I have found frogs to be one of the most frustrating of animals to identify and it has taken several years to come to terms with my local species. One of the greatest difficulties is with the huge variation of color and markings that a single species can attain. In most instances here, I have provided several photographs of individual frogs of the same species to illustrate the variations and have also tried to include very young frogs for comparison. However, the variations shown do not represent all varieties that can be easily found, so please read the text carefully and compare with frogs in the links provided, as identification can be a great deal more complicated and confusing than you would think from initial observation.
The easiest method to identify frogs is by their call, which are quite distinctive and many froggy people will just go on these to work out the frogs in a particular area. However, to do this you need a very good ear and a musical memory to recognise the calls of specific species and not be confused with other frog calls. Sounds easy until you try and from my experiences not something quickly mastered. I would suggest you memorise one call at a time until you can recognise it instantly, then move onto the call of another species in your area.
The frogs in the Esperance district do not seem to be affected by the chytrid fungus that is decimating frog species around the globe, although I suspect they are appearing more often in the diet of foxes, particularly during autumn/winter when other foods are less available. There is very little permanent water in the local sandy soils; instead there are many small ephemeral swamps that fill after good rain, then to slowly drain away through the sand that overlie a clay substrate. If it remains dry, or if the rain is insufficient and the swamps dry too quickly, then the frogs cannot successfully breed or their tadpoles survive, so this climatic aspect coupled with fox predation, can swing frog numbers from being numerous to being far less so.