Recommendations for depletion modelling of granivorous birds

səhifə	12/23
tarix	24.06.2016
ölçüsü	6.33 Mb.

1 ... 8 9 10 11 12 13 14 15 ... 23

¹ the calorific value of a related or un-named species is given (species name in brackets if known).
3.3 Relative frequency of occurrence of weed species in the field.
The relative abundance of weeds in the farmland environment is important for estimating the amount of food available to farmland birds. Ideally we need to know the typical densities of entire plants and seeds in order to estimate food availability, however this information was not readily available. Percentage cover was the most commonly used method, as it is an easy and quick way of estimating weed plant density, although plant cover may not be directly related to the abundance of entire plants or to seed production. Farm management practices (e.g. crop rotation, herbicide and tillage regimes) have an effect on weed abundance and diversity, and some of these factors were taken into consideration. There may also be spatial variation in the density of weeds within a field (e.g. Wilson & Aebischer 1995, Browne & Aebischer 2001), and the mean abundance of weeds was calculated separately for centre and edge positions. Data was compiled from several projects carried out in the United Kingdom (see Table 3.7). This information was forwarded to the modellers at UEA to faciltate estimates of typical weed densities in the farmland environment.
Table 3.7. Projects which provided data on the abundance of weeds and invertebrates in British farmland.

Project	Years	Number of sites	Project design	Data available
LINK - IFS	1992-1998	6 mixed arable farms: Manydown (Hampshire), Sacrewell & Boxworth (Cambridgeshire), Lower Hope (Hereford), Pathhead (Midlothian), High Mowthorpe (Nth Yorkshire)	7-9 paired blocks per site (~50ha per site). Each block subdivided into 2 plots to compare IFS (lower herbicide inputs) with conventional system	Relative abundance of weed spp. in autumn & winter (% cover in quadrats). Soil cores also taken for seeds. Pitfall trapping all year at all sites: 10 traps per plot. D-vac samples at Manydown only (7 fields): 10 samples at mid position, some edge
IEP	1999-2002	3 farms: Manydown, Lincoln, Castle Howard (Nth Yorkshire) 2 yrs sampling at each, starting with Manydown)	Four 1km² blocks at each farm	20 D-vac samples taken in summer in each block: 10 edge, 10 mid positions. Weed surveys at D-vac sites (% cover), seed samples taken
ARET	1992-	28 fields, mixed farming at Loddington (Leicestershire)		Weed quadrats (% cover). D-vac samples taken in each field: 2 edge, 2 mid positions
Sussex study	1970-	70-110 cereal fields on the South Downs (West Sussex)		Weed estimates done by Dick Potts (subjective scale for monocots & dicots - individual species listed but not separated). 1 D-vac sample taken in summer in each field: at edge & up to 10m into field

LINK IFS = LINK Integrated Farming System Project (see Holland et al. 1994 for details)

IEP = Indirect Effects of Pesticides Project (PN0925)

ARET = Allerton Research and Educational Trust (run by The Game Conservancy Trust)

Sussex study = study of cereal farms on the South Downs (run by The Game Conservancy Trust)
3.4 Spatial patterns of bird foraging.
A table of bird feeding locations was compiled using information from the literature and the RSPB website (2002) (see Table 3.8). Some species show a clear preference for a particular foraging location (e.g. the skylark Alauda arvensis is considered to be a mid-field feeder), while others forage in a variety of habitats within farmland. Birds were divided into three categories according to their foraging preferences:

Middle = forages within crop
Edge = forages in non-crop or margin habitats
Both = forages in crop and margin habitats

Table 3.8. Foraging preferences of birds in farmland and the crop types they are associated with.

