De Laet J, Summers-Smith JD. The status of the urban house sparrow Passer domesticus in North-Western Europe: a review. J Ornithol 148: S275-S278

Abstract

The house sparrow Passer domesticus is unique among wild birds in its close association with, indeed virtual dependence on, man. Not only in the agricultural environment, where presumably this association first evolved, but also in built-up areas. It would be expected that, with man's dominance of the world, the future would be bright for the bird, but it is now becoming evident that this is not the case, particularly in the highly developed region of western Europe. In Britain, the Common Bird Census launched by the British Trust for Ornithology in 1962 provided such a basis. This enquiry showed a major decline in the house sparrow population in farmland beginning in the latter half of the twentieth century, though this now appears to have stabilised, albeit at a lower level. This decline, which also affected a number of other farmland species, has been well studied and is now accepted to be the result of the intensification of agricultural practices that have led to a reduction in the availability of food. The spillage of oats from the nosebags of horses and the presence of undigested seeds in the droppings must have provided a major source of food for urban house sparrows. Although not well recorded, there is little doubt that the replacement of the horse by the internal combustion engine must have resulted in a significant decrease in urban house sparrows in the 1920s, though not withstanding it still remained a common bird of built-up areas. This habitat has been largely neglected by ornithologists and it was the general public that first drew attention to a major decline in town centres, so that by the end of the twentieth century it had become virtually extinct in the centres of a number of major European cities, though apparently still common in others. Unlike the farmland decline, the urban decline appears to be proceeding at an increasing rate and is showing no sign of stabilising. The urban decline has been the subject of much speculation, but the reason(s) is/are not properly understood. This is clearly an interesting ornithological question. The aim of this paper is to provide a summary of the present status of the house sparrow in urban areas in north-western Europe and to identify those areas of research that will provide the necessary evidence to understand what is going on.

Full text

REVIEW
The status of the urban house sparrow Passer domesticus
in north-western Europe: a review
J. De Laet ÆJ. D. Summers-Smith
Received: 18 February 2007 / Revised: 17 May 2007 / Accepted: 18 May 2007 / Published online: 11 September 2007
Dt. Ornithologen-Gesellschaft e.V. 2007
Abstract The house sparrow Passer domesticus is unique
among wild birds in its close association with, indeed
virtual dependence on, man. Not only in the agricultural
environment, where presumably this association first
evolved, but also in built-up areas. It would be expected
that, with man’s dominance of the world, the future would
be bright for the bird, but it is now becoming evident that
this is not the case, particularly in the highly developed
region of western Europe. In Britain, the Common Bird
Census launched by the British Trust for Ornithology in
1962 provided such a basis. This enquiry showed a major
decline in the house sparrow population in farmland
beginning in the latter half of the twentieth century, though
this now appears to have stabilised, albeit at a lower level.
This decline, which also affected a number of other
farmland species, has been well studied and is now
accepted to be the result of the intensification of agricul-
tural practices that have led to a reduction in the
availability of food. The spillage of oats from the nosebags
of horses and the presence of undigested seeds in the
droppings must have provided a major source of food for
urban house sparrows. Although not well recorded, there is
little doubt that the replacement of the horse by the internal
combustion engine must have resulted in a significant
decrease in urban house sparrows in the 1920s, though not
withstanding it still remained a common bird of built-up
areas. This habitat has been largely neglected by orni-
thologists and it was the general public that first drew
attention to a major decline in town centres, so that by the
end of the twentieth century it had become virtually extinct
in the centres of a number of major European cities, though
apparently still common in others. Unlike the farmland
decline, the urban decline appears to be proceeding at an
increasing rate and is showing no sign of stabilising. The
urban decline has been the subject of much speculation, but
the reason(s) is/are not properly understood. This is clearly
an interesting ornithological question. The aim of this
paper is to provide a summary of the present status of the
house sparrow in urban areas in north-western Europe and
to identify those areas of research that will provide the
necessary evidence to understand what is going on.
Keywords Decline House sparrow Status 
Urban environment
Introduction
Of all wild birds none is more closely associated with man
than the house sparrow Passer domesticus. Twenty, even
10 years ago, it was unimaginable that the house sparrow
would be the focus for discussion at an international
ornithological or environmental conference.
Today, the status of the house sparrow, and more spe-
cifically the urban house sparrow, is the subject of study by
several national and regional ornithological organisations
in several European countries. Even outside the European
Union, the house sparrow now receives more attention than
in earlier days.
Although this paper is primarily concerned with the
decline of the house sparrow in the urban environment, we
Communicated by F. Bairlein.
J. De Laet (&)
Terrestrial Ecology Unit, UGhent,
K.L. Ledeganckstr. 35, B-Ghent, Belgium
e-mail: famtrapp@scarlet.be
J. D. Summers-Smith
79 Thames Avenue, Guisborough TS14 8AJ, UK
123
J Ornithol (2007) 148 (Suppl 2):S275–S278
DOI 10.1007/s10336-007-0154-0

