European tree frogHyla arborea — habitat, diet and reproduction

Bright green tree frog with a dark side stripe clinging to a twig

European tree frog (Hyla arborea) on a twig. · Charles J. Sharp / CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0). Cropped and resized.

The European tree frog is a small, bright green frog that lives in bushes and trees rather than in water. Its toes end in sticky pads that help it climb even smooth leaves. In spring, males call in loud evening choruses, surprisingly loud for their size.

Quick facts

Common name	European tree frog
Scientific name	Hyla arborea
Lifespan	A few years in the wild; up to about 15 in captivity
Length	About 3–5 cm
Diet	Carnivore: flying insects and spiders
Predators	Birds and snakes; fish and water insects take tadpoles
Conservation status	Least Concern (LC); strictly protected in the EU
Distribution	Europe and western Asia
Habitat	Shrubs, reedbeds and trees near sunny ponds
Family	Hylidae
Reproduction	Eggs laid in water in small clumps

Interesting facts

A tree frog chorus can be heard over a kilometre away on quiet nights.
It can change shade from bright green to grey or brown.
The male has a vocal sac under the chin that inflates like a balloon when calling.
Its sticky toe pads hold it even to windows.

Characteristics

The tree frog has smooth, bright green skin and a dark stripe running from the nose through the eye and along the flank. The belly is white or yellowish.

Toe tips are widened into sticky discs. Males have a yellowish or brownish throat containing the vocal sac. Colour can change with temperature, humidity and the animal’s state.

Behaviour

Outside the breeding season, the tree frog lives in shrubs, reeds and tree canopies. By day it sits still on leaves, even in sunshine, and hunts in the evening.

In spring, males gather at ponds and give a fast, loud “crek-crek-crek”, and females choose males by their calls. In winter it hibernates on land, under leaves, in crevices or in the soil.

Habitat and distribution

The species lives across much of Europe, from Iberia to the Caucasus and western Asia. It is absent from Britain, Ireland and northern Scandinavia.

In Romania it is widespread in lowlands and hills, especially near sunny, vegetated ponds, and is common in the Danube Delta and river floodplains.

Diet and feeding

The tree frog eats flying insects such as flies, mosquitoes and moths, as well as spiders and small beetles.

It waits on leaves and leaps at prey, catching it with its mouth and sticky tongue. Tadpoles eat algae and plant debris.

Reproduction and life cycle

Breeding takes place in spring in shallow, sunny ponds without fish. The female lays a few hundred eggs in small clumps attached to plants.

Tadpoles have a tall tail fin and eyes set on the sides of the head. After about two to three months, tiny green froglets leave the water and climb into vegetation.

Name and history

The scientific name Hyla arborea means “tree frog”. Hylas was a figure in Greek mythology, and “arborea” comes from the Latin for tree.

People once kept tree frogs in jars with a little ladder, believing that if the frog climbed, good weather would follow. This is a superstition, not a forecasting method.

Conservation and threats

The species is assessed as Least Concern, but populations are declining in many countries. In the EU it is strictly protected under Annex IV of the Habitats Directive.

Main threats include ponds drying out, pesticides, fish stocked in ponds and clearing of bankside shrubs. Small, sunny, fish-free ponds are essential for it.