The Waratah Wetlands is a great spot to hear frogs – and we are beginning to hear them more often around the Billabong too. Some species can be heard along the creek in other places as well. When ready for breeding, adult male frogs call. Each frog species has a distinctive call so that only females of the same species respond.
The common varieties of frogs we have in the Creeklands are:
- Eastern Banjo Frog or Pobblebonk (Limnodynastes dumerilii)
The frog’s common names come from its calls – pobblebonk after the distinctive “bonk” call of the males, which has also been likened to a banjo string being plucked. It is a common burrowing frog which may often be found in large numbers at night, especially after rain. It is a large frog – 70-80mm long with dark warty backs. As you might expect, its feet are adapted for digging. Males call from a concealed spot in water from spring to autumn.
- Spotted Marsh Frog (Limnodynastes tasmaniensis)
The Spotted Marsh Frog Limnodynastes tasmaniensis lives in shallow water with a cover of emergent vegetation such as found in swamps and ponds. This frog is smaller than its striped relative (below) – it grows to 45 mm in length. Its colour ranges from light brown to olive-green, with large, irregularly shaped, green or brown spots or blotches on its back. Usually, it has a thin pale cream, yellow or bright orange stripe running down its back. While floating in water, usually hidden in floating vegetation, the male makes a “click” or “tock” call – like two creek stones being hit together.
- Striped Marsh Frog or Brown-Striped Frog (Limnodynastes peronii)
This wetland-dwelling frog is usually light or dark brown with distinct darker stripes running down the frogs back (giving this species it name), normally a paler mid-dorsal stripe and with a white belly. The throat of males is yellow in colour. It is also quite a large frog – females may reach a length of 75 mm and males 70 mm. Breeding males develop thick arms useful in “wrestling” matches with other frogs for breeding rights. It is most commonly associated with wetlands and permanent water and shelters among reeds and other debris. It makes a “tock” or “pock” call – deeper than the Spotted Marsh Frog.
- Southern Brown Tree Frog (Litoria ewingi)
A widespread and common species often found in large numbers in flooded grassland or marshy areas. This great climber and jumper is reputed to be able to leap to catch a fly in mid-flight! This frog is smaller – growing to 45 mm in length. It is pale to dark brown on its back and the backs of its thighs are orange. It has sucker feet to aid in climbing and sounds a little like a cricket chirruping when calling.
The Frogs Australia web site has further information including recorded calls for each species – click the links below for access:
Frogs in Decline?
Frogs are commonly held to be strong indicators of the health of an environment. Sadly, frogs and tadpoles seem to be less common in Melbourne as some species seem to be fast dwindling in number.
These trends underscore the importance of our preserving and rehabilitating suitable environments, such as the Waratah Wetlands and The Billabong, for our amphibian friends.
Probably following from the increasing urbanisation of Blackburn, two species recorded in 1972 along the creek no longer seem to be present: the Victorian Smooth Froglet Geocrinia victoriana and the Common Froglet Crinia signifera – even though the latter is still common in other parts of Melbourne. On the other hand, the Striped Marsh Frog was not recorded in 1972 – so it has probably migrated in along the Corridor since.
The Waratah wetlands were restored in 1987-88 to hold more water over a longer period of time and that allowed aquatic vegetation to become more abundant – altogether a more favourable habitat for frogs. Maybe the Striped Marsh Frog needed that sort of environment to thrive in our park? Interestingly, the Frogs Australia website says this about the Striped Marsh Frog:
a large wetland-dwelling frog and voracious hunter, this frog eats almost any animal smaller than itself, including small frogs.
Perhaps that explains why there are no froglets these days???