Icterine Warbler

The icterine warbler (Hippolais icterina) is a small passerine bird that breeds primarily in central and northern Europe, with a range extending from Scandinavia to the Mediterranean and eastwards to Russia. It winters in Africa, mostly south of the Equator. It is a fairly large warbler, and adults typically measure about 12-14 cm (4.7-5.5 in) in length and weigh around 11-15 grams (0.38-0.53 oz). This species is identified by its greenish-grey upperparts and yellow underparts. It has a distinctive, loud, and varied song, which often includes mimicry of other birds. The icterine warbler is very similar to the closely related melodious warbler (Hippolais polyglotta), found in Southwestern Europe, but the melodious warbler typically has browner upperparts. The icterine warbler also has a slightly longer primary projection than the melodious warbler, and a significantly paler wing panel. 

The icterine warbler inhabits a variety of habitats, including deciduous and mixed woodlands, gardens, and parks. It favors areas with abundant shrubbery and undergrowth, which provide ample foraging opportunities. The diet of the icterine warbler primarily consists of insects and other invertebrates, such as caterpillars, beetles, and spiders. It also consumes berries and fruits, especially in the latter part of the summer. The bird forages actively, often seen gleaning insects from foliage or catching prey mid-air in a style reminiscent of flycatchers.

This species is a long-distance migrant, wintering in sub-Saharan Africa, primarily south of the Equator. The migration period typically begins in late August or early September, with birds traveling southward over the Mediterranean and through the Sahara to reach their wintering grounds. They return to their breeding areas in Europe around May. The journey is a remarkable feat, covering thousands of kilometers, and involves crossing challenging landscapes such as deserts and seas.

The breeding season for the icterine warbler generally occurs from May to July. During this time, males establish territories and attract mates through their vocal displays. The species constructs a cup-shaped nest, usually placed in a shrub or low tree, often concealed among dense foliage. The female lays 4-6 eggs, which she incubates for about 11-13 days. Both parents are involved in feeding the chicks, which fledge approximately 10-12 days after hatching. The young are dependent on their parents for a short period post-fledging as they learn to forage independently.

The icterine warbler is currently listed as least concern by the IUCN, owing to its wide range and stable population numbers. However, like many migratory birds, it faces threats from habitat loss both in its breeding and wintering grounds, as well as from environmental changes and climate change impacting its migratory routes.