would like to set the scene in this introductory presentation
by discussing the overall status of the bird. There are two
reasons for this:
•Much more and better quantitative data are available
for the farmland habitat
•House sparrows are extremely sedentary birds, the
majority living out their lives within an ambit of 1–
2 km (Summers-Smith 1963). Moreover, evidence
from ringing, both recoveries of birds with numbered
rings and also sightings of colour-ringed ones, suggest
that there is little interchange between the farmland
birds and those living in built-up areas (Summers-
Smith and Thomas 2002).
Although the species has declined significantly in both the
rural and the built-up environments, we believe that there is
little exchange of birds between these environments and
feel it is prudent at this stage to treat these declines as
separate phenomena. Our discussion is primarily related to
the situation in north-western Europe and more particularly
to Belgium and Britain.
Results and discussion
It is difficult to put numbers on the house sparrow popu-
lations in different European regions prior to the
development of modern scientific field ornithology in the
twentieth century; though there is little doubt that it
became a common bird following the advent of ‘‘high
farming’’ with its intensive mixed farming methods in the
eighteenth century. Perceived as pests that devoured grain
and worried livestock, house sparrows became the declared
enemies of farmers.
Throughout the eighteenth and nineteenth centuries,
parishes had ‘‘sparrow clubs’’, which paid out money for
dead birds and eggs (Clark 2002). Until the 1870s, monies
from church tithes, set aside for ‘‘pious and charitable uses’’,
were dispensed in exchange for sparrow heads. Although
‘‘sparrow money’’ had largely disappeared from parish
accounts by 1870, sparrow clubs, as private initiatives,
continued to offer prizes well into the twentieth century.
Changes in farmland were not the only spurs to growth
in sparrow populations. Unlike other birds, sparrows pos-
itively prospered from the growth of towns. Between 1830
and 1900, the area of agricultural acreage fell in the UK by
more than 0.5 million ha (O’Connor and Shrubb 1986).
House sparrows have always lived in close contact with
man in built-up habitats. Increasing urbanisation with a
horse-drawn transport provided a major source of food for
the house sparrows in the spillage of oats from the nose-
bags and undigested seed in the droppings. This, together
with generally poor street hygiene, provided a habitat of
growing importance for the house sparrow. Nevertheless,
there is a problem in interpreting what is going on in the
urban environment because of the inadequacy and lack of
historical data.
It is assumed that the first urban decline of the house
sparrow was the result of the replacement of the horse by
the automobile as a means of transport (Summers-Smith
2005). Not only did this remove a great source of food from
the sparrow, but the faster moving traffic made the streets
less safe to feed in (Bergtold 1921) and were presumably
responsible for a disproportional mortality of naı
¨ve young
birds.
This was especially remarked in the United States (e.g.
Bergtold 1921) and the Maritime Provinces of Canada (A.J.
Erskine, unpublished manuscript), but is also suggested by
the change in the Kensington Garden population counts
between 1925 and 1948 (Fig. 1).
In 1963, one of the authors (J.D.S.S.) predicted that the
future looked bright for the house sparrow with man’s
dominance of the globe and the increasing amount of built-
up land, the preferred habitat for the bird. He is now the
first to admit how wrong he was.
Figure 2shows the Population Index for the bird in
Great Britain from 1970 to the present day. This is based
on the Common Bird Census (CBC) run by the British
Trust for Ornithology (BTO) and gives an indication of the
abundance of the bird. Admittedly, the numbers did
increase until the late 1970s, as Summers-Smith had pre-
dicted, but then, without warning, numbers began to
decrease and, by 1997, had fallen by about 60%. Since then
numbers appear to have stabilised (Sanderson 2001).
The CBC results come predominantly from farmland
and the decline has been attributed to changes in farming
practice that have made this habitat less attractive for the
bird. A study by the BTO suggests that the main reason for
the decline has been a decrease in survival (Crick et al.
2002).
This does not, however, tell us the whole story. The
CBC has its limitations and does not really provide us with
Fig. 1 Autumn counts of house sparrows Passer domesticus in
Kensington Gardens, London between 1925 and 2002
S276 J Ornithol (2007) 148 (Suppl 2):S275–S278
123