Bird species	Foraging location	Crop type
Corn bunting	Middle	Cereals (barley), oilseed rape, root crops, stubbles
Lapwing	Middle	Cereals, stubbles
Quail	Middle	Cereals
Skylark	Middle	Cereals, oilseed rape, root crops (sugarbeet), sunflower, maize, linseed, lettuce, peas, stubbles
Yellow wagtail	Middle	Cereals, oilseed rape, root crops (potatoes)

Chaffinch	Edge	Cereals, oilseed rape, stubbles
Goldfinch	Edge	Orchards
Greenfinch	Edge	Cereals, oilseed rape, stubbles
Grey partridge	Edge	Cereals (wheat, barley), oilseed rape, stubbles
Linnet	Edge	Oilseed rape, stubbles
Red-legged partridge	Edge	Cereals, sugarbeet, carrots, beans
Tree sparrow	Edge	Cereals, turnips, stubbles

Cirl bunting	Both	Cereals, stubbles
Collared dove	Both	Cereals
House sparrow	Both	Cereals, stubbles
Reed bunting	Both	Cereals (wheat, barley), oilseed rape, stubbles
Rook	Both	Cereals, root crops (turnips, potatoes), stubbles
Stock dove	Both	Cereals (barley), stubbles
Stone curlew	Both	Roots crops (carrots, sugarbeet), kale
Turtle dove	Both	Cereals (wheat), peas
Woodpigeon	Both	Cereals, oilseed rape, stubbles
Yellowhammer	Both	Cereals (barley, wheat), oilseed rape, turnips, stubbles

3.5 Compare presence in diet with availability in the field according to feeding location (edge or centre).
In order to determine preference for certain taxa studies are required in which the proportion of a particular taxon in the diet as well as its abundance and availability in the field were measured. However, few dietary studies directly measured the abundance of food items in the field, and there were no studies that explicitly compared the presence in the diet with availability according to bird foraging locations. This is probably because estimates of weed abundance in a in a particular field are simple to obtain, but making measurements where the birds are actually feeding is more difficult. Moreover birds may foraging over a extensive area and it is therefore very difficult to relate foraging location to the measure of dietary intake. For example, if dietary intake is measured using faecal analysis then passage times and feeding location must be precisely known. Nevertheless of 100 studies on the diet of farmland birds, four considered the abundance of weeds in the field in relation to their presence in the diet: Browne & Aebischer (2001), Green (1978), Green (1980), and Vickerman & O’Bryan (1979).
For turtle doves the seeds indentified in the diet reflected those available where they were feeding (Browne & Aebischer, 2001). Green (1978) found that seeds of the common hemp-nettle (Galeopsis tetrahit) were eaten by skylarks slightly more than expected on the basis of their abundance at the soil surface, indicating a preference for this species. The rate at which skylarks tooks weed seeds from ploughed land increased with the density of seed available, and there was a strong correlation between the percentage of grain in the diet and its availability. Similarly, Green (1980) found that the proportions of seeds in the diet of skylarks increased as their abundance increased (r² = 0.614, p<0.01), but the percentage of seedlings in the diet did not increase with their density (r² = -0.373, P=0.09). Vickerman & O’Bryan (1979) revealed that some seeds were avoided by grey partridge chicks. No oat grains were eaten, even though relatively large areas of this cereal were grown in the Sussex study area, and few ryegrass (Lolium spp.) seeds were eaten even though these were the dominant ley grasses in the area.
3.6 Rank the value of different weed seeds.
Ideally, a final overall ranking of weed taxa incorporating all the factors above (Sections 3.1-3.5) would be determined for each bird species to identify which are the critical weed species for bird nutrition. However, this was not possible as there was insufficient information available for most of the bird species investigated in this project. The exception is that of the grey partridge (Perdix perdix), which has been the subject of many studies spanning a number of decades (e.g. Ford, Chitty & Middleton 1938, Hammer, Spärk & KØie 1958, Southwood & Cross 1969, Potts 1970, 1970b, Vickerman & O’Bryan 1979, Green 1984, Pulliainen 1984, Potts & Aebischer 1991, Itämies et al. 1996). Even so there is still insufficient information on the relative nutritional value of the most important weed seeds.
3.7 Construct a matrix of invertebrate-weed associations for invertebrate taxa considered to be of high value to farmland birds
The functional responses of foraging birds to variations in invertebrate prey density on weed species are not known, but an initial step was to examine the interactions between arable weeds and invertebrates which are important in the diet of farmland birds. Arable weeds provide a range of services or resources for invertebrates:

