As avian brood parasitism usually reduces hosts' reproductive success, hosts often exhibit strong defence mechanisms. While such host defences at the egg stage (especially egg rejection) have been extensively studied, defence mechanisms at the nestling stage have been reported only recently. We found a previously unknown anti-parasitism behaviour in the large-billed Gerygone, which is a host species of the little bronze-cuckoo, a host-evicting brood parasite. The hosts forcibly pulled resisting nestlings out of their nests and dumped them. Although it has been suggested that defence mechanisms at the nestling stage may evolve when host defence at the egg stage is evaded by the parasite, the studied host seems to lack an anti-parasitism strategy at the egg stage. This suggests that the evolutionary pathway may be quite different from those of previously studied cuckoo–host systems. Future research on this unique system may give us new insights into the evolution of avian brood parasitism.

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It is well known that wild game provides a significant proportion of the dietary protein of the indigenous people of the eastern half of New Guinea (PNG), but almost nothing is known of its importance in the western half (the Indonesian province of Papua or Irian Jaya). We quantified hunting effort, harvest rates and wild meat consumption and sale in the Jayapura region of north-east Papua through interviews with 147 hunters from 21 villages and meal surveys in 93 households. Ten species of mammals, seven species of birds and at least two species of reptiles were harvested in our study area, but the introduced wild pig and rusa deer were the major target species. Hunting in our study area has shifted from a purely subsistence activity towards a more commercial form at least partly due to the emergence of markets created by Indonesian transmigrants. Although the hunting of non-indigenous and certain native species might be sustainable, the maintenance of populations of large threatened species will require sensitive management.

The density, seasonality, habitat utilization and foraging ecology of birds in mangals (mangrove forests) at a site on the upper reaches of Darwin Harbour were investigated by transect censusing and colour-banding over three years. Despite having only 10 species of plants, the site supported 17 confirmed and five probable breeding resident species of birds, and was visited by 30 more. From variable-width transect censuses, the mean density of birds on a 4-ha plot was estimated to be 25 ha-1, fairly consistent with densities obtained from territory mapping of colour-banded birds. Nearly 70% of the individuals belonged to just 4 species: two mangal-dependent species, the red-headed honeyeater (Myzomela erythrocephala) and the yellow white-eye (Zosterops lutea) and two more generalised species, the large-billed gerygone (Gerygone magnirostris) and the brown honeyeater (Lichmera indistincta). Only the red-headed honeyeater showed significant seasonal variation in abundance, with highest numbers during the late dry season after breeding. This coincided with the period of greatest food (nectar) availability in the mangal, due to flowering Bruguiera exaristata. Lowest numbers of the red-headed honeyeater (and the brown honeyeater) occurred in the late wet season when nectar was scarce in the mangal but abundant in Melaleuca cajuputi fringing the mangal. Several resident species held permanent territories, while others apparently shifted landward during the wet season, possibly due to the wetter conditions created by freshwater runoff and high spring tides Many species showed strong associations with particular mangal zones. Large-billed gerygones, grey whistlers (Pachycephala simplex), shining flycatchers (Myiagra alecto) and mangrove fantails (Rhipidura phasiana) were associated with the Rhizophora zone at the wetter (more frequently inundated) end of the plot; mangrove robins (Eopsaltria pulverulenta) and mangrove gerygones (Gerygone laevigaster), were encountered most in the Ceriops zone; and green-backed gerygones (Gerygone chloronata) strongly favoured the dry landward edge. Four foraging guilds were evident among 13 of the most abundant species, the largest of which was the insectivorous foliage-foraging guild. Species in this group partitioned resources by differential selection of mangrove species, heights and foraging techniques. The tiny (6.4 g) mangrove gerygone was the most specialized species, spending 80% of its time on Avicennia marina. Contrary to the literature, breeding of mangal-dwelling birds peaked during the dry season. The ecology, evolution and biogeography of mangrove-endemic birds is reviewed in the light of this study and recent information from Western Australia.

We compared the bird and woody plant communities of 2 to 24-year-old rehabilitation areas at Gove bauxite mine (20 km 2 ) in the seasonal tropics of northern Australia, where Alcan has maintained a consistent rehabilitation program since it began operation in 1974. Birds were censused every second month over 2 years in 30 widely separated 0.25-ha plots, representing five chronosequence stages. These were also compared with six (''off-mine'') plots adjacent to the mine, which represented the annually burnt open forest typical of the region. Short-lived Acacias dominated the early chronosequence stages, whereas eucalypts dominated in later stages. Mean avian species richness and abundance increased significantly along the chronosequence, with values for the oldest rehabilitation plots being very similar to those for the off-mine plots. However, analyses of similarity revealed that the bird communities of the oldest rehabilitation plots were distinct from those of the off-mine plots, indicating that succession in rehabilitation areas is not following a direct trajectory toward the native open forest surrounding the mine. Several hollownesting bird species were scarce or absent in the rehabilitation areas, probably reflecting the absence of older hollow-bearing trees. Many differences between the rehabilitation and the off-mine areas in vegetation structure, woody flora, and avifauna appear to be related to the exclusion of fire from the minesite. We recommend the initiation of experiments designed to assess the effects of fire on the biota but caution against the use of fires for the majority of rehabilitation areas.