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Home , Fringilla, House Sparrow, Italian sparrow

Studies of West Palearctic 193. * J. Denis Summers-Smith

he House Sparrow domesticus must be one of the most familiar birds, Tnot only in the Palearctic and Oriental Regions that are its natural range, but also in much of the rest of the world into which the has been introduced and where it has tiirived most successfully. Its familiarity depends on the fact that throughout very much of its range it is closely associated wim man, nesting on his houses and feeding on grain, feedstuffs and scraps provided by man in towns and gardens. Not only is the House Sparrow familiar to anyone interested in birds (and even to those who are not), but it is also one of the most studied. This is partly because it is considered a pest species in many parts of its range, and also because, being unprotected, it has been used as a laboratory animal or even 'sacrificed' without causing undue concern. It has been the subject of a monograph (Summers-Smith 1963) and was treated at length in a more recent study of the (Summers-Smith 1988); it is the dominant species within the occasional journal International Studies on Sparrows and in four books emanating from the Polish Academy of Sciences (Kendeigh & Pinowski 1973; Pinowski & Kendeigh 1977; Pinowski & Summers-Smidi 1990; Pinowski et al. 1991). A symposium was devoted to North American studies on the species (in Fayetteville, Arkansas, in 1969: Hardy & Morton 1973); it was the subject of another symposium, at the XVII International Ornithological Congress in 1978; and, more recendy, received full treatment in Birds of North America (Lowther & Cink 1992). In this review, therefore, I propose to concentrate on those aspects of special current interest that I consider worth highlighting.

Taxonomy The House Sparrow does not present identification problems, certainly not the male widi his dark grey crown, chestnut nape, white cheeks, and black *This paper, and others in this long-running British Birds series, will be published in a forthcoming HarperCollins book.

{Bril. Birds 87: 593-602, December 1994] 593 594 Studies of House Sparrows chin and bib, though the dull brown female is less distinguished. The same, however, cannot be said about its . Linnaeus in his of 1758 described it as a domestica (the Latin fringilla probably referred to the Chaffinch Fringilla coelebs). Brisson changed the genus to Passer in 1760, though still retaining it in the finch Fringillidac. In 1927, Passer was moved by Sushkin to the weaverbirds (family Ploceidae), both on anatomical grounds and because of its nest architecture, though not with universal acceptance. Although the nests built by the sparrows are domed, they tend to be loose untidy heaps, bearing little resemblance to the beautifully constructed nests of the ploceine weavers. The final contribution to this saga comes from the protein and DNA analysis studies of Sibley and his co-workers, who seem to veer between placing the sparrows in a new family Passeridac, together with die related rock sparrows Petronia and snowfinches Montifringilk, or as a subfamily, P&sserinac, in the Passeridac, which includes among others the weavers in the subfamily Ploceinae (Sibley & Ahlquist 1990; Sibley & Monroe 1990). It seems clear that there is no general agreement on the relationship between the sparrows and the other great sccd-eating groups: the , the weavers and the buntings. One other taxonomic problem remains: the relationship between the House Sparrow and the Spanish (or Willow) Sparrow Passer hispanioknsis. Over much of their ranges, these two birds live separately as good species, but in northwest Africa they interbreed freely, forming a complete range of intermediates; whereas in Italy, south from the to about the latitude of Rome, there is a stabilised , the so-called , intermediate in between the two, and from there southwards to Pantelleria there is a steady clinc from the pure Italian Sparrow to pure hispanioknsis. Are we dealing with one species or two separate ones? Our taxonomic rules do not easily cope with this problem, though I tend to support the view 'that as the hybrid population has resulted from events long past, and is currendy stable with little inflow from the parent species, the taxon might well be given specific rank' (Johnston 1969). Confirmed tickers will surely agree.