cover and shelter, particularly for epigeal predators (e.g. carabid and staphylinid beetles, Coleoptera: Carabidae and Staphylinidae; and spiders, Arachnida: Araneae)
a suitable microclimate by reducing moisture loss and moderating temperature and humidity levels
a food source for phytophagous (e.g. leaf bugs, Hemiptera: Homoptera) and spermophagous (eg. carabid beetles) insects, and therefore food for predatory arthropods which prey upon them

A literature search was carried out to examine the relationships between weed species and invertebrate taxa. Some of this research has already been carried out by Brown (2001). However, this is an extremely large task and is by no means complete. Interactions between arable weeds and invertebrates are highly complex, and very little is understood about the nature or importance of these associations for individual species. Brown (2001) remarks that “it is not generally known to what extent arthropod taxa are dependent on any specific plant species…indeed for many arthropods, vegetation density and structure may be more important than botanical composition.” Further information was added to the data compiled by Brown (2001) but because the reliability of these associations is uncertain this was not presented here.

3.8 References
Aebischer, N.J. & Ward, R.S. (1997) The distribution of corn buntings Miliaria calandra in Sussex in relation to crop type and invertebrate abundance. The Ecology and Conservation of Corn Buntings Miliaria calandra (eds P.F. Donald & N.J. Aebischer), pp. 124-138. Joint Nature Conservation Committee, Peterborough.

Aebischer, N.J., Blake, K.A., & Boatman, N.D. (1994) Field margins as habitats for game. Field Margins - Integrating Agriculture and Conservation (ed N.D. Boatman), pp. 95-104. British Crop Protection Council Monograph No. 58, BCPC Publications, Farnham.

Aerts, R. & Spaans, A.L. (1987) Habitat choice of feeding rooks Corvus frugilegus in southeastern Drenthe in the Netherlands. Limosa, 60, 123-128.

Beintema, A.J., Thissen, J.B., Tensen, D., & Visser, G.H. (1991) Feeding ecology of charadriiform chicks in agricultural grassland. Ardea, 79(1), 31-44.

Birkan, M., Serre, D., Skibnieski, S., & Pellard, E. (1992) Spring-summer home range, habitat use and survival of grey partridge (Perdix perdix) in a semi-open habitat. Gibier Faune Sauvage, 9, 431-442.

Boatman, N.D. (2001). Relationships between weeds, herbicides and birds. The impact of herbicides on weed abundance and biodiversity (eds J. Marshall, V. Brown, N.D. Boatman, P. Lutman & G. Squire), pp. 85-102. Report to DEFRA PN0940. Institute of Arable Crops Research, Barton Winscombe.

Brickle, N.W. (1997) The use of game cover and game feeders by songbirds in winter. The Brighton Crop Protection Conference – Weeds, pp. 1185-1190. British Crop Protection Council, Farnham.

Brooks, D., Bater, J., Jones, H., & Shah, P.A. (1995) The effect of organic farming regimes on breeding and winter bird populations. Invertebrate and weed seed food-sources for birds in organic and conventional farming systems. The Effect of Organic Farming Regimes on Breeding and Winter Bird Populations. BTO Research Report, 154. Part IV, 1-50. British Trust for Ornithology and Institute for Arable Crops Research - Rothamsted, Thetford.

