studied: group- [67] and territory-size in M. melanocephalus and M. splendens [68,69], % inbreeding in M. cyaneus [37], number of annually raised broods [33,70] and annual divorce rates in M. cyaneus and M. splendens [35,36]. Divorce rates in M. melanocephalus are low, but not yet quantified (M.S.…”

Impacts of Fire on the Group Composition of the Red-backed Fairy-wren Malurus melanocephalus cruentatus in the Non-breeding Season

“…This species forms large flocks in the non-breeding season (Rowley & Russell 1997, Chan & Augusteyn 2003. Aggregating in a large non-breeding flock may be adaptive to exploit patchily distributed food resources in winter (Krebs & Davies 1981).…”

“…To date, almost all information about the social structure and breeding ecology of this species has been collected from the eastern race (Rowley & Russell 1997). Whilst the breeding biology of the species has been studied (Karubian 2002, Chan & Augusteyn 2003, there have been no studies of its social organisation, such as group composition and stability, during the non-breeding season, when flocks of up to 20 birds have been reported (Chan & Augusteyn 2003). Limited evidence suggests that groups tend to leave territories and aggregate in large flocks in the non-breeding season and then return to previous territories in subsequent breeding seasons (Rowley & Russell 1997).…”

Group size correlates with territory size in European badgers: implications for the resource dispersion hypothesis?

“…Th e current study suggests that territory size in badgers is not purely the product of resource dispersion, as predicted by the RDH (Johnson et al 2002a), but is instead positively related to group size. Examples of similar positive correlations between territory size and group size exist for other social carnivores (Macdonald 1983), birds (Chan and Augusteyn 2003) and rodents (Schradin and Pillay 2004). In territorial animals the benefi ts of holding a territory are off set by the that the benefi ts of territory acquisition diff er between the sexes (Boydston et al 2001).…”