A Mammal Action Plan reflecting contributions from over 200 scientists is to be launched by the Federal Environment Minister in July. It calls for decisive, radical intervention to halt and reverse native mammal decline in Australia.
From the authors: "If we had to choose one wish for advancing the conservation of Australia's biodiversity, it would be the effective control, indeed eradication, of cats. It is not an impossible task".
The Plan is said to represent a resounding call to arms for federal and state governments which to date have failed to invest adequately in feral cat control. It will no doubt be of great interest to many BIBY members. When it comes to feral cats, what applies to our native mammals also applies to our native birds.
Nice to hear, Night Parrot. Looks like no more coal mines will be approved in Australia. Beauty!!!!
I fully agree that it's not an impossible task to eradicate cats from Australia. It's a question of values rather than a question of know-how or resources in my opinion.
At least with mammals, it sounds like good things are starting to happen. I read an article a few eeks ao where the NSW state government was planning to start working with Australian WIldlife Conservancy to reintroduce some long locally extinct mammals into feral free enclosures in half a donzen NSW national parks with the goal of eventually reintroducing them into the parks as a whole.
Yes Woko and Lachlan its good to see something positive going on. The Australian Wildlife Conservancy (AWC) does some really great work. It seems the only practical way to go; fence off a large area, get rid of all the ferals in that area and then introduce endangered native animals that can live and thrive as they could in the "old days" before Australia "lost the great populations of unique mammals that once filled our landscapes" (AWC).
Interesting comment from Lachlan that government is working with AWC. And rightly so. Prof Tim Flannery has been quoted as saying that most of our national parks are now marsupial ghost towns.
I agree that cats and foxes have been a major cause of mammal decline in Australia, and eradicating them would be a great outcome and worth the expense. When it comes to birds I think most species aren't impacted in a major way, apart from small ground dwelling birds. Australian birds evolved with predators such as quolls and snakes and are pretty good at keeping away from cats, though I would be interested to see research that says otherwise. Also the energy gain from eating birds is less for feral cats so they concentrate more on mammals and reptiles.
I think that habitat loss is a much bigger problem for birds. At my place I dpn't worry about ferals, but I don't keep stock in an area that has been continually grazed for 150 years, and the numbers and variety of birds is always increasing. I think destocking marginal farmland has a more beneficial effect for native birds than eradicating ferals.
You are probably right about habitat loss Greg but I would be surprised if feral cats were not having a major impact on birds. They are probably in their millions and they can climb trees and/or lie in ambush to catch all kinds of birds. They are efficient hunters and even domestic cats can make a killing in the suburban backyard. But I am no expert and I don't know the research on this. Certainly AWC seems to concentrate on the mammals; presumably because they are more susceptible.
Domestic cats kill a lot of birds because they don't have to worry about energy expenditure and net energy gain. Life is very hard for feral cats in the bush and they can't afford the energy expenditure of hunting birds for such a small reward, the reward for killing mammals is much larger.
Hmm, I'd view it the other way around Greg, and suggest that domestic cats have less opportunities to predate birds, while ferals have to subsist on what they can kill.
There's been studies done on the behavioural evolution of crab predation of periwinkles (hey, it's interesting and relevant!). The crabs have evolved to maximise energy gain from each periwinkle. The larger ones are harder to crack, but provide more food, while the can crack more small one, but get less food from each. So, I guess cats (and any other feral) would probably concentrate on certain sized prey, based upon how much effort and gain they can get from it. It would be interest to know where exactly small marsupials and birds sit in comparison to eachother. I think it would be hard to test though, there are so many variables, and the method of the crab-periwinkle experiment would be shot down by animal rights people (and probably rightly so). They basically provided the crabs with an excess of mixed (but quantified) periwinkle sizes, and then examined which one were eaten the most. Not gonna happen with native wildlife!
Hi Greg. We've had a number of cat advents on our place. Around two of them Superb Fairy-wren numbers dropped from between 30 & 40 to about 10. Around each of the others there was usually a decline in Fairy-wren numbers but not as significant as the two large declines. No increase in Fairy-wren numbers seems to have been associated with cat advents. The evidence is building that cats are not good for Superb Fairy-wrens, at least at our place.
I agree Greg, our birds evolved alongside quolls so have some capacity to withstand population predation pressure from mammalian sources.. though i don't doubt there is some level of impact at least on vulnerable species, though perhaps a lesser threat than habitat destruction. I think this can be contrasted with the situation on many small isolated oceanic islands which had no native mammal predators, the avifauna on many was practically wiped out following the introduction of predators as the birds had no defensive instincts.
Woko, I don't know what method you use for fairy wren counting. They move around a lot and may move to new territory according to food availability. I sometimes have feral cats around, I haven't noticed any effect on fairy wren numbers, maybe because I allow lots of weeds to grow which provide cover for the wrens. Currawongs and butcher birds are probably the main predators of small birds at my place. Also they are parasitised by cuckoos.
Hi Greg. I walk at least once per week the length of our property & back again & make note of the maximum number of birds I see each week. At the end of each year I average the maximum weekly numbers for each month of the year, enter this data into a spread sheet & produce graphs of population trends.
Yes, the Superb Fairy-wrens do move around but there are also particular locations where they're commonly seen. There is certainly heaps of cover for them with weeds, native grasses, low & medium shrubs, fallen trees all providing protection. There are also deliberately planned open areas in which they forage.
We get occasional visits from a Grey Currawong or two but only one observation of a Pied Butcherbird in the 27 years we've been living here. So predation from other birds isn't an issue. I suspect Horsfield's Bronze Cuckoos may have laid an egg or two in Superb Fairy-wren nests but I have no direct evidence of this.
This is a shot of an area where I've been doing minimum disturbance bushcare. Native grasses & Vittadinias, a native daisy, are making a strong comeback. Superb Fairy-wrens are often in this area & nearby.