Brown, V. K. (2001) The impact of herbicides on invertebrates. The impact of herbicides on weed abundance and biodiversity (eds J. Marshall, V. Brown, N.D. Boatman, P. Lutman & G. Squire), pp. 59-84. Report to DEFRA PN0940. Institute of Arable Crops Research, Barton Winscombe.

Browne, S.J. & Aebischer, N.J. (2001) The role of agricultural intensification in the decline of the turtle dove Streptopelia turtur. English Nature Research Report, 421, English Nature, Peterborough.

Burton, N.H.K., Watts, P.N., Crick, H.P.Q., & Edwards, P.J. (1999) The effects of preharvesting operations on reed buntings Emberiza schoeniclus nesting in oilseed rape Brassica napus. Bird Study, 46, 369-372.

Buxton, J.M., Crocker, D.R., & Pascual, J.A. (1998) Birds and farming: information for risk assessment. Unpublished report to DEFRA Pesticides Safety Directorate. Project No. M37, Central Science Laboratory, York.

Calladine, J.R., Buner, F., & Aebischer, N.J. (1997) The summer ecology and habitat use of the turtle dove: a pilot study. English Nature Research Report, 219, English Nature, Peterborough.

Chamberlain, D.E., Wilson, A.M., Browne, S.J., & Vickery, J.A. (1999) Effects of habitat type and management on the abundance of skylarks in the breeding season. Journal of Applied Ecology, 36(6), 856-870.

Chaney, K., Evans, A.D., & Wilcox, A. (1997) Effect of cropping practice on skylark distribution and abundance. The Brighton Crop Protection Conference – Weeds, pp. 1173-1178. British Crop Protection Council, Farnham.

Christensen, K.D., Falk, K., & Petersen, B.S. (1996) Feeding biology of Danish Farmland Birds: a literature study. DEPA Working Report, 12, 1-69. Danish Environmental Protection Agency, Denmark.

Coombs, F. (1978) The Crows. A study of the corvids of Europe. B.T. Batsford Ltd, London.

Cramp, S., Simmons, K.E.L., Gillmor, R., Hollom, P.A.D., Hudson, R., Nicholson, E.M., Ogilvie, M.A., Olney, P.J.S., Roselaar, C.S., Voous, K.H., Wallace, D.I.M., & Wattel, J. (1980) Handbook of the Birds of Europe, the Middle East and North Africa. The Birds of the Western Palaearctic. Vol. II Hawks to Bustards. Oxford University Press, Oxford.

Cummins, K.W. & Wuycheck, J.C. (1971) Calorific equivalents for investigation in ecological energetics. Mitteilung Internationale Vereinigung fuer Theoretische unde Amgewandte Limnologie, 18, 1-158.

Davies, N.B. (1977) Prey selection and social behaviour in wagtails (Aves: Motacillidae). Journal of Animal Ecology, 46, 37-57.

Donald, P.F. & Evans, A.D. (1994) Habitat selection by Corn Buntings Miliaria calandra in winter. Bird Study, 41, 199-210.

Donald, P.F. & Evans, A.D. (1995) Habitat selection and population size of Corn Buntings Miliaria calandra breeding in Britain in 1993. Bird Study, 42, 190-204.

Donald, P.F., Buckingham, D.L., Moorcroft, D., Muirhead, L.B., Evans, A.D., & Kirby, W.B. (2001) Habitat use and diet of skylarks Alauda arvensis wintering on lowland farmland in southern Britain. Journal of Applied Ecology, 38, 536-547.

Ebbinge, B., Canters, K., & Drent, R. (1975) Foraging routines and estimated daily food intake in Barnacle Geese wintering in the northern Netherlands. Wildfowl, 20, 5-19.

Eybert, M.C. & Constant, P. (1992) Validity of faecal sac analysis for studies on the diet of nestlings of the European linnet (Carduelis cannabina). In French with English summary. Canadian Journal of Zoology, 70, 2171-2177.

