Breeding populations of Southern Giant Petrels at Heard Island, the McDonald Islands and within the AAT

This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION The breeding population of Southern Giant Petrels is related to resource availability (nesting space and food), behavioural mechanisms (immigration/emigration and breeding effort/success) in addition to climate change and human impacts (including fisheries and human disturbance). Monitoring breeding populations and interpretation of the data provides information on changes in the Antarctic and Subantarctic ecosystems.

DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial scale: Colonies near Australian Stations - Frazier Islands, Casey (lat 66 degrees 16' 54.5' S, long 110 degrees 31' 39.4' E) Hawker Island, Davis (lat 68 degrees 34' 35.8' S, long 77 degrees 58' 02.6' E) Giganteus Island, Mawson (lat 67 degrees 36' 09.7' S, long 62 degrees 52' 25.7' E) Heard Island - (lat 53 degrees 06' 00.0' S, long 73 degrees 31' 59.9' E) McDonald Islands - (lat 53 degrees 02' 26.2' S, long 72 degrees 36' 00.0' E) Frequency: Breeding Southern Giant Petrels are easily disturbed.

Colonies are visited every 3-5 years to minimise disturbance to breeding birds. Measurement technique: All colonies are visited and breeding birds are counted from outside the colonies by two personnel performing replicate counts. All breeding individuals in a colony are counted.

No birds are disturbed off their nests. Considerations regarding disturbance associated with census visits are also incorporated into monitoring strategies. The lack of annual census data does not reduce the value of these long-term monitoring programmes.

RESEARCH ISSUES All Southern Giant Petrel breeding populations in the AAT and at HIMI decreased following their discovery. Southern Giant Petrels breeding on Indian Ocean islands are highly sensitive to human disturbance. Access to breeding colonies is restricted, as are the types of activities permitted.

Disturbance from researchers has been implicated in the observed decreases in these populations (Woehler et al. 2001, Woehler et al. in press). Analyses of the long term AAT data suggest that the breeding populations at Hawker Is and at the Frazier Is have recovered following the restrictions on access and activities permitted on breeding islands. LINKS TO OTHER INDICATORS