The breeding ecology and phenology of two sympatric stream breeding myobatrachid frogs were studied across a breeding season in a stream at Cunningham's Gap, south-east Queensland. Mixophyes fleayi is listed as endangered and M. fasciolatus is considered not threatened. The two species occur sympatrically and their breeding seasons overlap, but they prefer different habitats for breeding and are markedly different in their reproductive ecology. Males of M. fleayi formed dense chorusing aggregations in shallow stony riffles of their rainforest stream.The number of individuals comprising the chorus was highly variable and related significantly to ambient temperature and stream height which, with rainfall, humidity and wind intensity accounted for 96.9% of the variation. Male M. fasciolatus did not show similar aggregation and called from more dispersed locations. The number of M. fasciolatus sighted on any given night showed no correlation with any of the assessed environmental variables.
Mixophyes fleayi appeared to have particular and specialised environmental and habitat requirements for breeding whereas M. fasciolatus appeared to be more of a generalist in its reproductive requirements. These differences afforded an opportunity to explore how a species' behavioural and ecological traits may provide resilience to population declines due to climate or habitat alterations.