Eybert, M.C., Constant, P., & Lefeuvre, J.C. (1995) Effects of changes in agricultural landscape on a breeding population of linnets Acanthis cannabina L. living in adjacent heathland. Biological Conservation, 74(3), 195-202.

Feare, C.J., Dunnet, G.M., & Patterson, I.J. (1974) Ecological studies of the rook (Corvus frugilegus) in North-East Scotland: food intake and feeding behaviour. Journal of Applied Ecology, 11, 867-896.

Fischer, S. & Schops, A. (1997) Habitat selection by corn buntings Miliaria calandra in north-east Germany - the results of preliminary studies. The Ecology and Conservation of Corn Buntings Miliaria calandra.174-177. Joint Nature Conservation Council, Peterborough.

Galbraith, H. (1989) The diet of lapwing Vanellus vanellus chicks on Scottish farmland. Ibis, 131, 80-84.

Gibb, J. (1957) Food requirements and other observations on captive tits. Bird Study, 4, 207-215.

Gillings, S. & Fuller, R.J. (2001) Habitat selection by skylarks Alauda arvensis wintering in Britain in 1997/98. Bird Study, 48, 293-307.

Gillings, S. & Watts, P.N. (1997) Habitat selection and breeding ecology of the corn buntings Miliaria calandra in the Lincolnshire Fens. The Ecology and Conservation of Corn Buntings Miliaria calandra (eds P.F. Donald & N.J. Aebischer), pp. 139-150. Joint Nature Conservation Committee, Peterborough.

Glück, E.E. (1985) Seed preference and energy intake of Goldfinches Carduelis carduelis in the breeding season. Ibis, 127, 421-429.

Green, R.E. & Tyler, G.A. (1989) Determination of the diet of the stone curlew (Burhinus oedicnemus) by faecal analysis. Journal of the Zoological Society of London, 217, 311-320.

Green, R.E. (1978) Factors affecting the diet of farmland skylarks, Alauda arvensis. Journal of Animal Ecology, 47, 913-928.

Green, R.E. (1980) Food selection by skylarks and grazing damage to sugar beet seedlings. Journal of Applied Ecology, 17, 613-630.

Green, R.E. (1984) The feeding ecology and survival of partridge chicks (Alectoris rufa and Perdix perdix) on arable farmland in East Anglia. Journal of Applied Ecology, 21, 817-830.

Gregory, R.D., Wilkinson, N.I., Noble, D.G., Robinson, J.A., Brown, A.F., Hughes, J., Procter, D., Gibbons, D.W., & Galbraith, C.A. (2002) The population status of birds in the United Kingdom, Channel Islands and Isle of Man: an analysis of conservation concern 2002-2007. British Birds, 95, 410-448.

Grodzinski, W. & Sawicka-Kapusta, K. (1970) Energy values of tree-seeds eaten by small mammals. Oikos, 21, 52-58.

Holland, J.M., Frampton, G.K., Çilgi, T. & Wratten, S.D (1994) Arable acronyms analysed – a review of integrated arable farming systems research in Western Europe. Annals of Applied Biology, 125, 399-438.

Holland, J. M., Southway, S. E., Ewald, J. A., Birkett, T., & Begbie, M. (2002) Invertebrate chick food for farmland birds: spatial and temporal variation in different crops. Aspects of Applied Biology, 67, 27-34.

Inglis, I.R., Isaacson, A.J., Smith, G.C., & Thearle, R.J.P. (1997) The effect on the woodpigeon (Columba palumbus) of the introduction of oilseed rape into Britain. Agriculture, Ecosystems and Environment, 61(2-3), 113-121.

Inglis, I.R., Isaacson, A.J., Thearle, R.J.P., & Westwood, N.J. (1990) The effects of changing agricultural practice upon woodpigeon Columba palumbus numbers. Ibis, 132, 262-272.

Itämies, J., Putaala, A., Pirinen, M., & Hissa, R. (1996) The food composition of grey partridge chicks Perdix perdix in central Finland. Ornis Fennica, 73(1), 27-34.

