Spanish Sparrow (Passer hispaniolensis) size is about 15 cm in length. It is closely related to House Sparrow. The adult male summer is noticeably different from the House Sparrow, having a black bib extending over the breast and long, broad black streaks extending well down flanks, crown rich chestnut (bordered by thin white supercilium), sides of the head is much whiter and upperparts heavily streaked with black and off-white.
The adult male bird winter in fresh plumage in autumn has pale buffish fringes to head and body feathers that dull color of crown and cheeks, and largely obscure black on both underparts and upperparts. They show dull, rather pale underparts and mantle, with extensive dusky streaking on the sides of the breast, flanks, and mantle; the buff fringes to the crown feathers can create a pale-centered appearance to the crown (signifying House, but grey coloration lacking).
The adult female and juvenile are very comparable to adult female/juvenile House Sparrow, but bill slightly larger and stouter, being a little longer and deeper-based. The gape is usually longer, ending just below the leading edge of the eye (typically slightly in front of the eye in House), and the forehead often appears steeper, but neither of these features is consistently reliable.
Supercilium tends to be longer, broader, and paler (creamier, less brownish) behind the eye than in House and more often extends narrowly in front of the eye also (in House, supercilium generally absent or less conspicuous in front of the eye). The Ear-coverts are typically, but not always, darker than in House Sparrow, contrasting less with dusky eye-stripe. Pale ‘braces’ running across upper scapulars usually appear more prominent and paler in Spanish, and pale tips to median coverts are often whiter.
The tertial fringes and pale wing panel on the closed wing formed by the secondary fringes tend to become visible paler and sandier (more rufescent in House). The belly of Spanish Sparrow is whiter, and most have weak diffuse dark streaking or mottling on breast and flanks, but this differs in intensity and even adult female House Sparrow may show a clue of streaking below (particularly when heavily worn in summer).
None of the above differences is diagnostic, however, and so careful assessment of a combination of features needs to be made: even so, some individuals will be indistinguishable. Extensive hybridization in some areas further complicates the picture. Sociable, breeding colonially in avenues of trees and in riverside bushes, often in very large numbers; also small colonies found in bases of nests of large birds such as White Storks.
On passage and in winter, forms very tightly packed flocks. A bird of the countryside is hardly ever directly about habitation except where the House Sparrow is absent, i.e. Malta, parts of Tunisia, Canary, and Cape Verde, much the same as for the House Sparrow.
Spanish Sparrow calls are similar to those of House Sparrow, but ‘chirp’ and ‘chirrup’ are a little fuller and more abrupt (perhaps more metallic), and flight call distinctly harsher, ‘churrp’ rather than ‘churrrip’. The excitement rattle is slightly shorter and deeper than that of House. Males give a loud ‘chee-chee-chee-cheee’ at colonies. Spanish Sparrow’s song is similar to that of House but slightly higher and more metallic.
There are two races rather paler races (at least in winter plumage) transcaspicus occupies the Asian part of the range. Some of the Mediterranean island populations, e.g. Malta, are somewhat intermediate between Italian and Spanish Sparrows, but are usually included within Spanish: this form is now often referred to as ‘hybrid form x malta.
It is locally hybridized with House Sparrow, the hybrids often resembling ‘Italian Sparrow’ (q.v.); hybridization with Eurasian Tree Sparrow is also very rarely recorded. Spanish Sparrow is locally common in most areas but rather uncommon and localized in the Iberian Peninsula. Therefore, the Eastern population is highly migratory, migrating south as far as Egypt and Arabia. The farmland with bushes and trees, groves, and thickets is in an open or hilly country. Often found nearby water (including reed beds), but only locally about habitation.