In 2024, the Orange-bellied Parrot (OBP) Tasmania Program completed its first year of a two-year migration tracking project to track OBPs during their annual migration. This early work is helping to understand more about timing, flight path and risks to OBPs during migration and has been funded by the Tasmanian Government. The data shown here accompanies the 2024 Interim Report on the results of the first year of VHF tracking. The report is available from the Department of Natural Resources and Environment Tasmania website.
In the first year of tracking, 46 VHF transmitters were attached to OBPs over late February early March and data recorded at 18 VHF receivers deployed across the migration flyway within Tasmania to detect birds on their migration. A total of 12 of these birds were detected across Tasmania following their departure from Melaleuca breeding grounds.
The results of this project revealed nocturnal flight was an important aspect of OBP travel over long distance migratory legs between breeding grounds and stopover sites and over-wintering grounds within Tasmania, and between stopover sites in Tasmania and over-wintering grounds on mainland Australia. In 2024, juvenile OBPs primarily transited the west coast of Tasmania in a single flight, undertaking these flights over the first two weeks of April. Across the northwest of Tasmania and adjacent islands, and on King Island juvenile OBPs utilised various habitats including pasture, saltmarsh and heathland from early April through to the end of tracking in late May and early June.
VHF tracking technology does not provide spatially-explicit data and instead location has to be estimated using signal strength of received radio transmissions from trackers as a proxy for distance and direction from a receiver antenna. This method cannot refine location accuracy of a detection to less than +/-2km. Further, caution should be taken when generalising the findings of this season's work to the entire OBP population due to the small sample of birds tracked this season and that nearly all tracked birds (45 of the 46 birds) and all those detected outside of Melaleuca were juvenile OBPs. Juvenile and adult OBPs have different migration ecologies particularly in regard to timing of migration and survival rates and therefore the findings of this year's survey have little congruity with migration behaviour of the adult population. Interannual variation in juvenile migration trajectories and departure dates due to differences in environmental conditions year-to-year is also not captured in this one year of surveying and is a limitation of the findings of this report.
https://nre.tas.gov.au/conservation/threatened-species-and-communities/lists-of-threatened-species/threatened-species-vertebrates/orange-bellied-parrot/the-obp-tasmanian-program
