THE ABUNDANCE AND MOVEMENTS OF THE AUSTRALIAN WHITE IBIS Threskiornis molucca IN AN URBAN ENVIRONMENT (original) (raw)
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Relative abundance of Australian White Ibis Threskiornis molluca across the Greater Brisbane region
Pest or Guest, 2007
The Australian White Ibis Threskiornis molucca is an unexpected addition to the small number of native birds that have recently moved into urban and suburban areas. The arrival of the species in the Central Business District of Brisbane in South East Queensland has been accompanied by an increase in associated human-wildlife conflicts. In order to provide essential ecological information of the species in this region, a series of studies have been undertaken. The present study attempts to determine the distribution of the Australian White Ibis with respect to six major habitat categories positioned along an 'urban gradient' from the urban centre, through suburban, exurban/rural and industrial areas, to wildland and coastal areas. Foraging ibis were surveyed during vehicle-based transects covering all parts of a 545 km 2 study area. All ibis detected were assigned to one of 218 1.25 km 2 cells, which covered the entire study area. Ibis were detected throughout the area, though they occurred in highest numbers within urban and coastal areas. Ibis were found in 100% of urban cells, 20-55% of suburban, rural/exurban and industrial cells and were absent from all wildland cells. A large number and diversity of foraging substrates were used by White Ibis, with suburban areas providing the largest number.
Local and regional movements of the Australian white ibis threskiornis molucca in eastern Australia
2011
Little is known about the movements of Australian birds. Information is particularly scarce on large, aquatic birds, which are usually diffi cult to access and handle. Their movements are also often complex, and therefore diffi cult to identify. Here we present data on the local and long distance movements of the Australian White Ibis Threskiornis molucca, a highly mobile bird, which as many other waterbirds, continues to decline in its traditional ranges in inland Australia. At the same time it has invaded coastal urban environments, where its high abundances cause many problems and require management. Our analysis of past and present banding studies reveals that Australian White Ibis travel throughout the urban environment and visit landfi lls, where they forage in large numbers. They also conduct long distance movements, which lead birds from breeding sites in south-eastern Australia along the eastern coast to regions further north (Queensland and Papua New Guinea). Young birds r...
Foraging distances and habitat preferences of a recent urban coloniser: The Australian white ibis
Landscape and Urban Planning, 2011
Australian white ibis populations have increased in many urban areas while traditional inland populations have declined. In instances where conflicts have occurred land managers have been licensed to remove nests and eggs and cull adults at a site scale. With the increase in urban populations and local management of the species, there is a need to understand how ibis are using urban resources and how they move through the urban landscape to identify important resources. To gain a better understanding of the connectedness of local urban populations, we fitted 82 birds with radio transmitters at three common habitats: an urban park, a breeding colony and a landfill. Over a period of 48 weeks we found 45% of birds made movements greater than 10 km, with 13% moving greater than 30 km. Ibis were located at up to nine foraging and seven roost sites, demonstrating the connectedness of the population across the study region. Landfills were identified as a major food resource with 63% of ibis (n = 82) located therein, while parks supported local foraging with only 27% of ibis (n = 82) located therein. Our results indicate that ibis showed site fidelity but also interacted on a regional scale within approximately 40 km of their colonies. Accordingly, conservation planning for this species needs to be assessed on a regional basis, not on a localized case-by-case basis. However, further research into the limits of the 'region' is required for this highly mobile colonial species.
2006
The Australian White Ibis Threskiornis molucca is very successful in adapting to and surviving in urban environments. Overabundant and/or large, permanent populations have established in many urban areas of coastal eastern Australia. In urban areas, the Australian White Ibis is currently regarded as a major pest and many agencies aim to reduce its numbers, however, the lack of knowledge on this species has made management difficult. In this study clutch size and fledgling success of Australian White Ibis breeding in Centennial Park, a large urban park in Sydney, were measured. Mean clutch size was 2.70, with a modal clutch size of three. Mean number of fledglings per successful (nestlings hatched) nest was 2.64. While clutch sizes were similar to those reported for ibis in natural and non-urban environments, fledgling success was considerably higher in Centennial Park. This is most likely due to high food availability in urban areas. Management of artificial food sources (e.g. landf...
Context. In the Sydney region, the population of Australian white ibis has dramatically increased from rare observations in the 1950s to a breeding season peak of 8900 in 2008, resulting with human-wildlife conflicts. Within natural habitats across the eastern states, the ibis population has declined, yet within urban environments ibis have been lethally managed for over 30 years. However, limited ecological and no regional population data are available for the Sydney region.
