Search

Delayed natal dispersal is thought to have evolved in response to survival benefits of philopatry and group formation under environmental and/or demographic constraints, with kin selection subsequently promoting the emergence of cooperative breeding behaviours. We studied sociality and natal and breeding dispersal of a colour-banded population of Eastern Yellow Robin Eopsaltria australis over 10 years to better understand the evolution of facultative cooperative breeding in this long-lived, territorial songbird. Breeding group size averaged 3.08 (range 2–6) adults and 82% of helpers were males. All male young delayed dispersal to help one or both parents (82.1%), another first order relative (12.5%) or other relatives (5.4%) for between one and four years before establishing as a dominant breeder. The social relationships of female helpers was confirmed in only two instances, with the helper being the daughter of the breeding pair. Helpers significantly increased annual productivity, which averaged 1.44 (95% confidence intervals: 1.07–1.81) with no helpers and 2.04 (95% confidence intervals: 1.74–2.34) with helpers present. Male young were highly philopatric; most either inherited the natal territory or budded off a portion of the natal territory, and none dispersed more than one territory away. Most females appeared to disperse further after reaching independence to become floaters. Breeding dispersal was limited to females, who dispersed after either divorce or to avoid incest once a son inherited the territory. These results confirm that Eastern Yellow Robin helpers likely gain indirect fitness benefits from helping. [ABSTRACT FROM AUTHOR]

Copyright of Avian Research is the property of KeAi Communications Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Migratory connectivity describes the extent to which migratory species' populations are connected throughout the annual cycle. While recognized as critical for understanding the population dynamics of migratory species and conserving them, empirical evidence of links between migratory connectivity and population dynamics are uncommon. We analyzed associations between spatiotemporal connectivity and differential population trends in a declining and endangered migratory shorebird, the far eastern curlew (Numenius madagascariensis), with multiyear tracking data from across the Australian nonbreeding grounds. We found evidence of temporal and spatial segregation during migration and breeding: curlew from southeast Australia initiated northward migration earlier, arrived at breeding sites earlier, and bred at lower latitudes than curlew from northwest Australia. Analysis of land modification intensity revealed that populations from southeast Australia face greater human impacts compared to those from northwest Australia at both the breeding and nonbreeding grounds, a pattern that aligns with steeper population declines in southeast Australia. This alignment between migratory connectivity, human impacts, and differential population change highlights the importance of a full annual cycle approach to conservation that includes mitigating threats on the breeding grounds and better protecting nonbreeding habitats in Australia where far eastern curlew spend over half of each year. [ABSTRACT FROM AUTHOR]

We observed a congregation of Rufous Whistlers Pachycephala rufiventris perform courtship displays toward each other on multiple occasions, a previously undocumented behaviour. We posit that the location of the courtship behaviour represented a communal display area and the behaviour arose either because of individuals congregating at an established location to form pair bonds, or because the location was at a shared territory boundary where individuals gathered to defend their territories, which led to courtship behaviour between multiple individuals. Our observations provide new insights into the courtship behaviour of Rufous Whistlers and we suggest how future work could offer insight into the origin and function of communal display behaviour in this species. [ABSTRACT FROM AUTHOR]

This study provides further insights into the migration of Pacific Golden Plover spending the nonbreeding season in Eastern Australia using leg flag resightings and Platform Terminal Transmitters (PTTs). Four Pacific Golden Plover in Moreton Bay, Queensland, Australia were fitted with 5g PTTs and their local non-breeding season movements and migration monitored. Three of the four birds migrated, with two failing to complete the first migration leg and one reaching Guam where it stopped over for nine days before flying to Japan. In Japan, it utilised three stopover sites before leaving and flying to Gareloi Island, one of the Aleutian Islands in Alaska. Migration speeds of between 49.4 km.hr- 1 and 83.7 km.hr-1 were recorded at different points in the migration. Local movements prior to migration indicated that the birds were faithful to their primary roosting sites and typically only ranged within a few kilometres of that location. The usage of both artificial and natural roosting and feeding areas is discussed and the importance artificial sites for migratory shorebirds highlighted. Differences in foraging behaviour at night were also identified and potentially were linked to disturbance factors. [ABSTRACT FROM AUTHOR]

Between September 2006 and December 2016, a total of 553 Grey-tailed Tattler were caught in Moreton Bay, Queensland, Australia and fitted with green, engraved leg flags facilitating identification of individuals in the field. Over the period of the study this has resulted in 2905 individual resightings within Moreton Bay and a further 76 resightings further afield, of which 70 were in Japan. Between 2011 and 2013, 41 geolocators were also fitted to obtain more detailed data on the migratory behaviour of this species. Three of these were retrieved and provided data on the timing, speed and individual variability in migration, as well as information on staging and breeding areas. Data from the three geolocators demonstrated that all three birds migrated to staging grounds in Japan before moving north to breed in Northern Kamchatka or Southern Chukotka. One bird had an additional staging period in the northern Philippines and all three birds arrived on the breeding grounds within three days of each other. Southward migrants took a more easterly and direct route back to their Australian non-breeding areas. [ABSTRACT FROM AUTHOR]

The identification of the sex of individuals is important for the investigation of gender roles in the behavioural ecology of species and sex-specific differences in demography. We investigated the extent of sexual size dimorphism in the Eastern Yellow Robin (Eopsaltria australis), a species with no sex differences in plumage, and the utility of morphometric traits to sex adult and juvenile birds. Using a sample of adult birds sexed on the basis of sexspecific breeding behaviour, we found strong sexual dimorphism in all morphometric traits measured, namely total head length, wing chord, body mass, tarsus length and tail length, with males being larger than females. Total head length was the most reliable measure to use to sex adult Eastern Yellow Robins, showing the greatest repeatability and no overlap in the measurements of males and females. Total head length averaged (± 1 s.d.) 40.1 ± 1.0 mm among adult males and 36.7 ± 0.4 mm among adult females. Juvenile birds captured within the first month of fledging showed no subsequent change in body mass and tarsus length between juvenile and older ages, and a two-way plot of body mass and tarsus length provides a reliable method for sexing juvenile birds. [ABSTRACT FROM AUTHOR]

South temperate Australian passerines are generally long-lived compared to birds of the north temperate region. However, few data are available on the survivorship of tropical and subtropical Australian birds. We examined survival in the Mangrove Gerygone Gerygone laevigaster at a sub-tropical location in Brisbane, south-east Queensland. Based on a dataset of 414 Mangrove Gerygones banded at three sites separated by a maximum of six kilometres, between 2006 and 2015 we found the species to be highly sedentary, with no movements between sites. No adults were recaptured four or more years after banding, although one bird banded as a juvenile was recaptured 5.5 years after banding. Using a time dependent Cormack-Jolly-Seber live recaptures model for birds banded as adults, the apparent annual survival rate was 43.8 percent. Using a Time Since Marking model resulted in a slightly higher survival rate (46.7%) - excluding potential juveniles and transients. Banding studies in Darwin, Northern Territory, also indicate that this species rarely lives beyond four years of age. As most small Australian passerines studied to date have apparent annual adult survival rates between 55 percent and 85 percent, apparent survival of the Mangrove Gerygone appears atypically low. [ABSTRACT FROM AUTHOR]