Jenny, M. (1990) Diet-ecology of the Skylark Alauda arvensis in an intensively cultivated agroecosystem in the Swiss Midlands. In German. Der Ornithologische Beobachter, 87, 31-53.

Karasov, W.H. (1990) Digestion in birds: chemical and physiological determinants and ecological implications. Avian Foraging Theory: methodology and applications (eds M.L. Morrison, C.J. Ralph, J. Verner, & J.R. Jehl), pp. 391-415. Studies in Avian Biology, 14. Cooper Ornithological Society, Camarillo, California.

Kendleigh, S.C. & West, G.C. (1965) Calorific values of plant seeds eaten by birds. Ecology, 46, 553-555.

Mason, C.F. & MacDonald, S.M. (2000) Corn Bunting Miliaria calandra populations, landscape and land-use in an arable district of eastern England. Bird Conservation International, 10(2), 169-186.

Mason, C.F. & MacDonald, S.M. (2000) Influence of landscape and land-use on the distribution of breeding birds in farmland in eastern England. Journal of Zoology, 251(3), 339-348.

Miller, D.F. (1958) Composition of cereal grains and forages. Publication 585, National Academy of Sciences, National Research Council, Washington D.C.

Moorcroft, D., Whittingham, M.J., Bradbury, R.B., & Wilson, J.D. (2002) The selection of stubble fields by wintering granivorous birds reflects vegetation cover and food abundance. Journal of Applied Ecology, 39, 535-547.

Moreby, S.J. (1988) An aid to the identification of arthropod fragments in the faeces of gamebird chicks (Galliformes). Ibis, 130, 519-526.

Moreby, S.J., Southway, S. & Boatman, N.D. (1999) The importance of the crop edge compared to the mid-field, in providing invertebrate food for farmland birds. Aspects of Applied Biology, 54, 217-222.

Moreby, S.J. & Stoate, C. (2000) A quantitative comparison of neck-collar and faecal analysis to determine passerine nestling diet. Bird Study, 47, 320-331.

Morris, A.J., Whittingham, M.J., Bradbury, R.B., Wilson, J.D., Kyrkos, A., Buckingham, D.L., & Evans, A.D. (2001) Foraging habitat selection by yellowhammers (Emberiza citrinella) nesting in agriculturally contrasting regions in lowland England. Biological Conservation, 101(2), 197-210.

Murton, R.K., Westwood, N.J., & Isaacson, A.J. (1964) The feeding habits of the woodpigeon Columba palumbus, stock dove C. oenas and turtle dove Streptopelia turtur. Ibis, 106, 174-188.

Odderskaer, P., Prang, A., Poulsen, J.G., Andersen, P.N., & Elmegaard, N. (1997) Skylark (Alauda arvensis) utilisation of micro-habitats in spring barley fields. Agriculture, Ecosystems and Environment , 62(1), 21-29.

Potts, G.R. & Aebischer, N.J. (1991) Modelling the population dynamics of the Grey Partridge: conservation and management. Bird Population Studies: their relevance to conservation and management (eds C.M. Perrins, J-D. Lebreton & G.J.M. Hirons), pp. 373-390. Oxford University Press, Oxford.

Potts, G.R. (1970) Recent changes in the farmland fauna with special reference to the decline of the grey partridge. Bird Study, 17, 145-166.

Potts, G.R. (1970b) Studies on the changing role of weeds in the genus Polygonum in the diet of the partridge Perdix perdix L. Journal of Applied Ecology, 7, 567-576.

Poulsen, J.G. & Aebischer, N.J. (1995) Quantitative comparison of two methods of assessing diet of nestling skylarks (Alauda arvensis). The Auk, 112(4), 1070-1073.

