Hyla arborea
Silhouette: Luca Leicht · PhyloPic
In 3 days ~10% in a week ~30%
The European tree frog (Hyla arborea) is a small tree frog. As traditionally defined, it was found throughout much of Europe, Asia and northern Africa, but based on molecular genetic and other data several populations formerly included in it are now recognized as separate species (for example, H. intermedia of Italy and nearby, H. molleri of the Iberian Peninsula, H. meridionalis of parts of southwestern Europe and northern Africa, and H. orientalis of parts of Eastern Europe, Turkey and the Black Sea and Caspian Sea regions), limiting the true European tree frog to Europe from France to Poland and Greece.
European tree frogs are small; males range from 32–43 mm (1.3–1.7 in) in length, and females range from 40–50 mm (1.6–2.0 in) in length. They are slender, with long legs. Their dorsal skin is smooth, while their ventral skin is granular. Their dorsal skin can be green, gray, or tan depending on the temperature, humidity, or their mood. Their ventral skin is a whitish color, and the dorsal and ventral skin is separated by a dark brown lateral stripe from the eyes to the groin. Females have white throats, while males have golden brown throats with large (folded) vocal... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Hortobágy National Park | 🇭🇺 Hungary | |
| 2 | Kiskunság National Park | 🇭🇺 Hungary | |
| 3 | Fertő-Hanság National Park | 🇭🇺 Hungary | |
| 4 | Bavarian Forest National Park | 🇩🇪 Germany |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Skansen | 🇸🇪 Sweden | |
| 2 | Slimbridge Wetland Centre | 🇬🇧 United Kingdom | |
| 3 | Wildpark Schwarze Berge | 🇩🇪 Germany | |
| 4 | Berlin Zoological Garden | 🇩🇪 Germany | |
| 5 | Universeum | 🇸🇪 Sweden | |
| 6 | Freiland-Aquarium und -Terrarium Stein | 🇩🇪 Germany | |
| 7 | Aquarium Berlin | 🇩🇪 Germany | |
| 8 | Fluviário de Mora | 🇵🇹 Portugal | |
| 9 | Baltic Sea Science Center | 🇸🇪 Sweden | |
| 10 | Lake Tisza Ecocentre | 🇭🇺 Hungary | |
| 11 | Löbbecke Museum und Aquazoo | 🇩🇪 Germany |
Rare
Under 5% of wildlife watchers report a European Tree Frog sighting in Vienna on a given day, based on 13 verified sightings from GBIF citizen-science data. It is the 9th most-seen of the 11 amphibians we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
April–June and August
In those months about 10% of wildlife watchers report a European Tree Frog in Vienna on a given day, against under 5% in July and September–March, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most European Tree Frog sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 cities where we can rate European Tree Frog sightings, Vienna ranks 2nd at under 5%. The best odds are in Munich (Germany, about 10%).
Same order: Anura
The closest relatives of the European Tree Frog that you can see in Vienna (order Anura, Frogs and Toads) are European Toad (about 30%), Agile Frog (about 20%) and Green Toad (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the European Tree Frog is recorded against all the amphibians logged in Vienna (13 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
