Phylloscopus trochilus
Silhouette: Margot Michaud · PhyloPic
In 3 days ~40% in a week ~70%
The willow warbler (Phylloscopus trochilus) is a very common and widespread leaf warbler which breeds throughout northern and temperate Europe and the Palearctic, from Ireland east to the Anadyr River basin in eastern Siberia. It is strongly migratory, with almost all of the population wintering in sub-Saharan Africa.
It is a bird of open woodlands with trees and ground cover for nesting, including most importantly birch, alder, and willow habitats. The nest is usually built in close contact with the ground, often in low vegetation. Like most Old World warblers (Sylviidae), this small passerine is insectivorous. In northern Europe, it is one of the first warblers to return in the spring, though later than the closely related chiffchaff. In spite of its small size, the willow warbler performs one of the longest migrations of any animal.
The willow warbler was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Motacilla trochilus. The willow warbler is now one of around 80 species placed in the genus Phylloscopus that was introduced by the German zoologist Friedrich Boie in 1826. The genus... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Nizhny Novgorod | 🇷🇺 Russia | |
| 2 | Helsinki | 🇫🇮 Finland | |
| 3 | Jerusalem | 🇮🇱 Israel | |
| 4 | Manama | 🇧🇭 Bahrain | |
| 5 | Saint Petersburg | 🇷🇺 Russia | |
| 6 | Tehran | 🇮🇷 Iran | |
| 7 | Moscow | 🇷🇺 Russia | |
| 8 | Manchester | 🇬🇧 United Kingdom | |
| 9 | Kazan | 🇷🇺 Russia | |
| 10 | Yekaterinburg | 🇷🇺 Russia |
With luck
About 10% of wildlife watchers report a Willow Warbler sighting in Arusha National Park on a given day, based on 105 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 118th most-seen of the 373 birds we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
February and March
In those months about 30% of wildlife watchers report a Willow Warbler in Arusha National Park on a given day, against under 5% in May to September, the lowest months.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Willow Warbler sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
10th of 74
Of the 74 parks where we can rate Willow Warbler sightings, Arusha National Park ranks 10th at about 10%. The best odds are in Biebrza National Park (Poland, about 50%), Cairngorms National Park (United Kingdom, about 50%) and Tatra National Park (Slovakia, about 30%). All parks ranked.
GBIF citizen-science records
It is estimated from how often the Willow Warbler is recorded against all the birds logged in Arusha National Park (105 verified sightings from 2019 to 2026), 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.