information on what is happening in the built-up environ-
ment, the most important habitat as far as the house
sparrow is concerned. The urban situation, however, is
much less clear than that for the farmland. The only long
term trend analysis comes from the autumn counts in
Kensington Gardens shown in Fig. 1. These were started in
1925 by Max Nicholson, who died at the age of 98 years in
2003, and have been repeated at very irregular intervals up
to the present. After the dramatic fall in the 1920s, when
the horse was replaced by the internal combustion engine,
there was a period of gradual decline up to the 1980s, when
the bird went into freefall. It has now virtually disappeared.
Other irregular counts in different parts of London are
consistent with the Kensington Garden counts (R.L. Bland,
personal commmunication).
In Belgium, a bird watcher counted, over a period of
more than 50 years, the breeding birds in his surroundings
in Kortrijk (100 ha) (De Bethune 2004). He estimated 100–
150 breeding house sparrow pairs in 1950, but only 10–20
pairs in 2000.
In the absence of repeat counts giving trend data, the
densities of house sparrows from a number of urban cen-
suses carried out in London, Glasgow, Edinburgh and two
from outside the UK, Dublin and Hamburg, are plotted in
Fig. 3. This shows that the decline has not been confined to
Britain (Summers-Smith 2005). These results suggest a
decline of over 90% in the last 25 years, much more severe
than that in farmland.
The urban decline is not only more severe, but appears
to have started later and, unlike the countryside one, is still
going on, perhaps even at an accelerating rate. This sug-
gests that we are dealing with two separate sub-
populations: one associated with farmland (Fig. 2), the
other with built-up areas (Fig. 3). Though it is not as
simple as that. Studies from small rural towns suggest that
the decline, if any, has been much less severe than in both
the urban centres and in farmland (Fig. 4). This implies we
have to deal with three different environments.
Nevertheless, the situation is even more complicated
than is suggested by the above generalisations. The situa-
tion in large towns is by no means simple. While there have
been dramatic declines, almost to the point of extinction, in
the centre of London, Glasgow (Summers-Smith 1999),
Edinburgh (Dott and Brown 2000), Dublin (Summers-
Smith, personal observation), Hamburg (Mitschke et al.
1999), Ghent, Antwerp and Brussels (De Laet 2004), there
appears to have been no comparable decline in Manchester
(J. Smith, quoted by Prowse 2002), Berlin (Bo
¨hner et al.
2003), and Paris (McCarthy 2000). It is even remarkable
that beautiful pictures of the close association between
house sparrows and man still come from central parts of
Paris, such as the Notre-Dame and the Sacre Coeur. It is no
longer possible to take such photographs in other city
centres, like London, Rotterdam, Ghent, Brussels and
Antwerp (personal observations). Moreover, data from the
BTO’s Breeding Bird Survey, covering the period 1994–
2000, suggest that, while there has been an overall decline
of house sparrows in England, the species has actually
increased in Scotland and Wales (Crick et al. 2002).
While the separation of the built-up habitat into large
town centres and small rural towns/outer suburbs is a
convenient generalisation, the urban habitat is by no means
0
20
40
60
80
100
120
140
160
180
0791
3791
6791
9791
2891
5891
88
91
19
91
49
91
7991
Population index
Fig. 2 Population index based on the Common Bird Census counts
run by the BTO since 1970
Fig. 3 House sparrow densities in urban areas. Kensington Gardens
(blocks), large town centers (crosses) and small rural towns (dots) Fig. 4 House sparrow densities in small rural towns
J Ornithol (2007) 148 (Suppl 2):S275–S278 S277
123