Breeding of the Australian white Ibis Threskiornis molucca in the urban environment
2013
The Australian White Ibis Threskiornis molucca has increased dramatically in the urban environment since the 1970s and requires management. Currently information on its breeding, a prerequisite for appropriate management, is scarce. We studied the reproduction of Australian White Ibises at two urban sites in the wider Sydney area over an entire year. In comparison to non-urban ibises, urban ibises had a longer breeding period, smaller egg volumes and clutch sizes, but a larger range in clutch sizes. The growth rate of ibis chicks is also described. Urban ibises also had a lower hatching success, but a higher mean number of fl edglings/clutch and a higher reproductive success.
Martin et al 2011 Foraging distances and habitat preferences of a recent urban coloniser- The AWIbis
Australian white ibis populations have increased in many urban areas while traditional inland populations have declined. In instances where conflicts have occurred land managers have been licensed to remove nests and eggs and cull adults at a site scale. With the increase in urban populations and local management of the species, there is a need to understand how ibis are using urban resources and how they move through the urban landscape to identify important resources. To gain a better understanding of the connectedness of local urban populations, we fitted 82 birds with radio transmitters at three common habitats: an urban park, a breeding colony and a landfill. Over a period of 48 weeks we found 45% of birds made movements greater than 10 km, with 13% moving greater than 30 km. Ibis were located at up to nine foraging and seven roost sites, demonstrating the connectedness of the population across the study region. Landfills were identified as a major food resource with 63% of ibis (n = 82) located therein, while parks supported local foraging with only 27% of ibis (n = 82) located therein. Our results indicate that ibis showed site fidelity but also interacted on a regional scale within approximately 40 km of their colonies. Accordingly, conservation planning for this species needs to be assessed on a regional basis, not on a localized case-by-case basis. However, further research into the limits of the 'region' is required for this highly mobile colonial species.
Behavioural adaptation of a bird from transient wetland specialist to an urban resident
PloS one, 2012
Dramatic population increases of the native white ibis in urban areas have resulted in their classification as a nuisance species. In response to community and industry complaints, land managers have attempted to deter the growing population by destroying ibis nests and eggs over the last twenty years. However, our understanding of ibis ecology is poor and a question of particular importance for management is whether ibis show sufficient site fidelity to justify site-level management of nuisance populations. Ibis in non-urban areas have been observed to be highly transient and capable of moving hundreds of kilometres. In urban areas the population has been observed to vary seasonally, but at some sites ibis are always observed and are thought to be behaving as residents. To measure the level of site fidelity, we colour banded 93 adult ibis at an urban park and conducted 3-day surveys each fortnight over one year, then each quarter over four years. From the quarterly data, the first year resighting rate was 89% for females (n = 59) and 76% for males (n = 34); this decreased to 41% of females and 21% of males in the fourth year. Ibis are known to be highly mobile, and 70% of females and 77% of males were observed at additional sites within the surrounding region (up to 50 km distant). Our results indicate that a large proportion of ibis have chosen residency over transience both within the study site and across the broader urban region. Consequently the establishment of refuge breeding habitat should be a priority localised management may be effective at particular sites, but it is likely to have an impact across the broader population.
Waterbirds, 2019
The roosting ecology of most waterbird species is poorly known and even less is known from southern Asia, where many species inhabit human modified areas. Roosting ecology of the Black-headed Ibis (Threskiornis melanocephalus) was studied in urban and rural settings in southern Rajasthan, India. Analyses focused on assessing whether site characteristics varied between nest sites, urban and rural roost sites, and paired sites (i.e., a waterbird roost site near Black-headed Ibis roosts but without Black-headed Ibis). Additionally, the hypothesis that factors affecting Black-headed Ibis numbers at roosts would be similar at urban and rural sites was tested. Tree characteristics (canopy cover, girth at breast height) were different (P < 0.05) between nest and roost sites. Urban roost sites experienced 2.3 times greater disturbance than rural roost sites. Paired site characteristics were similar to urban roost sites (multi response permutation procedure, significance of δ = 0.3), but were dissimilar to rural roost sites. Co-occurring roosting bird assemblages were significantly different between roosts and paired sites (significance of δ < 0.01) in urban and rural settings. Black-headed Ibis numbers at urban roosts were influenced by multiple variables, but models showed considerable ambiguity at rural sites. Results strongly suggest that including roost sites in a species status assessment is important.