Strathbogie Trailcams

The Strathbogie Forest Citizen Science program comprises a variety of activities, including camera trapping. Use of trailcams which sense heat and motion is now one of the got-to techniques in wildlife survey. Over the last four years we’ve been surveying the terrestrial mammals of the Strathbogie Forest and have set camera traps at 66 different sites.

Full report available soon.

An Island Forest

The Strathbogie State Forest is an island forest, surrounded on all sides by farmland and separated from similar mountainous country to the east and south by the valleys of the Broken and Goulburn Rivers. It comprises a variety of habitats and vegetation types, but predominantly Herb-rich Foothill Forest (or Peppermint-Gum Forest) characterised by Manna Gum, Mountain Gum, Messmate and Victorian Blue Gum and Grassy Dry Forest.

Trailcam Equipment

Trailcams (without lures) were used to survey ground dwelling mammals. Community volunteers helped to deploy the cameras and to assess the still and video recordings.

To our knowledge there has been no systematic surveying of ground dwelling mammals in the Strathbogie Forest since the 1980s (which used Eliot and cage trapping) and this project is the first coordinated trailcam survey in the forest.

Most of the sites (91%) were surveyed using Bushnell Trophycams (17 cameras, various models); 9% were surveyed using Reconyx Hyperfire (3 cameras HC600). Trailcams were usually fixed to trees and set approximately 1 m above ground level. A variety of trailcam settings were used and the cams recorded either video or still images.

Site Selection & Set-up

Selecting the location to set-up your trailcam is the final step in the process. Minimizing false-triggers is one of the ‘must-dos’ of camera trapping. Swaying leaves, of shrubs, trees or grass can trigger your trailcam to record, giving you reams of unwanted stills or video to wade through and unnecessarily filling the SD card. Some prudent positioning, walk testing and pruning can help reduce false-triggers.

The height you place your camera depends on your target species and also the size of the field of view you want to monitor. In our case we generally set the camera about a meter off the ground and pointing slightly to the ground. Some cameras were set low to the ground under the shrub canopy, to better detect smaller species like rats and Antechinus.

Demonstration Sites

Putting principles into action, we describe setting up trailcams at three different sites in the Strathbogie Forest.

What Did We Discover?

Camera trapping detected 19 mammal taxa including 12 native species, five introduced species and two unidentified species (Antechinus sp. and Rattus sp.).

Results of Strathbogie Forest trailcam surveys: 50 sites, 4094 camera trap-days. This table will be updated as additional trap-site data becomes available.

The most commonly detected species were Black Wallaby, Red Fox, Mountain Brushtail Possum, Common Wombat, Sambar Deer, Feral Cat, Koala, Eastern Grey Kangaroo, Short-Beaked Echidna, Eastern Ringtail Possum. Species detected at less than 20% of sites were Antechinus (most likely A. agilis), unidentified Rat, Rabbit, Long-nosed Bandicoot, Common Brushtail Possum, Bush Rat, Black Rat and Sugar Glider.

Conclusions drawn about individual species will be integrated into the Mammal species descriptions, but some particular observations are relevant here.

Though this survey recorded a wide variety of mammals species, from the 25 g Agile Antechinus to the 150+ kg Sambar Deer, generally our trailcam site selection probably favoured detection of larger mammals like macropods, Common Wombat and Koala that readily traverse open spaces and are more readily detected by the trailcams. Conclusions about the distribution (and abundance) of smaller species like Antechinus, rats and bandicoots are less robust.

It was exciting to confirm the presence of Long-nosed Bandicoot at several sites in the forest, though the small number of detections suggests the population is small and dispersed. We failed to detect several species previously recorded in the Strathbogie Forest: Spot-tailed Quoll, Brush-tailed Phascogale and Eastern Pygmy-possum. The lack of quoll detections was expected and our results give weight to the likelihood they are now locally extinct in the Strathbogie Forest. The absence of phascogale records is harder to interpret, as the species’ presence is well documented in areas surrounding the forest, including in similar habitat and vegetation types. It’s possible that additional camera trap surveys would detect the species, but a total lack of any records of the species in the state forest, in either the VBA, ALA or iNaturalist suggests they may be absent or occur at very low densities.

The presence of feral species, Red Fox, Feral Cat and deer is concerning. The ecological impact of foxes and cats on native animals is well established and may account in part for the small number of bandicoot detections from the survey. Whilst Feral Cat was detected at far fewer sites than Red Fox, a number of trailcam sites detected several individual cats utilizing an area, suggesting that they have overlapping home ranges. Deer, both Sambar and Fallow, occur in the forest. Sambar occur in large numbers and were recorded at a majority of trail cam sites. Our camera trapping detected Fallow Deer at multiple sites in the drier northern parts of the forest. They were also incidentally observed in pine plantation near Police Tk, but are generally absent from the wetter, central and southern parts of the forest. Sambar on the other hand were detected in all forest types. No Wild Dogs were detected by the trailcam surveys, but a Feral Pig was detected at a single site on Lightning Ridge Tk.

For more trailcam footage from our project:

File and data management

For purely survey and file management purposes images are preferable to videos. Trigger time is generally much faster for images, less memory is required (in the camera and for storage) and review time is much faster. However, for education and engagement, video of animal behaviour is far superior to images – for experts and community alike. Video can also improve species identification by picking up subtle movements that images miss. For example, it would be hard to replicate the learning and engagement enabled by these videos of Black Wallaby, if only recording still images.

Hints

A simple way to quickly review large numbers of images, using a PC running Windows, is to disable the ‘Preview pane’ and ‘Navigation pane’ (in the View tab), select ‘Extra large icons’ and expand the File Explorer window to full-screen. This allows you to scroll through many images quickly and is very useful when there are hundreds of false triggers.
If you’re particularly interested in small animals that inhabit dense vegetation, place trailcams right inside those places, rather than in gaps around or between that habitat. You may lose some field of view and detection range, but you’ll have confidence you’re sampling the habitat where the animals live.
Efficient use of trailcam batteries, memory and your time is largely a result of reducing false triggers. The video presentation covers vegetation triggers and strong shadows are mentioned. Shadows, silhouettes and strong light all produced false triggers in our surveys. Avoid open sites with sparse or no canopy but where defined shadows cross the field of view e.g. tree trunks, branches and canopy foliage. Face the trailcam to avoid the sun directly hitting the camera lens. Some false triggers are inevitable, but these tips will help.

File management software

There are several software packages available to improve management of large volumes of images and some of these also handle videos.

One thought on “Strathbogie Trailcams”

Michael Bankes says:

May 19, 2021 at 8:58 am

Thank you Bertram for this insightful program. I will continue my surveys now with greater enthusiasm.