When was the 2024 survey performed?
The survey was conducted between 2 - 17 October 2024. The 2019 survey occurred between 23 September - 4 October.
Who conducted the aerial survey?
The consultants used for the 2024 survey were the same as in 2019 – this ensured the methodology is consistent and the results are comparable.
Was the same method used in 2024 as in 2019?
Yes
What methods was used to estimate deer numbers?
Information collected during the aerial survey was analysed using a technique called Distance Sampling. This method is widely used internationally for the estimation of wildlife populations, including northern hemisphere deer populations; hoofed animal populations in Europe, America and Africa; kangaroos, camels and wild horses in Australia; and whale populations worldwide.
How was the survey conducted?
The survey is performed by a helicopter flown along transects spaced 10 km apart, at a height of 61 m (200 feet), at a speed of 50 knots (92 km/h). Each transect is flown once, so there will only be a single pass over any property. Surveys will be conducted within four hours following first light, and three hours prior to last light, subject to flying conditions and animal activity.
What information did the survey produce?
The 2024 survey produced an estimate of the population, species distribution and abundance within the survey area – this information can then be compared to the 2019 findings. Changes in distribution and abundance can then be considered in relation to deer policy such as licensing and permits to measure the effectiveness of deer management.
There are two reports presenting the results prepared by the consultants: the overarching technical report and a summary report.
Was thermal technology used in the survey?
During the aerial survey with observers in a helicopter, a simultaneous survey using thermal imaging camera was trialled for comparison with the aerial observer estimates of fallow deer from the same flight.
A separate report is available on the use of thermal technology.
Why was the thermal survey results not used to estimate the population size?
The thermal survey was only used as a trial to improve development of the technology.
Aerial survey with human observers is currently more cost effective than thermal surveys.
There are limitations to the use f thermal camera's such as - the field of view is less compared to human observers, and does not detect animals that move (get flushed) out of sight/view of the camera in response to the presence of aircraft. Human observers have a greater field of view and can count these animals.
Why was thermal survey not conducted for Forester kangaroo?
The thermal technique was only used for deer as Tasmania only has one species (fallow deer). thermal imaging cannot identify between species that have similar shape and size (i.e. cannot distinguish between Forester kangaroo, Bennett's wallaby and Pademelon).
Why did you need to survey wild Fallow deer and Forester kangaroo?
In response to the Legislative Council Inquiry into Wild Fallow Deer, the Government committed to undertake an initial baseline aerial survey of the deer population in 2019. The Tasmanian Wild Fallow Deer Management Plan 2022-2027 (the Plan) committed to a follow-up aerial survey, recognising that effective deer management requires an understanding of how a population changes over time. The follow up survey was conducted in 2024.
Why does the survey include Forester kangaroo – isn’t the survey about deer?
Forester kangaroo numbers are assessed every few years via walked transect surveys. The 2019 and 2024 aerial survey included Forester kangaroo and proved to be an effective and efficient means of estimating the population – this method is used frequently on the mainland.
Data from both survey methodologies will be used to inform sustainable management of the species, in particular how many can be taken and from where.
Why does the survey not include Bennett’s wallaby and Pademelon?
The survey uses a combination of human observers, thermal cameras and artificial intelligence to detect and identify animals. Using these technologies, Forester kangaroo are readily identified along with deer due to the size and shape, however smaller animals such as Bennett’s wallaby and Pademelon can be more difficult to distinguish, meaning the data is less accurate and therefore not captured.