Poulsen, J.G., Sotherton, N.W., & Aebischer, N.J. (1998) Comparative nesting and feeding ecology of skylarks Alauda arvensis on arable farmland in southern England with special reference to set-aside. Journal of Applied Ecology, 35, 131-147.

Pulliainen, E. (1984) Changes in the composition of the autumn food of Perdix perdix in west Finland over 20 years. Journal of Applied Ecology, 21, 133-139.

Robinson, R.A. & Sutherland, W.J. (1997) The feeding ecology of seed-eating birds on farmland in winter. JNCC Report, 13, 162-169. Joint Nature Conservation Council, Peterborough.

RSPB website (2002) Royal Society for the Protection of Birds. www.rspb.org.uk/features/default.asp

Shuman, T.W., Robel, R.J., Dayton, A.D., & Zimmerman, J.L. (1988) Apparent metabolizable energy contents of foods used by Mourning Doves. Journal of Wildlife Management, 52(3), 481-483.

Southwood, T.R.E. & Cross, D.J. (1969) The ecology of the partridge. III. Breeding success and the abundance of insects in natural habitats. Journal of Animal Ecology, 38, 497-509.

Stoate, C. & Szczur, J. (1997) Seasonal changes in habitat use by yellowhammers (Emberiza citrinella). Brighton Crop Protection Conference – Weeds, pp. 1167-1172. British Crop Protection Council, Farnham.

Stoate, C., Moreby, S.J., & Szczur, J. (1998) Breeding ecology of farmland Yellowhammers Emberiza citrinella. Bird Study, 45, 109-121.

Toepfer, S. & Stubbe, M. (2001) Territory density of the skylark (Alauda arvensis) in relation to field vegetation in central Germany. Journal für Ornithologie, 142(2), 184-194.

US National Research Council (1985) Nutritional requirements of sheep. US National Research Council, Washington DC.

Vickerman, G.P. & O'Bryan, M. (1979) Partridges and insects. The Game Conservancy Annual Review, 10, 35-43.

Vickery, J.A., Carter, N., & Fuller, R.J. (2002) The potential value of managed cereal field margins as foraging habitats for farmland birds in the UK. Agriculture, Ecosystems and Environment, 89(1-2), 41-52.

Watson, A. & Rae, R. (1997) Preliminary results from a study of habitat selection and population of corn buntings Miliaria calandra in north-east Scotland. The Ecology and Conservation of Corn Buntings Miliaria calandra (eds P.F. Donald & N.J. Aebischer), pp. 115-123. Joint Nature Conservation Committee, Peterborough.

Watson, A. & Rae, R. (1997) Some effects of set-aside on breeding birds in northeast Scotland. Bird Study, 44, 245-251.

Whittingham, M.J., Bradbury, R.B., Wilson, J.D., Morris, A.J., Perkins, A.J., & Siriwardena, G.M. (2001) Chaffinch Fringilla coelebs foraging patterns, nestling survival and territory distribution on lowland farmland. Bird Study, 48, 257-270.

Wilson, P. J. & Aebischer, N. J. (1995) The distribution of dicotyledonous arable weeds in relation to distance from the field edge. Journal of Applied Ecology, 32, 295-310.

Wilson, J.D., Evans, J., Browne, S.J., & King, J.R. (1997) Territory distribution and breeding success of skylarks Alauda arvensis on organic and intensive farmland in southern England. Journal of Applied Ecology, 34, 1462-1478.

Wilson, J.D., Taylor, R., & Muirhead, L.B. (1996) Field use by farmland birds in winter: an analysis of field type preferences using resampling methods. Bird Study, 43, 320-332.

Wilson, J.D.; Arroyo, B.E.; and Clark, S.C. (1996). The diet of bird species of lowland farmland: a literature review. A report to the Department of the Environment and English Nature. University of Oxford, Oxford.

3.9 References used to assess bird diet (Tasks 3.1 & 5.1)

1 ... 8 9 10 11 12 13 14 15 ... 23