Origins The most striking character of the House Sparrow, as already mentioned, is its close association with man. All the sparrows arc sccd-eaters, taking especially the seeds of grasses, and it seems likely tiiat diis association between the House Sparrow and man originated in me Fertile Crescent of the where man evolved, about 10,000 years ago, from a hunter-gatherer to a settled agriculturist, cultivating the wild and barley that were the precursors of our present grains and were no doubt already part of the diet of the sparrow inhabiting those parts. Not only did this association provide a source of food, both in the fields and in the feedstuffs put out for man's domestic stock, but, in addition, man's dwellings provided good, safe nest sites. Provision of an assured food supply throughout die year enabled the House Sparrow to adopt a completely sedentary way of life, many individuals, as shown by ringing results, nowadays living out their lives no more man a kilometre or two from their birthplace. As we shall sec later, this has important effects on its life style and behaviour. It is worth pointing out, 171. Adult male House Sparrow Passer domesticus drinking, Kent, June 1989 (R. J. Chandler). Note jet-black breeding-season bill colour 172. Male House Sparrow Passer domesticus, Scilly, autumn 1983 (Robin Chittenden). Note grey/horn/yellowish out-of-breeding-season bill colour. Extensive black bib is masked by pale tips, which will have been abraded by spring to create the full black chin, throat and upper breast of the male in the breeding season 596 Studies of House Sparrows however, that such extreme sedentary behaviour is by no means always the case. Two races are migratory: P. d. bactrianus, which breeds in and Russian Turkestan, winters in northern Pakistan and India, with ringing recoveries showing movements of 1,500-2,000 km; P. d. parkini, which breeds above 2,000 m in the Karakorams and , is largely migratory, descending to lower altitudes in die winter. In the breeding range of bactrianus, the sedentary Tree Sparrow P. montanus has pre-empted the 'house sparrow' role (as it does in those parts of the East where the House Sparrow does not occur) and lives in the towns and villages, whereas the migratory House Sparrow is forced out into open country, where it breeds away from man in holes in cliffs and embankments. Close association with man, however, remains the rule, and has been exploited by the species to an extraordinary degree. House Sparrows are able to survive the long winter nights north of the Arctic Circle by moving into the byres widi the cattle, where the cold is mitigated and food is readily available. Other House Sparrows, such as those that used to occupy the air-conditioned Queen's Building at London's Heathrow Airport when it was the main passenger terminal and the ones that bred in Frickley Colliery (Summers-Smith 1980), provisioned by the miners 640 m below ground level, have completely forsaken a natural outdoor environment.

Range The natural range of the House Sparrow extends from die western seaboard of Europe east to the Pacific coast of Siberia, with a dramatic extension of some 5,500 km from the Urals to the mouth of the river Amur in a litde over 100 years following the development of agriculture and the building of the Trans-Siberian railway. In the south, it extends to North Africa north of the Sahara, through the Middle East to die Indian peninsula and and just into nordiern Burma. It is lacking in Thailand, Indo-China, China, just penetrating Heilungkiang Province in the extreme north, and Japan, though there is one record of a male and two young in northwest Hokkaido in August 1990 (Sano 1990). The range has been gready extended by deliberate introductions by man to most of the major inhabited parts of the world, including North and South America, , and , in all of which it has spread very successfully. It would take too long to describe all of the colonisations, though some are particularly worthy of note. Perhaps the most interesting is the situation that is developing at the junction between North and South America. House Sparrows from the North were first reported from in 1976 (Reynolds & Stiles 1982), whereas in the South they were in Amazonia in 1965 (Muller 1967) and in Colombia in 1986 (C. Hinkelmann verbally). Venezuela remains unconquered, though House Sparrows arc already close by, on Curacao, having escaped from an aviary there in 1953 (Voous 1983), and invasions from north and south can surely not be long delayed and the two populations, bodi originally from , will meet up again after a separation of nearly 150 years. During this time, the two populations have been evolving along different evolutionary lines and interbreeding should provide fruitful material for DNA studies. Studies of House Sparrows 597 Although these major introductions were at the hand of man, there are many instances of unaided spread, probably mostly by involuntary ship-borne invaders. The best-recorded instance is the colonisation of the Falkland Islands in 1919 by about 20 House Sparrows that travelled aboard four whaling vessels from Montevideo in Uruguay (Bennett 1926), and this method probably also accounted for the colonisation of the Cape Verdcs that occurred between 1922 and 1924 (Bourne 1966), the Faroes in 1934 or 1935, and Senegal about 1970. Sparrows with grey heads have recendy been reported among the introduced population of Spanish Sparrows on Madeira, though nothing is known of their provenance or mode of arrival. With a recent report of the introduced sparrows on the Azores travelling between the islands on the inter-island planes (G. Le Grand verbally), nothing seems beyond the capacity of this intrepid .

