Arctic Warbler

The Arctic warbler, scientifically known as Phylloscopus borealis, is a small passerine bird that is a member of the leaf warbler family. It is a typical representative of its family, with a greyish-green back and an off-white underside. A distinctive feature of this bird is its single wing bar, which sets it apart from many similar species.

Identification Tips

When attempting to identify the Arctic warbler, look for its larger size compared to the greenish warbler, Phylloscopus trochiloides, and its heavier, dagger-like bill. The lower mandible of the bill has a notable dark tip. The single wing bar is a key characteristic to distinguish it from other warblers.

Habitat

The Arctic warbler can be found in birch or mixed birch forests, often in proximity to water sources within its breeding range.

Distribution

This warbler breeds across Fennoscandia and the northern Palearctic and has also established a breeding presence in Alaska. It is a highly migratory species, spending winters in southeast Asia, which accounts for one of the longest migrations among Old World insectivorous birds.

Behaviour

The Arctic warbler is known for its strong migratory patterns, with the entire population relocating to southeast Asia during the winter months. It is also an autumn vagrant in western Europe and is observed annually in Great Britain.

Song & Calls

The song of the Arctic warbler is a rapid trill, a delightful auditory marker for birdwatchers to identify this species in the wild.

Breeding

Nesting for the Arctic warbler occurs on the ground within low shrubs, a common trait among Old World warblers.

Similar Species

The Arctic warbler is similar in appearance to the greenish warbler, Phylloscopus trochiloides, but can be differentiated by its larger size, heavier bill, and the dark tip on the lower mandible.

Diet and Feeding

As an insectivorous bird, the Arctic warbler feeds primarily on insects, foraging through the foliage in its habitat.

Conservation status

The IUCN Red List has classified the Arctic warbler as Least Concern, indicating that currently, there are no immediate threats to its population numbers that would warrant a higher level of concern.

In the quiet of the birch forests, one might be fortunate enough to encounter the Arctic warbler, a small bird with a grand migratory journey, whose presence is a testament to the wonders of avian endurance and adaptability.