Although they are not often seen by visitors, feral and domestic cats are established predators at Tarra-Bulga National Park and our remote camera results suggest they are becoming more common.
The table below shows results from five years of remote camera monitoring carried out by the Friends of Tarra-Bulga Park. Cat numbers as a percentage of total species recorded rose dramatically from 0.7 to 3.9%.
|No. of Cats Records||16||33||64||59||41||64|
|Percentage of Cats||0.7%||1.1%||1.3%||1.6%||3.0%||3.9%|
The impact these cats are having on the birds, small mammals and reptiles is a real concern. Although there are many variables in the ways we set up our cameras, the general trend in the last few years is for them to be detecting greater numbers of cats and less small native mammals (e.g. Antechinus and Bush Rats). Sadly we have also been detecting less of the smaller birds such as Pilotbirds and White-browed Scrubwrens. (For a summary of sightings of others species download this Percentage of sightings per year for commonly detected species captured in remote camera photos )
The gallery below shows that cats in Tarra-Bulga range from large ferals and panther look-alikes to small (some might say cute) looking kittens, some even have collars. What is undeniable though, is that their presence has a major impact on the ecology of Tarra-Bulga National Park.
Overall total number of species sightings – all cameras
|Common Brushtail Possum||75||13||0||5|
|Eastern Yellow Robin||3||4||11||12|
|Large Billed Scrubwren||0||0||0||2|
|Long Nosed Bandicoot||287||119||270||652|
|Mountain Brushtail Possum||181||235||243||289|
|White Throated Tree-creeper||0||0||4||3|
Without any advanced statistical scrutiny strong trends include:Our remote camera monitoring has now reached four solid years of records. Although not a flawless scientifically planned project there are still be some interesting developments. The table above shows the total sightings of each species combined across all of the camera sites. There are many variables in these results, the main one being that cameras have been moved around different habitats at different times, so have not constantly been in the one place.
- A massive rise in the number of Brush Bronzewings every year.
- A rise in the number of other ground dwelling bird species including Bassian Thrushes, Pilotbirds, Eastern Whipbirds and Common Blackbirds.
- An increase in the number of Long-nosed Bandicoots (although this may be explained by moving cameras to areas where habitat is more suitable).
- Crimson Rosellas had a huge spike in numbers in 2014 (maybe because there was a lot of wattle seed on the ground?)
- An upward trend in Echidna and Feral Cat numbers.
- A drop in Fox numbers in 2015.
- 2014 had double the amount of Lyrebird sightings than other years.
Several cameras have been left in the same spot for several years and it is possible to compare the results of these sites with the overall figures.
Site: Tarra Bulga – North East
Habitat: Mountain Ash forest with an open understorey consisting of scattered shrubs, ferns and grasses:
|Eastern Yellow Robin||0||1||2|
|Long Nosed Bandicoot||38||13||8|
|Mountain Brushtail Possum||8||10||16|
|White Throated Tree-creeper||0||0||2|
Site: West of Balook
Habitat – Forest with an open understorey, canopy consists of mature Silver Wattle.
|Eastern Yellow Robin||0||1||2|
|Long Nosed Bandicoot||17||0||3|
|Mountain Brushtail Possum||46||11||7|
|White Throated Tree-creeper||0||1||0|
Comments: The open nature of this site means it is less suited to small mammals. Popular site for Swamp Wallabies to congregate. Openness also suits many ground feeding birds scratching around or eating fallen seeds. Foxes and cats often pass through. Has been a Koala habitually passing the camera every few days between its favourite trees.
Site: Balook Area
Habitat: Open forest with regenerating Mountain Ash, Ferny understorey with some thick scrubby patches near by.
|Eastern Yellow Robin||0||4||3|
|Long Nosed Bandicoot||6||149||168|
|Mountain Brushtail Possum||95||73||79|
Comment: Good site for a diversity of species, some scrubby ground-cover in the area makes it a good spot for Bandicoots, with a high proportion of our Bandicoots sightings recorded here. Also good for introduced Common Blackbirds and Rabbits that like to hide in cover. Like other sites had a big spike in Crimson Rosella numbers in 2014. Interestingly large drop in Fox numbers.
A recent post reporting on the results of our camera trap monitoring program for 2013, identified a trend with Swamp Wallabies where numbers photographed by across the park by camera traps dropped very sharply after July. We have no real explanation for this, but as we gather further data, it will be interested to see large annual fluctuations in the Wallaby count continues.
We had an inquiry as to whether it was more common to record Swamp Wallabies in daylight or during the night-time, which is an interesting question and one which is easy to work out from our database. So after crunching some numbers here are some answers, not just for Swamp Wallabies, but for all our commonly recorded species.
Swamp Wallaby triggers are fairly regular at any time of day or night, they do seem to slow down as you might predict in the middle of the day, but then fire up to have their peak numbers in the early evening.
Although it is not particularly uncommon to see Wombats out during the day sometimes, perhaps surprisingly we have never had one trigger a camera between 8am to 4pm. They seem to have peak activity in the evening and another peak around 4am.
It’s no surprise that these Bandicoots are rarely seen, although we get fairly regular photos of them, they seem to have a definite peak of activity between 2am and 4am.
The graph shows here that there is never any time of day for animals to be complacent. Foxes can be active at any time of day, seems like they are marginally more common at night. Also have data on Feral Cats, they too can be around at all hours, but seem less likely than a Fox to be around in daylight.
Lyrebirds in Tarra-Bulga obviously need to make the most of the daylight hours. It seems there is a slightly greater chance they will be snapped by a camera in the morning, but overall any time of the day is good for them.
2013 Remote Camera Stats
Camera Site Greatly Exceeds Expectations