© Copyright: Images: Jari Peltomäki, Jouko Lehmuskallio, M. & W. von Wright (Kansalliskirjasto, The National Library of Finland) . Recording: Jan-Erik Bruun. All rights reserved.
- Name also: Eurasian Tree Sparrow, German Sparrow
- Family: Sparrows – Passeridae
- Appearance: Smaller and more slender than the similar House Sparrow. Males and females both have chocolate brown caps and white cheeks with a dark patch.
- Size: Length 12.5–14 cm, weight 22–24 g.
- Nest: In nest-boxes or holes in buildings, made of grass, lined with feathers, hair, threads etc.
- Breeding: 4–8 eggs laid April–May, incubated by both parents for 11–14 days. Fledglings remain in nest for 13–17 days. Often raises two broods each summer.
- Distribution: Hs spread during recent decades into settlements and rural areas around Finland. Today breeds as far north as Southern Lapland, and has become more common than the House Sparrow in many areas. Finnish breeding population estimated at 140,000–200,000 pairs.
- Migration: Sedentary, though some of the most northerly populations move further south for the winter. Most likely to migrate October–November and March–May.
- Diet: Seeds, invertebrates.
- Calls: Like call of House Sparrow but harsher and more aggressive.
Tree Sparrows have dark brown caps, white cheeks with a dark patch, a black bib, and a whitish ring round the back of their necks. Their backs are streaked brown and black, and their bellies are pale grey. Two white stripes can be discerned on their wings. Unlike the House Sparrow, both sexes have the same plumage. Tree Sparrow’s legs are pale brown, and their beaks are black in summer and brownish black with a yellowish base in winter. Their irises are dark brown.
Tree Sparrows may interbreed with House Sparrows, producing hybrid offspring that look more like Tree Sparrows.