Breeding The extreme sedentary way of life has allowed the House Sparrow to form pairs that are maintained for life. One pair of my colour-ringed population remained together for four years, raising at least seven broods in the same nest. Recent studies, however, suggest that perhaps all is not as it appears on the surface. DNA investigations have shown that 10% to 20% of the chicks in nests have not been sired by the male attending the nest (Parkin & Wetton 1991; Wetton & Parkin 1991a). The female successfully conceals this from human observers—Wetton & Parkin (1991b) observed only one extra-pair in 58 cases, whereas they found 73 extra-pair fertilisations out of 536—and no doubt from her mate as well, to ensure his faithful co-operation in raising the young, though cloaca-pecking and the repeated and frequent copulations observed at the nest suggest diat the male may be aware of the risk of being duped. But there are even more bizarre happenings. In a study in Spain, it was suggested that widowed birds would destroy the or young in a neighbouring nest to induce the bird of the appropriate sex to and pair with the murderer (Veiga 1990), preferring the replacement to be an experienced bird rather than a non-breeding floater! Arc we becoming too obsessed with sex? The observations of those who have studied House Sparrows intensively in the field do not seem to be consistent with the views of their sex-oriented colleagues. Remaining in the same area throughout the year allows die House Sparrow to take advantage of the opportunity to start breeding early and to extend the breeding season as long as conditions remain favourable, without having to take into consideration the need to migrate. Three broods are not uncommon in temperate regions, and up to seven attempts, including four successful ones, have occurred in one year in the Indian tropics, breeding being interrupted only by the energetic demands of the moult (Naik & Mistry 1980). The adaptability of the species is shown by its catholic choice of nest sites. Holes in buildings and other man-made structures (street lights arc a regular site, the birds no doubt benefiting from the central heating) are the commonest sites, but natural cliff holes arc also used, and nests arc frequently built openly in the branches of trees or on telegraph poles, the habit being more frequent in the warmer Mediterranean region tiian at higher latitudes. 173. Two female Huusc Npanims Passer domesticus fighting,Nort h Yorkshire, March 1992 (E. A. Janes). While such fighting between two individuals of the same sex can often be seen during the breeding season, iights between the two sexes almost nevcr oceur 174. Female House Sparrow Passer domesticus bathing, Kent, June 1989 (R. J. Chandler). Bathing and dust-bathing are frequent activities throughout the year Studies of House Sparrows 599 Again, it is the bizarre that attracts interest. Moving sites are not uncommon; these usually involve only limited movement, such as occurred on the 'nodding donkeys' in an oilfield in Kansas, USA, and on a coke-oven ram- machine in a steel-works in south Wales, but pairs have also nested on more mobile sites. There is a case of a pair that nested on a house boat on the , staying with it as it made journeys of up to 30 km (Meinertzhagen 1949); while another pair nested under the bonnet of a gamekeeper's van that made regular trips around an estate during the day {Middlesbrough Evening Gazette, 18th May 1966).

