(to either green or brown) during development. Their undersides are initially dark, but later become lighter in hue. The eggs are brown and are wrapped in a clear jelly; they are in diameter. The call is a low, slow , repeated many times. For most of the year, the frogs call from high positions, such as trees and gutters, but during the breeding season, they descend to near the ponds and pools, where they breed. Like many frogs, green tree frogs call not only to attract a mate, but also to advertise their location outside the mating season. They are particularly vocal after rain, but the reasons for this are unclear. They emit a stress call when they are in danger, such as when being attacked by a predator or when a person steps on the log in which one is concealed. Distribution and habitat The green tree frog is native to northern and eastern regions of Australia and to the lowlands of New Guinea. Distribution is limited mostly to areas with warm, wet tropical climates. Its range spans from Irian Jaya to Port Moresby, and is most abundant on Daru Island. The IUCN suggests "scattered locations" in both New Guinea and Indonesia. In Australia, its range extends from the Kimberley region of Western Australia through the Northern Territory and Queensland to north and central New South Wales and the extreme northeasterly part of South Australia. Its total extent of land occupancy is around . The species has been introduced to both the United States and New Zealand. In the United States, it is restricted to two regions within Florida, where it was possibly introduced through the pet trade. Only small populations have been found there, and whether they have caused any ecological damage as an invasive species is unknown. In New Zealand, several individuals were liberated in various locations in 1897 and 1899, and a further accidental introduction was made in the 1940s. No sightings have been reported of this species since the 1950s. Depending on their location, green tree frogs occupy various habitats. They prefer moist forests but are not strictly limited to tropical rainforests. They are often found in the canopy of trees near water bodies, but also occupy terrestrial habitats well away from water. They favour old stands of Eucalyptus, where the trees have hollows in which water collects. They are common along inland waterways and