In search of a bell frog
As you would have gathered by now, this website has loads of posts and information about frogs, which I think is cool as they are fascinating creatures that are really suffering these days at the hands of so-called progress. So my search for wildlife led me to an interesting site in inner Melbourne that holds a population of unusual frogs that suffered some nasty declines in recent years… a species of “bell frog”
What is a bell frog?
Well, the name is misleading as none of these frogs make any kind of ringing sound nor are particularly bell-shaped but their exact classification status was debated for quite some time. Originally they were thought to be swamp frogs from the family Ranidae (typical Eurasian/North American/African frogs) as they looked so similar to many species in that family. But later research clearly put them in the tree frog family Hylidae (some say they belong in the Pelodryidae) due to cartilage in the fingers and toes and genetic relationships. They are all tentatively placed under the genus Litoria.
Today there are a number of species that fall into the “bell frog” category. They all live in vegetated swamps or slow flowing creeks, are medium to large and active predators.
Western Australia has two bell frog species, the motorbike frog (Litoria moorei) and the spotted thighed frog (Litoria cyclorhyncha) which live in the far southwest of that state.
Southeastern Australia has three species, the growling grass frog of the south (Litoria raniformis), the green and golden bell frog of the far coastal east and southeast (Litoria aurea) and the thought extinct but rediscovered yellow spotted or New England swamp frog (Litoria castanea) of the tablelands in northern and southern NSW and ACT. These three are all very similar and are distinguished by the following features:
- The growling grass frog (or warty bell frog) is distinguished by having both a bumpy back and blue thighs
- The green and golden bell frog has a smooth back and blue thighs
- The yellow spotted swamp frog has yellow spots in the thigh/groin area
These three species of bell frog are of particular interest as they are in the greatest decline and they are reputed to be almost super-predators of other frogs, allegedly tracking them down by their calls and devouring them!
The only other species that is often called a bell frog is the Dahl’s aquatic frog of the far north of Australia (Litoria dahlii). It shares many features such as general shape and habitat but it is also very different in many ways. The foot structure is quite different and although the most common frog of all in many Top End swamps almost nothing is known about it! Its call has never been recorded and it may only call for one or two nights a year. The details of the calling behaviour is also widely debated. I have personally seen them calling en mass on land around ponds with a repetitive yapping sound much like the related rocket frogs, but others say they have been witnessed sitting in the shallows and making a low frequency call or even signalling underwater! None of any of this behaviour has ever been recorded and their breeding habits, eggs etc are yet to be documented. Like other bell frog species, the Dahl’s is known to feed underwater at times.
Bell frog habitat
Most or all of the bell frog species have a few habitat preferences in common. These are the conditions I noticed with the species I have seen personally:
- Lots of vegetation, preferably emergent (reeds, bullrush, water ribbons)
- Water of reasonable clarity
- NO mosquito fish
- Permanent or semi-permanent water
Oddly enough some bell frog species seem to be highly tolerant of many kinds of pollutant! There are great populations in dumps that contain enough toxins to be lethal to other frogs!
For reasons unknown, one species, the green and golden bell frog has been introduced to Fiji, New Caledonia and New Zealand where they thrive!
To find a bell frog
I got interested in frogs a long time ago as a kid when we used to catch tiny eastern froglets and raise tadpoles. But I had never heard of our local bell frog species the growling grass frog as it was practically extinct in my region. I first heard of this species in early high school and a photo in the files of a local conservation area got me very keen. I talked to people, obtained permission to access land and generally looked everywhere, sometimes hearing a brief call or finding a tadpole in a swamp. But no sightings came until 2001 in a Victorian Frog Group meeting at Werribee Zoo just outside Melbourne. Gerry Marantelli (who looked like Gandalf from Lord of the Rings back then with his long beard) demonstrated how to fire up the local bell frog population by imitating the growling call. It worked and soon a male was calling back in a territorial sound battle. I managed to photograph one or two of these and finally I had reached my goal of actually seeing one in the wild! Soon after, I located a healthy population via a tip off from a ranger in my local area and recorded one calling at close range.
My first encounter with a green and golden bell frog was in far eastern Victoria at Thurra River estuary. I had arrived late at night looking for a place to camp and was greeted by dozens of growling calls coming from the reeds in the main river estuary. So I set out to try and find them but the reeds were too thick and access was impossible. The next night I found loads of them calling on the other side of the river in the swamp country. Males were half-floating in the shallow water, growling away.
But the most recent encounter was care of consultant and friend David DeAngelis who guided me to a spot in inner Melbourne full of these frogs. A stormwater creek surrounded in reeds was full of them. I could see the eye shine of dozens of them in the water, around the banks and high in the reeds. The water was clear but stank and the mud was black. Houses are all around this site but the frogs seem to be thriving – so long as mosquito fish continue to be excluded.
Bell frog species in the southeast of Australia may be suffering great declines, but with the creation of simple habitats among our own there may yet be hope.
To see a video of a green and golden bell frog calling, see below…
Like the pictures? Try the Canon EOS 60D. Lens used was the Canon EF-S60mm f2.8 USM with twin Speedlite flashes in wireless configuration.