Numbers It is generally accepted that a noticeable decrease in House Sparrow numbers occurred in urban areas in the UK and North America in the 1920s. This was attributed to the replacement of the horse by the automobile that not only reduced the availability of food from spillage from nosebags, but also made the streets a more dangerous place because of the increasing speed of the vehicles. After a period of relative stability, if not of increase in numbers, with the growth of the suburban areas much to the liking of the sparrows, we now seem to be in the middle of another period of decline. Census results have indicated a strong decrease in House Sparrows in Denmark during 1977-79, with similar falls in both the UK and starting in the early 1980s (Marchant et al. 1990). Confirmation of the UK decrease is given by censuses carried out by Lewis (1984) in an area of the Berkshire Downs in 1967 and repeated in 1981; die census for the latter year showed a marked drop in breeding numbers and the almost complete disappearance of autumn passage that had been a feature of the earlier survey. Further evidence is given by the Common Birds Census organised by the British Trust for Ornithology, showing a decline of 15-20% over the period 1978-88 (Balmer & Marchant 1993), though it should be noted that this refers particularly to farmland, which, as Heij (1985) has shown, is not the primary habitat for the House Sparrow and is thus likely to exaggerate the situation (see below). This decline appears to be widespread over much of western Europe; for example, transect counts around Lake Constance show a 22% decrease in the decade 1980/81 to 1990/91 (Bauer & Heine 1992). The remaining evidence is rather more anecdotal in character, but nonetheless very convincing, as it comes independendy from several different countries. In the , a decrease in breeding numbers was reported from Renkum, Gelderland, in 1980 (Woldendorp 1981), and in 1982 it was noted that House Sparrows were in sharp decline in the Faroe Islands (Bloch 1982). In the UK, several participants in the Garden Bird Feeding Survey organised by the BTO remarked on a decline or even complete absence of House Sparrows in their gardens in 1989 (Muirhead 1989), while a correspondent to one of the national newspapers noted a dearth of House Sparrows in parts of Suffolk in 1991 (Burton 1991). Brucker (1993) remarked that the population of the House Sparrow in the Oxfordshire countryside, high in the 1940s, had recently plummeted to a comparatively low level. Further, seven out of nine correspondents to British Birds in 1993 reported a significant decrease (Sharrock 1993; Balmer & Marchant 1993). 600 Studies of House Sparrows I have found from personal observations in northeast England that a number of the more isolated breeding colonies have disappeared in recent years. In the vicinity of farmhouses, where there used to be flocks of 20-30, there are now fewer than ten. House Sparrows ceased breeding around my house in County Cleveland in the 1970s, and the erection of a sparrow pot on the wall of the house in 1981 has failed to persuade them to return. In fact, House Sparrows arc now only rare visitors to my garden, in some years being outnumbered even by Hawfinches Coccothraustes coccothraustesl We may also ask what has happened to the large flocks at the ripening grain fields that used to be such a feature at the edges of built-up areas in the late summer. Finally, from Germany there is a most interesting account in a rather unlikely source, an article cntided 'Unser Spatz piepst das Lied von Tod' (Our spuggy peeps the song of death) in the popular magazine Bunte (Droscher 1992). The author remarks that the House Sparrow has become, a rarity in West Berlin, though it is still common in East Berlin. He suggests that the underlying reason for this difference is the absence of in the more affluent west, through the widespread use of garden pesticides, whereas in the cast little of this occurs as yet. The species thus appears to be in decline over much of western Europe from Scandinavia to Belgium and Britain. Taking everything into con­ sideration, I suggest that the population in die British Isles peaked at about 11.5 million from 1981 to 1984 and has now probably fallen to less than 9 million. I can only speculate on some possible reasons for the decline. A Dutch study, in which comparative observations were made in urban, suburban and agricultural areas in and around Rotterdam (Heij 1985), provides a useful starting point. In general, the House Sparrows were most successful in the 'green' suburban area, where the population was self-sustaining. In contrast, both the urban and rural areas were less successful and depended on immigration for the maintenance of numbers. While the House Sparrow is essentially a granivore, the young are reared principally on invertebrates, a diet of animal food for the first three days at least being essential for survival. Older chicks are still given animal food, but this can be increasingly supplemented by vegetable food as they approach fledging. A restricted availability of insects may always have had a limiting effect on the breeding success of urban populations, but may now be having an effect on suburban and rural populations as well, owing to increased use of pesticides both on agricultural land and in suburban gardens. Changing farming practices may be having an additional effect in agricultural areas. The latter includes reduction in the diversity of the vegetation: production of - free crops, removal of hedgerows and the ploughing-up of headlands. In addition to die effect of reduced invertebrate availability on productivity, the disappearance of die barnyard fowl from many farmyards and the change from spring-sown to autumn-sown cereal cultivation must have reduced the availability of food throughout the year and have exerted pressure on the survival of the full-grown birds. Tawny Owls Strix akico and domestic are effective predators of House Sparrows. For example, Churcher & Lawton (1987), who made a study of the Studies of House Sparrows 601 prey taken by cats in an English village, came to the conclusion that 'domestic cats were a significant, perhaps even the most important, source of mortality for house sparrows in the village'. This must apply equally to suburban areas, where cats arc numerous. No doubt sparrow populations were in equilibrium with this pressure, and there is no evidence to suggest any change in this situation that could account for the decline in sparrow numbers. Predation pressure on suburban House Sparrows has, however, probably mounted through the increase in numbers of Eurasian Sparrowhawks nisus, now a familiar member of die suburban avifauna that dramatically increased in numbers following the withdrawal of the organochlorine pesticides (Marchant et al. 1990). While not important by itself, this could be an additional factor leading to a new equilibrium at a lower population level.

