Specific Objective: 1. Maximising extent of occurrence and total population size.
Criteria: Breeding distribution of Christmas Island Frigatebirds maintained or increased on Stokes (1988) levels.
Total population size not significantly less than 1620 breeding pairs.
Action: 1. Develop techniques to monitor the total breeding population size.
Develop a census methodology which is less expensive and more easily repeated than that used by Stokes (1988). Stokes surveyed nest distribution, particularly in the golf course colony, each year between 1983 and 1987, and also collected monthly data on breeding success at about 50 nests in 1985/86. Barry Reville carried out more detailed studies of a small number of nests in one tree in the cemetery colony. These data contain information on the attendance at nests by both sexes which is important to help interpret census data, as well as breeding and nesting success - an analysis would be invaluable in developing a census method. Other information that should be extracted from these studies includes: (i) Breeding success (and thus breeding requirements); particularly between years, and sites, (ii) timing of breeding, (iii) overlap between Christmas Island Frigatebirds and Great Frigatebirds in nesting distribution, (iv), information on feeding rates and the relative role of each sex in raising the young.
Frigatebirds are very difficult to catch and sensitive to handling (T. Stokes pers. comm.) and a censusing method will probably involve attempting to count the number of breeding attempts initiated in a particular year. Alternative methods of censusing Christmas Island Frigatebirds need to be evaluated due to the expense of repeating ground-based censuses of the number of nesting birds. Frigatebirds are prone to desertion of their nests and aerial surveys by conventional aircraft should not be considered (T. Stokes pers. comm.). However it may now be practical to develop an aerial census technique using remote-controlled helicopters, which are large enough to carry video or still-camera equipment. The budget provides for the hire of such a helicopter to be used with camera equipment already possessed by the PAN Christmas Island office.
Action: 2. Monitor the total breeding population size.
In order to estimate the size of the breeding population it is essential to monitor the number of pairs which commence breeding each year. Due to the time lag between a breeding attempt and a new breeder entering the population, a decrease in the number of breeding adults will not result in a change in the number of breeding-age adults for at least 10 years and probably longer. There appears to have been a significant loss of breeding habitat in the recent past, so the number of breeding adults may be significantly lower than the number of breeding-age adults. Two surveys should be carried out to determine the status of this species and whether management action is required in the future. Repeated surveys of the number of breeding-age adults will indicate whether the breeding population is currently declining; repeated surveys of the number of breeding adults may indicate whether the population will decline in the future. A survey at the time when frigatebirds are beginning to pair would probably give the best indication of the total population of breeding-age adults. A survey of the number of pairs which begin nesting would also help to determine whether the population is restricted by lack of suitable breeding habitat.
An initial pair of surveys of the whole breeding population should determine its size and distribution. The results of these surveys can then be used to assess whether more intense monitoring of the population is required. There are no guidelines as to the length of time between surveys but counts every five to ten years have been used to monitor some other endangered species (Green & Hirons 1991); given the lifespan of this species, population-wide surveys every 10 years may be sufficient. If the initial paired survey indicates that the number of breeding adults is not significantly less than the number of breeding age adults then the second part of the survey could be discontinued in future years.
All current and historical nesting locations should be surveyed, including all terrace levels along the coast between the Norris Point and Margaret Beaches (see Figure 1). Overall numbers of birds should be recorded, but nesting and/or display sites should also be mapped to show the most densely used areas. The first survey to count the number of breeding-age adults should be in January/February, during the peak period of male display, the second to count the number of breeding adults in June/July when the numbers of nesting birds peaks and nest attendance by adults is high.
Any differences in the distribution of birds between the two surveys may indicate areas which are favoured for nesting. Areas which are chosen by males for display purposes but are either shunned by females or fail early in the nesting attempt could indicate sub-optimum habitat which could be the focus of future management.
Currently the only practical method to survey frigatebird numbers is from the ground by counting adults on their nest or display site. Using ground-based surveys it should be possible to obtain reasonably accurate estimates of numbers in the golf course colony since access on foot is reasonably good. However, the upper terraces in the cemetery colony cannot be accessed on foot and numbers of nesting or displaying birds would have to be estimated based on observations of birds flying.
One full-time researcher would need to be employed for a period of 12 months and an assistant for at least 10 months. The first three months should be used to lay a grid on areas accessible by foot to facilitate later mapping of nest and display sites. This time could also be used to practice surveys and refine the survey technique. The first survey would take place in January/February followed by a two to three month period to analyse the data from these surveys and to prepare for the second survey. The second survey should be carried out in June/July and the resulting analysis and publication of results completed by the end of October.
If the total breeding population is significantly less than 1620 pairs then investigations should commence to reveal why. The decline may be explicable by the loss of breeding habitat in the Dryers colony and if this appears to be the case, there may be no need for other action. The monitoring program will suggest whether there has been significant loss of breeding habitat from the other colony areas, and if this is the case, investigations and strategies will need to be developed to try and reverse this loss of breeding habitat.
In the longer term, knowledge of where sub-adults and non-breeding adults forage is essential to allow planning for their long-term conservation in the face of inevitable, increased pressures on the marine resources of the north-east Indian Ocean. Seabird surveys in the Indian Ocean are carried out by a number of countries and the Recovery Team should support this work and facilitate its synthesis (see Cadee 1985, Dunlop et al. 1988, Ballance et al. 1997). The Recovery Team for both this species and Abbott’s Boobies should support the placement of suitable observers such as from the Australasian Seabird Group of Birds Australia or other vessels conducting surveys in the eastern Indian Ocean.
