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Night‐activity patterns of individually‐caged grey‐breasted silvereyes Zosterops lateralis of resident and migrant status were investigated. True migratory restlessness or ‘Zugunruhe’ was exhibited by some individuals, but there was also considerable ‘noise’ in the data caused by cageing and neighbouring disturbance. In general, ‘Zugunruhe’ took place from about 2 h before, to about 4 h after ‘sunrise’, and both the daily timing and annual duration of Zugunruhe were consistent with the migration pattern observed in the field. A total of 42 % of resident birds from Tasmania, 77 % of migrant birds from Tasmania and 90 % of migrant birds from the mainland were considered to have exhibited true ‘Zugunruhe’, while none of the resident birds from Brisbane were considered to have displayed it. A few individuals spontaneously developed ‘Zugunruhe’ in the absence of other birds, but many birds (both residents and migrants) displayed no elevated night unrest when placed in a room on their own, although displaying unrest when placed among birds exhibiting ‘Zugunruhe’. The migration of the silvereye probably has a genetic basis, but whether an individual migrates or not is also influenced by social factors which differ in magnitude between individuals.

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.

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Multivariate analysis on 15 habitat variables and quantitative data on foraging and interactive be/iaviour were used to Investigate habitat selection in the White-plumed Honeveater (Xichenostomus penicillatusj and the Euscous Honeyeater fLichenostomus fuscus^) at an area of sympatry in wood/and in New England Table/ands. Thirty-nine plots from four sites were used to examine significant differences in habitat uti/ization during the breeding period. The White-plumed Honeyeater associated strongly with narrow belts of riverine Casuarina while the Fuscous Honeyeater was associated with Eucalyptus tn the e.\-tensive euea/ypt woodland. The narrow ecolone was used by both species, but the two occurred together only in an extremely narrow zone. Changes in foraging activities were observed between this overlap zone and non-overlap zone. Both niche breadth and overlap tn re/ation to four measures of foraging were reduced in p/ots where speeies were in joint occurrence compared with where they were not. a/though overlap in most measures of foraging remained high. The number of encounters between the two highly aggressive and abundant speeies was not great. Thus, the speeies appear general/y to avoid eaeh other. The observed spacing pattern may resu/t from prior experience of intense aggressive interactions. Distinct habitat features could provide easily recognized cues for the maintenance of local horizontal separation. Other factors such as slight differences in morphology, habitat preference, foraging and 'Present address:

Many terns (Laridae)