Relations with Tree Sparrows In the Far East, where die House Sparrow is absent, the Tree Sparrow takes over the 'house sparrow' role, living in close association with man in exactly the way that the House Sparrow does in Europe. The two species are thus potential competitors in areas where they overlap. The larger House Sparrow is normally dominant, although, as already mentioned, the Tree Sparrow retains the domestic role in Afghanistan and Russian Turkestan, where the House Sparrow is a summer visitor. At the limit of the House Sparrow's range in Assam, however, both species live together around man's buildings, and to the south in Burma the Tree Sparrow becomes the dominant house bird, with the House Sparrow displaced to more rural areas. With two species adapted to the same , there must be a risk of interbreeding, and it seems most likely that the adoption of the 'male' plumage by the female Tree Sparrow has evolved as a species-isolating mechanism. If this is the case, it is not entirely successful. In a study of hybridisation between the species, Cordero & Summers-Smith (1993) were able to cite 33 instances (since then increased to 47). We came to the conclusion that mate restriction was the most likely cause of hybridisation, where one or even both of the species were locally rare and individuals had difficulty in finding a mate of their own species; in the absence of a proper mate, a male House Sparrow would mate with a female Tree Sparrow, even though it would look 'wrong', and vice versa. In most of the cases investigated, the rarer species was the Tree Sparrow, diough in one case both were uncommon. The hybrids appear to be not only viable, but also fertile and capable of breeding, indicating that the two species are genetically very closely related.

References BAIJUER, D., & MARCHANT, J. 1993. The sparrows fall. Brit. Birds 86: 631-633. BAUKR, H.-G., & HKINK, G. 1992. Die Entwicklung der Brutvogelbestande am Bodensee: VergleichhalbquantitativerRasterkartierungen 1980/81 und 1990/91. J. Orn. 133: 1-22. BENNEIT, A. G. 1926. A list of the birds of the Falkland Islands and Dependencies. Ibis 68: 306- 333. Bl.OCH, D. 1982. In: European news. Brit. Birds 75: 25-30. BOURNE, W. R. P. 1966. Further notes on the birds of the Islands. Ibis 108: 425-429. 602 Studies of House Sparrows