Specific Objective: 1. Maximising extent of occurrence and total population size.
Criteria: Breeding distribution of Christmas Island Frigatebirds maintained or increased on Stokes (1988) levels.
Action: 3. Monitor and/or assist the recovery of the Dryers breeding colony.
Monitor the recovery of the vegetation within dust affected areas. Dust affected areas need to be compared with unaffected areas. There are several possible methods of monitoring changes in the vegetation. One possibility is the use of some type of remote sensing technique such as the use of landsat images or aerial photography using a pixellated image. These techniques would require comparison with forest of a similar structure in a healthy condition. A colour scale which grades healthy to unhealthy trees would be used to assess the condition of the vegetation in the dryer’s colony. Alternatively, individual trees could be mapped and their health monitored using subjective measures recorded from the ground. The resulting monitoring program should be as simple as possible and only need checking a few times each year. Ideally it should be set-up so that a monitoring round only takes a few hours every few months permitting PANCI staff to carry out monitoring.
Christmas Island Frigatebirds: Any remaining nests which occur along the fringes of the dust affected areas need be monitored (if they are still obvious). Five nest trees occurring in this fringing zone were found and labelled in September 1994, however, this short survey was not comprehensive (A. Dunn unpubl. data). These trees would have to be located and mapped and should be checked each year for use and if birds return to nest to the north of these on the shore terrace the nest trees should also be mapped. The initial mapping of trees may take several days but once these are established it should only take a few hours to check for activity in the trees and along the shore terrace. Trees occurring near the dust affected areas on the shore terrace should be searched for breeding activity. The site would only need to be visited once or twice per year during the time of peak breeding activity in June/July. Monitoring should be kept up for at least five years with a re-assessment after this time to determine any further actions needed, unless birds are observed in this area.
Specific Objective: 1. Maximising extent of occurrence and total population size.
Criteria Protection of all habitat critical to survival of the Christmas Island Frigatebird.
Action 4. Development and implementation of a wildlife management plan for frigatebird habitat outside the national park.
Action 5. Ensure protection of habitat critical to survival outside the national park.
Most forested land outside the National Park is publicly owned by the Commonwealth. PAN staff on Christmas Island (and Darwin) are routinely involved with the other stakeholders in negotiations over development proposals. This is ongoing. These proposals can occur unexpectedly and as there is no overall wildlife management plan outside the park are assessed on an ad hoc basis. While consultation with other agencies and proponents on projects will be essential and ongoing (under the EPBC Act referrals process), achievement of long-term protection of threatened species outside the park requires a more comprehensive and considered approach through the development of a wildlife management program. The EPBC Regulations provide for the development of approved management programs to provide a more comprehensive protection regime outside the park. These plans can allow for the input of relevant landholders and decision makers, provide more strategic and comprehensive protection of flora and fauna while facilitating greater certainty for environmentally-sensitive developments.
The boundaries of all Christmas Island Frigatebird colony areas require re-mapping. Potential nesting habitat, and areas where nesting habitat might be re-established, should also be mapped. Any planned changes to land-use within 300m of nesting colonies should require examination under the EPBC Act referral process for potential impacts on Christmas Island Frigatebirds.
Specific Objective: 2. Implementing threat abatement strategies.
Criteria: Crazy Ants having an insignificant impact on Christmas Island Frigatebirds.
Action: 6. Implement the Invasive Ants on Christmas Island Action Plan.
Parks Australia North is currently implementing an Invasive Ant Action Plan, which aims to control and minimise the impact of Crazy Ants across the island. This program will require ongoing monitoring of Crazy Ant numbers and control of populations as detected.
Specific Objective: 2. Implement threat abatement strategies.
Criteria: Maintenance of effective quarantine against the introduction of avian diseases.
Action: 7. Maintenance [and regular review] of a quarantine barrier between Christmas Island and all other lands to minimise the risks of new avian diseases establishing on Christmas Island.
As part of the regular review process of the Christmas Island Quarantine Service, the effectiveness of the quarantine barrier preventing the man-made introduction of avian diseases onto Christmas Island should be assessed. Review of the Christmas Island Quarantine Service is undertaken by the Australian Quarantine Inspection Service with input from PAN.
Specific Objective: 3. Increasing community involvement in and awareness of the Frigatebird.
Criteria: Demonstrated increase in community awareness and support for habitat protection.
Action: 8. Conduct a community education program.
Most of the nesting habitat currently used by Christmas Island Frigatebirds is close to areas of high human activity. The Golf Course colony abuts the only golf course on the island, the cemetery colony is adjacent to an area proposed for residential and commercial development in the proposed Town Plan (Rumpff, H. pers. comm.). Community support for the conservation of Christmas Island Frigatebirds will greatly increase the likelihood that management of this threatened species will be successful.
As part of the Christmas Island Education and Interpretation Plan which has a key objective of increasing knowledge of and local support for habitat and species protection, this project may include production of a multi-lingual pamphlet on Christmas Island seabirds in general stressing their uniqueness and vulnerability. This could be accompanied by a curriculum unit on endemic seabirds for both primary and secondary school students. The costs of this program could be shared with the Abbott’s Booby and other Christmas Island threatened bird recovery plans.
Specific Objective: 4. To implement the Recovery Plan through a Recovery Team.
Criteria: Demonstrated successful operation of the Recovery Team over five years.
Actions: 9. Establish a recovery team which meets regularly