The tree sparrow is patchily distributed on farmland across Britain and Ireland, being scarcer in the uplands, and the far north and west. The main populations are now found across the Midlands, southern and eastern England, with the species almost absent from the south-west, Wales and the north-west. The tree sparrow appears to undergo irregular fluctuations in numbers. In Britain, there was a high population from the 1880s to the 1930s, but numbers then decreased to a low point around 1950, around which time it became extinct in Ireland. Numbers then increased again from 1960 to 1978, possibly due to an influx of birds from mainland Europe. However, based on the Common Bird Census, there was a decline of 85% in numbers in Britain between the two breeding atlas periods (1968-72 and 1988-91), the largest decline of any common species during this period. The tree sparrow also decreased in range by 20% over the same period, with particular losses in Wales and Scotland. The species is still common and widespread across mainland Europe with population trends differing between countries. Populations are mainly sedentary but large-scale autumnal movements occasionally occur, particularly from the more northerly parts of the range.
The tree sparrow is protected under the Wildlife and Countryside Act 1981, Wildlife (Northern Ireland) Order 1985 and EC Birds Directive.
Current factors causing loss or decline
Little is known about the factors affecting numbers of tree sparrows, but their recent decline has occurred at the same time as decreases in the numbers and/or ranges of other farmland birds which share its diet of grass, wildflower and cereal seeds, and also feed their young on insects. It is therefore likely that its decline is due to changing agricultural practices, particularly the increased use of herbicides; the shift from spring-sown to autumn-sown crops and the consequent loss of winter stubble fields; the more intensive management of grassland; and the general reduction of habitat diversity on farmland due to the loss of mixed farming and increased specialisation.
As a colonial or semi-colonial hole-nesting species, the availability of nest sites may be a limiting factor, and the fact that nest boxes are readily occupied supports this. The loss of elm trees from lowland Britain during the late 1970s and 1980s would doubtless have removed large numbers of potential nest sites from favoured areas.
Little direct conservation work for the tree sparrow has been carried out, although nest-box schemes in a number of areas have been implemented.
Rotational set-aside will have benefited the species, although this has been significantly reduced in area in recent years. New prescriptions encouraging the growth of spring-sown cereals and retention of winter stubbles in the South Downs ESA, and the pilot Arable Stewardship Scheme, should also benefit the tree sparrow.
Action plan objectives and targets
In the short term, halt or reverse the decline in numbers of the tree sparrow by the year 2003 so that the Breeding Bird Survey index is at least at 1996 levels.
In the long term see a sustained recovery in numbers so that the BBS index is at least 50% higher than 1996 levels by 2008.
Expand the range from that of 1996, as measured by the frequency in random BBS squares, by 2008.
Proposed actions with lead agencies
Policy and legislation
Take account of the need to recover tree sparrow and other farmland bird populations when developing agricultural policy and CAP reform; consider how to extend the Arable Stewardship Scheme if the pilot is successful, and how to substitute for the benefits of set-aside, if this is further reduced or abolished. Retention of appropriately managed hedgerow trees and farm woodland should be encouraged. (ACTION: DANI, FA, MAFF, SOAEFD, WOAD)
Where appropriate, incorporate new management prescriptions when reviewing agri-environment schemes, especially ESAs, Countryside Stewardship, Tir Cymen and Countryside Premium Scheme, in order to reverse some of the recent changes in farm management outlined in Section 2. (ACTION: CCW, DANI, MAFF, SOAEFD, WOAD)
Seek uptake of a more cautious and targeted use of pesticides and fertilisers on farmland to reduce the impacts on potential food sources for the tree sparrow. This could include encouraging integrated crop management, organic farming and the more widespread adoption of initiatives such as the recently begun Scottish 'TIBRE' project. (ACTION: DANI, MAFF, SOAEFD, WOAD)
Site safeguard and management
Consider implementing site safeguard measures for a small number of large tree sparrow colonies (ie those in excess of 20 pairs). (ACTION: CCW, EHS, NE, SNH)
Undertake management measures for tree sparrows within protected areas (especially nature reserves) and, where possible, promote them on adjoining farmland. Measures will include nest-box schemes, retention of dead trees and provision of winter feeding habitat. (ACTION: CCW, EHS, NE, SNH)
Species management and protection
Promote further advice to land managers on management for tree sparrows as one of a suite of farmland birds and update that advice in the light of new policies and research findings. (ACTION: DANI, MAFF, SOAEFD, WOAD)
Promote effective management of set-aside for breeding and wintering birds, including the tree sparrow. (ACTION: DANI, MAFF, SOAEFD, WOAD).
Future Research and Monitoring
Carry out an historical review of the species, including analysis of existing BTO Nest Record Cards, in order to investigate the possible reasons for decline. (ACTION: CCW, EHS, NE, JNCC, SNH)
Undertake an autecological study of the tree sparrow in order to determine its requirements and investigate the factors causing the population decline. (ACTION: CCW, EHS, NE, SNH)
Ensure appropriate monitoring of numbers through continuation of the BTO/JNCC/RSPB Breeding Bird Survey and consider the setting up of an equivalent survey to monitor winter populations. (ACTION: CCW, EHS, NE, JNCC, SNH)
Communications and Publicity
As appropriate, use the tree sparrow as an example when highlighting the issue of declining farmland birds. (ACTION: CCW, EHS, NE, SNH)
Promote a change in perception of wild plants on farmland as essential food sources for seed-eating farmland birds, rather than as 'weeds'. (ACTION: DANI, MAFF, SOAEFD, WOAD)
Links with other action plans
Originally published in: UK Biodiversity Group Tranche 2 Action Plans - Volume I: Vertebrates and vascular plants (June 1998, Tranche 2, Vol I, p93)
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