European Tree Frog
Identification: Length up to 4.5 cm, usually 3-4 cm. Disc-like adhesive pads on tips of fingers and toes. Pupil horizontal, elliptical. Eardrum visible, no paratoid glands. Skin smooth and shiny on backside, coarse on belly. Back mostly uniform light green, sometimes yellowish or brownish. Belly uniform whitish or light grey. On the border between back and belly, there is a brown stripe, from the nose to the groin area, where it nearly always has a branch that goes upwards and forwards. On the upper side, this band is bordered with a thin yellowish line. Hind limbs are long and thin, with webbing up to half the length of the toes. Throat (vocal sac) in males yellowish or brownish and sometimes longitudinal folds are formed when deflated. In females, the throat is white.
Range: Occurs almost all over Europe, except in the northern parts. There have been many introductions in the British Isles over the past century. These led to successful reproduction in Devon and the Isle of Wight, but the populations were short-lived, as was one that established in south-east London in the 1970's. The most successful colony existed in the New Forest, but it is thought to now be extinct, probably removed by collectors.
Habitat: Prefers dense, sun-exposed vegetation like hedges, bramble patches and reed beds with suitable breeding water not too far away. Breeding in sunny, fish-free waters rather low in nutrients and with a rich sub-aquatic vegetation and dense vegetation around it. In the south of Europe, they occur up to altitudes of 2300 metres.
Habits: Mainly nocturnal and crepuscular, but during the day often seen basking. To protect itself from dehydration, it folds its limbs beneath the body and keeps its eyes closed. Can be found several kilometres away from water. Occurs up to 10 metres high in trees. Breeding from mid-April until the end of June, but in warm springs this may be earlier. The males call mainly at night, from the water surface or from the vegetation at the water edges. At the end of April and the beginning of May, the females lay 300-1400 eggs divided into small clumps of 10-60 eggs attached to water plants. After 1-2 weeks, the eggs hatch. The larvae are 3-5 mm long. After 8 -11 weeks and at a length of about 4.5 cm, they are ready to metamorphose. Sometimes larvae are found in the water in August, but in warm summers they metamorphose as early as mid-June. The newly metamorphosed frogs are 1-2 cm long and look like mature animals. Males sometimes mature after 1 year, females usually after 2 years. When handled, Tree Frogs can produce a bitter secretion. After the breeding season, they live on land, in plants and shrubs. They also overwinter on land under ground between roots of trees or under dead leaves etc.
How to find: Best to localize in the breeding season in the evening and at night by going towards their loud call. Also, you can try searching for basking animals on bramble bushes, twigs etc. during the day in known localities. Sometimes the animals also call in late summer, but not as loud as in spring.
Call: Loud and penetrating "krè - krè - krè ", 4-6 pulses a second. On still nights, it can be heard from over a kilometre away. Calls mainly from sunset and at night, but sometimes also during the day. Most individuals leave the water shortly after midnight.