[5] This sparrow is distinctive even within its genus in that it has no plumage differences between the sexes; the juvenile also resembles the adult, although the colours tend to be duller.

[6] Its contrasting face pattern makes this species easily identifiable in all plumages;[4] the smaller size and brown, not grey, crown are additional differences from the male house sparrow.

[2] Adult and juvenile Eurasian tree sparrows undergo a slow complete moult in the autumn, and show an increase in body mass despite a reduction in stored fat.

The change in mass is due to an increase in blood volume to support active feather growth and a generally higher water content in the body.

[7] The Eurasian tree sparrow has no true song, but its vocalisations include an excited series of tschip calls given by unpaired or courting males.

[8] The Old World sparrow genus Passer is a group of small passerine birds that is believed to have originated in Africa, and which contains 15–25 species depending on the authority.

[10] Its members are typically found in open, lightly wooded, habitats, although several species, notably the house sparrow (P. domesticus) have adapted to human habitations.

Most species in the genus are typically 10–20 cm (3.9–7.9 in) long, predominantly brown or greyish birds with short square tails and stubby conical beaks.

This name, and the scientific name montanus, do not appropriately describe this species's habitat preferences: the German name Feldsperling and the Hungarian name mezei veréb ("field sparrow") comes closer to doing so.

[17][18] It is sedentary over most of its extensive range, but northernmost breeding populations migrate south for the winter,[19] and small numbers leave southern Europe for North Africa and the Middle East.

It was introduced successfully to Sardinia,[20][21] eastern Indonesia, the Philippines and Micronesia, but introductions to New Zealand and Bermuda did not take root.

This sparrow has occurred as a natural vagrant to Gibraltar, Tunisia, Algeria, Egypt, Israel, the United Arab Emirates,[5] Morocco and Iceland.

[22] These sparrows are descended from 12 birds imported from Germany and released in late April 1870 as part of a project to enhance the native North American avifauna.

[25] In Australia, the Eurasian tree sparrow is present in Melbourne, towns in central and northern Victoria and some centres in the Riverina region of New South Wales.

[4][5] In Europe, it is frequently found on coasts with cliffs, in empty buildings, in pollarded willows along slow water courses, or in open countryside with small isolated patches of woodland.

[4] The Eurasian tree sparrow shows a strong preference for nest-sites near wetland habitats and avoids breeding on intensively managed mixed farmland.

[31] Roof cavities in houses may be used,[31] and in the tropics, the crown of a palm tree or the ceiling of a verandah can serve as a nest site.

[40] Females that copulate frequently tend to lay more eggs and have a shorter incubation time, so within-pair mating may be an indicator of the pairs' reproductive ability.

It will also feed on invertebrates, especially during the breeding season when the young are fed mainly on animal food; it takes insects, woodlice, millipedes, centipedes, spiders and harvestmen.

Large areas of formerly occupied farmland no longer provide these invertebrate resources due to the effects of intensive farming, and the availability of supplementary seed food within 1 kilometre (0.62 mi) of the nest site does not influence nest-site choice, or affect the number of young raised.

This is in contrast to the house sparrow; in that species, fights to establish dominance are reduced by the display of the throat patch, the size of which acts as a signalling "badge" of fitness.

[49] Although there is evidence that the black throat patch of male, but not female, tree sparrows predicts fighting success in foraging flocks.

Bacteria have been shown to be an important factor in the failure of eggs to hatch and in nestling mortality,[66] and mass deaths due to Salmonella infection have been noted in Japan.

Another study also found that during the winter, Eurasian tree sparrows also exhibited higher levels of thyroid hormone T3, which helps regulate the body’s use of energy.

[26] In the 19th century, there were massive campaigns to catch and kill sparrows in several European countries, including France, Prussia, Hungary, Baden.

[81] The Eurasian tree sparrow has long been depicted in Chinese and Japanese art, often on a plant spray or in a flying flock,[80] and representations by oriental artists including Hiroshige have featured on the postage stamps of Antigua and Barbuda, Central African Republic, China, and the Gambia.

[82] The fluttering of the bird gave rise to a traditional Japanese dance, the Suzume Odori, developed in Sendai, which was depicted by artists such as Hokusai.