This sight is quite common on my farm
The white ball of foam is put there by a female foam nesting frog. They even climb my huge marula tree and make foamy nests over my swimming pool.
This photo was taken at what I fondly call frog pond. This is the noisiest place on the farm on warm summer nights when hundreds of frogs get together for a musical evening.
In fact it always reminds me of this song
|(image by Ian. N. White)The grey tree frog – more commonly referred to as the foam nest frog – is the largest of our ‘tree frogs’, with females growing to a length of around 100 mm. The foam nest frog – chiromantis xerampelina – is confined to the northern bushveld, eastern lowveld and south through Swaziland and northern KwaZulu-Natal to the coast.
These frogs are well adapted to a dry, arboreal life although they may frequently visit water to rehydrate. They will rarely be found swimming or sitting in water like many other frogs and toads but are commonly found in and around buildings where lights attract a source of insect food. With a variety of mottled patterns, they can change colour within a range of white to dark grey to match their background and are well camouflaged against tree bark. Females grow much larger and can be double the weight of males.
The common name comes from the whitish clumps of foam that they construct as ‘nests’ in which to lay their eggs. These nests are always constructed on some branch or object over, and often many metres above, water. The females exude a sticky liquid which they kick into a froth with their back legs. Into this foam they lay up to 1000 eggs which are fertilised by, often many, attendant males. The foam prevents desiccation of the eggs and keeping eggs and small tadpoles out of water eliminates much predation.
About five days after hatching the small tadpoles wriggle out of the foam to drop into the water below, where they continue to grow and complete their normal metamorphosis.
(info from http://www.krugerpark.co.za)