uniform and detailed studies have shown that the decline in
built-up habitats has been patchy. The patchiness of the
decline in London is well demonstrated by the Summer
2002 Survey in Britain organised by the Royal Society for
the Protection of Birds study (RSPB 2003).
Many countries produce, with the help of bird-watchers,
national counts of their breeding birds in atlases. In most of
these, urban centres are neglected and shown as blank spots
Most atlases work with European UTM plots For example,
in Belgium 5 ·5 km plots are used. For each plot, eight 1-
km squares are randomly chosen.
These methods have serious limitations for the investi-
gation of the status of the house sparrow.
•No distinction between urban, suburban and rural
habitats.
•The working scale is to big.
So finally we shall end with some recommendations:
•The recent evidence for a selective decline of the house
sparrow in our urban centres is very compelling, but the
data are by no means statistically robust. There is an
urgent need for more and better data and close cooper-
ation between the different investigating countries.
•There is a need for properly funded research into urban
house sparrow decline.
•Birds are recognised as indicators of the ‘‘quality of
life’’. What does a 95% decline of house sparrows tells
us about the quality of life in our urban centres? We
need to know.
•Is the house sparrow the present day equivalent of the
‘miner’s canary’? Is it telling us that something nasty is
going on in our towns that might even affect us? This
requires investigation.
Acknowledgments J.D.L. wishes to thank the Terrestrial Ecology
Unit of the University of Ghent and especially Prof. Dr Luc Lens for
his support and interest in the House Sparrow decline. Also, Ak-
tiekomitee ter Beveiliging van het Leefmilieu op de LinkerOever en
het Waasland vzw who give me the opportunity to put some time into
the House Sparrow investigation.
References
Bergtold WH (1921) The English sparrow (Passer domesticus) and
the motor vehicle. Auk 38:244–250
Bo
¨hner J, Schulz W, Witt K (2003) Bestand und lebensraumspezifi-
sche Dichten des Haussperlings in Berlin. Artenschutzreport
(Sonder-)Heft 14:13–17
De Bethune G (2004) De stille lente: Vijftig jaar evolutie van de
broedvogels in een kilometerhok bij Kortrijk. Natuur Oriolus
70:153–158
Clark JFM (2002) The Irishmen of birds.History Today, 16–18
October 2000
Crick HPQ, Robinson RA, Appleton GF, Clark N, Rickard AD (eds)
(2002) An investigation into the causes of decline of starlings
and house sparrows in Great Britain. BTO Research Report No.
290. British Trust for Ornithology, Thetford, UK
Dott HEM, Brown AW (2000) A major decline of house sparrows in
central Edinburgh. Scott Birds 21:61–68
De Laet J (2004) De Huismus: verontrustend nieuws, in de steden is
het niet vijf maar Twee voor twaalf. Mens Vogel 42:238–245
McCarthy M (2000) Where have all the sparrows gone? The
Independent Newpaper, 18 March 2000
Mitschke A, Geissler H-H, Baumung S, Andersen L (1999) Ornitho-
logische Jahresbericht 1996 und 1997 fu
¨r das Hamburger
Berichtsgebiet. Hamburger Avifaun Beitr 30:129–204
O’Connor RJ, Shrubb M (1986) Farming and birds. Cambridge
University Press, Cambridge
RSPB (2003) Where have all our sparrows gone? Survey Report
London 2002. Royal Society for the Protection of Birds, Sandy,
UK
Sanderson RF (2001) Further declines in an urban population of house
sparrows. Br Birds 94:507
Smith J, quoted by Prowse A (2002) The urban decline of the house
sparrow. Br Birds 95:144–146
Summers-Smith JD (1963) The house sparrow. Collins, London
Summers-Smith JD (1999) Current status of the house sparrow in
Britain. Br Wildl 10:381–386
Summers-Smith JD (2005) Changes in the house sparrow population
in Britain. Int Stud Sparrows 30:23–37
Summers-Smith JD, Thomas DK (2002) House sparrow. In: Wern-
ham C, Toms M, Marchant M, Clark J, Siriwandera G, Baillie S
(eds) The migration atlas: movements of birds in Britain and
Ireland. Poyser, London, pp 633–634
S278 J Ornithol (2007) 148 (Suppl 2):S275–S278
123