Noisy Scrub-bird (Atrichornis clamosus) Recovery Plan

Alan Danks1, Andrew A. Burbidge2, Allan H. Burbidge2 and Graeme T. Smith3
ISSN 0816-9713

3. RECOVERY OBJECTIVES, STRATEGY AND CRITERIA

3.1 Objectives

The long term objective of Noisy Scrub-bird management is to increase the number of subpopulations and individuals of the Noisy Scrub-bird until it can be removed from threatened species lists, and intensive management is no longer necessary for its survival.

To allow upgrading from Endangered to Vulnerable two of the following Mace and Lande (1991) criteria would have to be met:

  • a)total effective population Ne more than 500 (or total N more than 2500);
  • b)population fragmented with at least 5 subpopulations with Ne greater than 100 (N greater than 500) with immigration rates greater than 1 per generation;
  • c)population not subject to catastrophic crashes (in the Noisy Scrub-bird this would primarily be due to wildfire).

The Albany Management Zone does not contain enough habitat to support a scrub-bird population large enough and with sufficient subpopulations to meet the criteria for Vulnerable. Current (1994) numbers in this zone are estimated to be about 1100, with only two subpopulations exceeding 100 singing males. Upgrading the species' listing to Vulnerable under the Mace-Lande criteria therefore requires the establishment of additional large populations. Noisy Scrub-birds will always be prone to catastrophic crashes due to the effects of wildfire; however, the existence of several subpopulations will reduce the effect of fire on the populations as a whole.

The objectives of this Recovery Plan are therefore:

  • 1.In the Albany Management Zone to achieve and maintain a population size indicated by more than 300 singing males, and
  • 2.To commence the establishment of populations in a western management zone.

It is important to note that a major wildfire in either of the Mt Gardner or Mt Manypeaks areas would reduce the number of birds considerably (see Table 1). Since wildfires in these areas are highly likely to occur from time to time, the Recovery Plan is based on the assumption that there will be a significant wildfire in one, but not both, of these areas over the next ten years.

3.2 Strategy for recovery

This Recovery Plan will run for a term of ten years from 1993 to 2002 inclusive. Four primary strategies will be implemented concurrently during this period and are presented below.

  • 1)In the Albany Management Zone:
    • a)develop and maintain a census size of at least 300 singing males by translocation, habitat management and protection of corridors,
    • b)regularly monitor the scrub-bird population at all sites where it occurs including those to which translocations have occurred,
    • c)ensure that existing genetic variability of Noisy Scrub-birds is maintained, by obtaining information on the genetic variability of the original Mt Gardner population and of populations derived from it. If translocated populations show significant loss of genetic variability, develop procedures to minimise or prevent such loss,
    • d)complete and implement a Management Plan for Two Peoples Bay Reserve. The highest priority goal in the Two Peoples Bay Management Plan is to conserve the Noisy Scrub-bird, Western Bristlebird, Western Whipbird and Gilbert's Potoroo. The Reserve will be managed to maintain the existing suitable Noisy Scrub-bird habitat and provide scrub-birds for the translocation program. It will also be a focus for presenting information to the public about the Noisy Scrub-bird and this Recovery Plan.
    • e)on other public lands managed by CALM, ensure the maintenance of areas of suitable scrub-bird habitat and maintain and improve areas of natural vegetation that are or have the potential to be corridors allowing the movement of birds between areas of population concentration, and
    • f)for scrub-bird populations on other lands, encourage, assist and provide advice to relevant land owners or managers to enable them to maintain scrub-bird habitat. Encourage the maintenance or development of appropriate scrub-bird corridors on private land and other public lands.
  • 2)To develop a new management zone (or zones) west of Albany preferably with a long term capacity of at least 300 singing males by:
    • a)finding and preparing at least two separate areas each suitable for developing new population concentrations. Within these areas it should ideally be possible to establish subpopulations which are in close proximity to each other and connected by corridors of habitat which facilitate movement of scrub-birds between them, while at the same time being separated sufficiently by distance or management actions to minimise the chance of a single wildfire affecting more than one area.
    • b)translocating scrub-birds into these areas from the Two Peoples Bay population.
    • c)monitoring the release areas by censusing singing males.
  • 3)To improve the availability of information and educational material about the Noisy Scrub-bird. In particular, develop and maintain information displays and other educational projects at Two Peoples Bay Nature Reserve.
  • 4)To continue to raise funds for Noisy Scrub-bird conservation.

Captive breeding was carried out by CSIRO from 1975 to 1981. This project had limited success and showed that captive breeding, while possible, would be difficult and a very expensive operation to produce the numbers necessary for translocation. While there are sufficient animals in the wild populations for translocation, captive breeding is not necessary for recovery.

3.3 Criteria

The criteria for successfully achieving the objectives are:

  • 1.Within the Albany Management Zone:
    • a)the achievement and maintenance of the total number of singing males at above 300,
    • b)the presence of corridors which allow migration and gene flow between all the subpopulations within the management zone, and
    • c)wildfires do not significantly affect both the Mt Gardner and Mt Manypeaks subpopulations within the period of this Recovery Plan.
  • 2.Establishment of at least two subpopulations within a new management zone west of Albany, each with at least 20 singing males and with sufficient habitat for them to increase to at least 40 singing males.
  • 3.Completion and implementation of a Management Plan for the Two Peoples Bay Reserve that provides for the protection and maintenance of extensive areas of habitat suitable for Noisy Scrub-birds.
  • 4.For CALM-managed public lands outside the Two Peoples Bay Reserve on which other subpopulations exist or are established, ensuring that areas of potential or occupied habitat are protected through the preparation and implementation of Interim Guidelines for Necessary Operations or Area Management Plans.
  • 5.Implementation of a program that encourages, assists and provides advice to relevant owners and managers of other lands where scrub-birds occur, to enable them to maintain scrub-bird habitat and/or corridors.
  • 6.The identification, mapping and protection of corridors of native vegetation which allow scrub-birds to move between subpopulations in each management area, including corridors between the Angove and Manypeaks subpopulation concentrations and the Lakes and Mt Taylor subpopulations.
  • 7.Implementation and finalisation of research into site suitability to assist the selection of translocation sites and increase the chances of successful translocations. This will include research into food availability in relation to habitat and radio-tracking of translocated birds.
  • 8.Measurement of genetic variability for the Mt Gardner and Lakes area subpopulations in the Two Peoples Bay Reserve and for the translocated subpopulation at Mt Manypeaks.
  • 9.Implementation of a program to continue to disseminate and improve the quality of information on Noisy Scrub-bird biology and conservation.