Threatened Species - South Australian Glossy Black-Cockatoo - A Gradual Recovery

• Introduction
• Population Monitoring
• Recruitment
• Nest Failure
• A Community Effort
• Newsletter
• Program Support
• Contacts

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Introduction

Glossy Black-Cockatoo (Photo: L Pedler)

The South Australian subspecies of Glossy Black-Cockatoo Calyptorhynchus lathami halmaturinus is currently listed as endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and also in South Australia (National Parks and Wildlife Act, 1972). At present it is restricted to Kangaroo Island and prior to the implementation of the recovery project the population was estimated to be 200 individuals and declining. In 1995 a recovery plan was implemented and since then this downward trend has been reversed.

The SA Glossy Black-Cockatoo requires high quality Drooping Sheoak Allocasuarina verticillata woodland for foraging and large hollow-bearing eucalyptus for roosting and nesting habitat. The chief cause of the Glossy Black-Cockatoo's decline in the 1900s was the large-scale clearance for farming of large old gum trees and important sheoak feeding habitat.

The long term objectives of the current Recovery Plan (700Kb PDF) are:

(1) To ensure that a viable breeding population of the Glossy Black-Cockatoo persists in South Australia;

(2) To shift the status of the Glossy Black-Cockatoo from Endangered to Vulnerable within 25 years (ie by 2028);

(3) To expand the current distribution of the Glossy Black-Cockatoo to include its former range on Fleurieu Peninsula.

Recovery Plan actions are:

• Action 1: Survey and monitor the population
• Action 2: Monitor nesting and find new nests
• Action 3: Protect and maintain natural and artificial nest hollows
• Action 4: Minimise the impacts of other bird species
• Action 5: Protect and re-establish GBC habitat on Kangaroo Island
• Action 6: Protect and re-establish GBC habitat on Fleurieu Peninsula
• Action 7: Promote and facilitate community participation

Population Monitoring

Current Status - Endangered

With the benefit of several years of observations, biologist Lynn Pedler has shown that the number of Glossy Black-Cockatoo young produced has increased over the past eight years. (See census results 50Kb PDF) . The increase in population size has most likely resulted from increased nesting success due to protection of nest trees from possums and to the provision of around 80 artificial hollows.

Analysis of flock sizes during the annual population census indicates that the population has increased gradually, from less than 200 birds in 1996 to a minimum of 300 birds in 2005.

Recruitment

Plumage observations made during the 2005 census indicate that the population has a strong component of juvenile/immature birds, with at least one fifth of the population less than three years old. Most of these birds have been banded as nestlings.

Observations of banded individuals indicate that about half of fledged young survive their first year. After the first year, mortality rate is thought to be low. The birds' lifespan is unknown.

Nest Failure

Juvenile Glossy Black-Cockatoo (Photo: L Pedler)

Earlier research indicated that predation of eggs and young chicks by the Common Brushtail Possum was a major cause of nest failure. Exclusion of possums from nest trees with iron collars has increased nest success from 23% in nests that were unprotected in 1996 (Garnett et al. 1999), to an average of 49% in 1997–2003, when all nests were protected. (See nesting results [50Kb PDF])

Infrequent monitoring of active nests means that it is often hard to determine the causes of nest failure. During the last six seasons, failure of the egg to hatch was responsible for around 20% of nest failures. Other known causes of failure included: flooding of the nest hollow; predation by Common Brushtail Possums; predation/competition for hollows with nesting Galahs (first recorded on Kangaroo Island in 1913); Little Corellas (first recorded in 1969) and Sulphur-crested Cockatoos.

Ref: Garnett, S.T., Pedler, L.P., and Crowley, G.M. 1999. The breeding biology of the Glossy Black-Cockatoo Calyptorhynchus lathami on Kangaroo Island, South Australia. Emu 99: 262-279.

A Community Effort

During the 2005 nesting season, around 40 volunteers spent in excess of 300 hours assisting with location and monitoring of active nests. Up to 50 volunteers play a vital role in the annual population census.

Landholders are encouraged, through financial assistance, to fence off feeding and nesting habitat and to revegetate priority areas. Greening Australia assists with large-scale revegetation projects.

Newsletter

"Chewings" is a newsletter produced bi-annually for anyone interested in the South Australian Glossy Black-Cockatoo Recovery Program. The newsletter provides interesting facts about the Kangaroo Island population and news regarding volunteer and revegetation activites associated with the Program.

See newsletter

Program Support

• Natural Heritage Trust
• Glossy Black Rescue Fund
• Nature Foundation SA

Contacts

Eleanor Sobey, Department for Environment and Heritage Regional Conservation, Kangaroo Island