BRUCKER, J. 1993. Sparrows for sale again? Oxford Orn. Soc. Newsletter, March 1993. BURTON, R. 1991. Nature note. Daily Telegraph, 14th December 1991. CHURCHER, P. B., & LAWTON, J. H. 1987. Predation by domestic cats in an English village. J. Mediterranean basin. Condor 7 ]: 129-139. KKNDKICH, S. C, & PINOWSKI, J. (eds.) 1973. Productivity, Population Dynamics and Syskmatks of Granksorous Birds. Warsaw. LEWIS, L. R. 1984. Observations on the status of the House Sparrow in the Newbury district. Newbury District Orn. CI. Ann. Rep. 34-39. LOWTHKR, P. E., & ClNK C. L. 1992. House Sparrow. In: POOLE, A., Sl'ElTEMHEIM, P., & Gll.1, F. (eds.) The Birds of North America No. 12. Washington. MARCTHANT, J. H., HUDSON, R., CARTER, S. P., & WHITTINGTON, P. (eds.) 1990. Population Trend* in British Breeding Birds. Tring. MKINKRTZHAOEN, R. 1949. Notes on Saudi Arabian birds. Ibis 91: 465-482. MlHRHEAl), L. (compiler) 1989. Where are the House Sparrows? BTO/BASF Garden. Bird Survey Newsletter 4: 3-4. Mdu.ER, P. 1967. Zur Verbreifung von Passer domestkus in Brasilien. J. Orn, 108: 497-499. NAIK, R. M., & MlS'l'RY, L. 1980. Breeding season in a tropical population of the House Sparrow. J. Bombay Nat. Hist. Soc. (Suppl.): 1118-1142. PARKIN, D. T., & WKTEON, J. H. 1991. The heritability of tarsus length in House Sparrows Passer domesticus. Bis 133 Suppl. 1: 134. PINOWSKI, J., CAVANAGH, B. P., & GORSKI, W. (eds.) 1991. Nesting Mortality of Granworous Birds. Warsaw. — & KENDEIOH, S. C. (eds.) 1977. Granworous Birds in Ecosystems. London. — - & SUMMERS-SMITH, J. D. (eds.) 1990. Granworous Birds in. the Agricultural landscape. Warsaw. REYNOEDS, J., & STILES, F. G. 1982. Distribucion y densidad de poblaciones del gorrion comun (Passer domesticus: Avcs: Ploceidae) en Costa Rica. Rai. Trap. Biol. 30: 65-77. SANO, M. 1990. [First record of House Sparrow in Japan.] Jap. J. Orn. 39: 33-35. SHARROCK, J. '1". R. 1993. The sparrows fall. Brit. Birds 86: 275. SiBEEY, S. C, & AHI.OJ.IIST, J. E. 1990. Phytogeny and Classification of Birds. New Haven & London. & MONROE, B. L. 1990. Distribution and Taxonomy of Birds of the World. New Haven & IjOiidon. SUMMERS-SMITH, I). 1963. The House Sparrow. London. 1980. House Sparrows down coal mines. Brit. Birds 73: 325-327. — 1988. The Sparrows. Calton. VEI<;.\, J. P. 1990. Infanticide by male and female House Sparrows. Anim. Behas. 39: 496-502. Voous, K. H. 1983. The Birds of the Netherlands Antilles. Zutphen. WETTON, J. H., & PARKIN, D. T. 1991a. Sperm competition and fertility in the House Sparrow. Pme. Int. Om. Congr. 20: 2435-2441. -• •— & 1991b. An association between fertility and cuckoldry in the House Sparrow Passer domeslkus. Proc. Roy. Soc. Icond. 245: 227-233. Woi.DKNDORF, K. 1981. Opvallencle afname van dc Huismus! Het Vogeljaar 27: 81.

DrJ. Denis- Summers-Smith, Merlewood, The Avenue, Guisborough, Cleveland TS14 SEE

The Sparrows (1988) and In Search of Sparrows (1992) by Denis Summers-Smith, both published by T. & A. D. Poyser, are available POSE EREE to BB subscribers this month through British BirdShop (see pull-out section in the centre of this issue).