The upland chorus frog spends its days hiding in damp places (2) (3) such as under logs or within grass tussocks, emerging at night to find food (3). Although this species feeds throughout the year, it may do so less in the winter, and males tend not to feed at all during the breeding season (2).
Adult upland chorus frogs are sit-and-wait predators (2) with a diet that varies seasonally depending upon the prey available (2) (5). Generally feeding on anything it can within about one metre of its location (2), the upland chorus frog eats spiders, snails, caterpillars and a variety of insects, including beetles, ants and flies (2) (4) (5). Upland chorus frog tadpoles feed on detritus found within the mud on the bottom of their habitat (2) and on algae scraped from plant stems and other underwater objects (4).
Predators of upland chorus frog tadpoles are numerous, and include invertebrates, such as beetles, dragonfly larvae and spiders (2) (3) (4) (5), as well as newts, snakes and fish (2) (3). Adult upland chorus frogs are predated by a variety of fish, birds, water snakes, turtles and small or medium-sized mammals (2) (4) (5). It is thought that the upland chorus frog avoids contact with certain predators such as fish by breeding in temporary pools (5), but if approached by a predator, this species stays completely still and relies on camouflage to keep itself hidden (3). Upland chorus frog tadpoles are rapid swimmers, but if they come into contact with an object their defence is to suddenly stop swimming and sink motionlessly to the bottom of their habitat (2).
Interestingly, in addition to using the calls of other individuals as auditory cues, adult upland chorus frogs are thought to use the sun to help orientate themselves on migration to find their way to breeding sites (2). This species is capable of travelling some distance over land (2), and although breeding generally does not begin until late winter or the spring (2) (3) (6) (7), upland chorus frogs tend to start gathering at breeding sites during the autumn (2). In some parts of its range, the upland chorus frog is the first amphibian to be heard calling each year (2) (7), and is viewed by many to be a signal that spring is on its way (6). The exact timing of breeding is variable throughout the range of this species, and depends on the location, as well as on environmental conditions and the type of breeding site (2).
The upland chorus frog tends to select breeding sites containing warmer water, as this helps the larvae to develop quickly. At these sites, male frogs usually begin chorusing several days before breeding begins (2), perching together in large numbers on the edge of the water (6). Male upland chorus frogs may also call from the water (6), either in the shallows on the edge or floating with their rear legs out behind the body and with the head poking out of the water to expose the balloon-like vocal sac (2). Calling occurs throughout the day (2), particularly on overcast days (7), but during the peak of the breeding season the male upland chorus frog may call day and night to attract a mate (3). The male frogs remain in the breeding pools for several weeks to compete for mates, whereas the females tend to migrate to the area for short periods, returning to their terrestrial habitats once they have laid their eggs (3).
The female upland chorus frog moves towards an attractive calling male, and eventually will position herself in front of the male before making contact by touching him (2). At this point, the male immediately stops calling (2) and grasps the female from behind in amplexus (2) (7). In this position, the male fertilises the eggs as the female lays them (2). The female upland chorus frog lays several separate clusters of eggs (2) (3) (7) over the course of several days (2). Clutch sizes vary greatly, and have been reported to range from just 10 eggs to more than 500 (2), with females capable of laying up to 1,500 eggs in one breeding season (2) (7). Large female upland chorus frogs tend to produce more eggs than smaller females (2). The eggs are laid in small, elongate clusters which are attached to sticks, grass stems and other underwater items (1) (2) (3) (4) (6) (7) just below the surface (2) (4).
Upland chorus frog eggs hatch within a couple of weeks (2) (3) (4) (7), although hatching may take longer the cooler the water is (4). Metamorphosis is also dependent upon environmental conditions (3), but generally the tadpoles transform into adult frogs after about two months or more (2) (3) (4) (6) (7). The young adult frogs are thought to stay close to their watery habitat for a short time (4), before dispersing to surrounding fields and woods (3). Most upland chorus frogs reach sexual maturity within their first year (3), with males starting to breed at about eight to ten months of age, although females may not breed until their second year (2).