Effect of sward type and management on diversity of upland birds

Published source details Vale J.E. & Fraser M.D. (2007) Effect of sward type and management on diversity of upland birds. Pages 333-336 in: J. Hopkins, A.J. Duncan, D.I. McCracken, S. Peel & J.R.B. Tallowin (eds.) High value grassland: Providing biodiversity, a clean environment and premium products. British Grassland Society Occasional Symposium No.38. British Grassland Society (BGS), Reading.
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This study is summarised as evidence for the following.

	Action	Category
	Employ grazing in non-grassland habitats Action Link
	Employ areas of semi-natural habitat for rough grazing (includes salt marsh, lowland heath, bog, fen) Action Link
	Reduce grazing intensity Action Link
	Employ grazing in artificial grasslands/pastures Action Link
	Reduce grazing intensity on grassland (including seasonal removal of livestock) Action Link

Employ grazing in non-grassland habitats

A replicated trial in the UK (Vale & Fraser 2007) found that songbirds and invertebrate-feeding birds were recorded more often on semi-natural rough grazing than on upland improved pasture, but the opposite was true for crows. Bird numbers and species were recorded in plots of improved upland pasture grazed by cattle and sheep (ten with and ten without the seasonal removal of grazing in summer) and in plots of semi-natural rough grazing grazed by cattle from June to September (six replicates). The proportion of surveys where songbirds and invertebrate feeders were recorded was greater on semi-natural rough grazing than on improved pasture. However, the effect on the number of individuals varied over the year. The number of birds of invertebrate-feeding species was greater on semi-natural grassland between May and July (338 birds, compared to 52 and 41 on improved treatments, with and without seasonal grazing removal), but greater on improved treatments between October and January (5,833 and 1,458 birds on improved treatments compared to 606 birds on semi-natural grassland). There were fewer crows on semi-natural rough grazing plots at all times of year, but the difference was greatest during July to September (16 birds on rough grazing compared to 496 and 77 on improved plots).
Employ areas of semi-natural habitat for rough grazing (includes salt marsh, lowland heath, bog, fen)

A replicated trial in the UK (Vale & Fraser 2007) found that songbirds and invertebrate-feeding birds were recorded more often on semi-natural rough grazing than on upland improved pasture, but the opposite was true for crows (Corvidae). Bird numbers and species were recorded in plots of improved upland pasture grazed by cattle and sheep (with and without seasonal removal of grazing in summer, 10 replicates for each) and in plots of semi-natural rough grazing grazed by cattle from June to September (six replicates). The proportion of surveys where songbirds and invertebrate feeders were recorded was greater on semi-natural rough grazing than on improved pasture. However, the effect on the number of individuals varied over the year. The number of birds of invertebrate-feeding species was greater on semi-natural grassland between May and July (338 birds, compared to 52 and 41 on improved treatments, with and without seasonal grazing removal), but greater on improved treatments between October and January (5,833 and 1,458 birds on improved treatments compared to 606 birds on semi-natural grassland). There were fewer birds of species in the crow family on semi-natural rough grazing plots at all times of year, but the difference was greatest during July to September (16 birds on rough grazing, compared to 496 and 77 on improved plots). The location of the study was not given.
Reduce grazing intensity

A controlled replicated trial in the UK (Vale & Fraser 2007) found that the response of bird populations to the removal of grazing from upland improved grassland between late May and July varied between functional groups of birds and depended on the time of year. Plots with seasonal removal of grazing had the greatest number of birds of songbird species between May and July (126 birds compared to 60 in control plots), and between July and September (312 birds compared to 169 in control plots), but numbers were similar to those in control plots between October and January (13 and 11, respectively). Between July and September, there were more birds of invertebrate-feeding species on plots with seasonal removal of grazing (105 birds, compared to 41 on control plots), but between October and January there were more birds on continuously grazed plots (5,833 birds, compared to 1,458 on plots with seasonal removal of grazing). At all times of year, crows were more abundant on continuously grazed plots. Bird numbers and species were recorded in plots with and without seasonal removal of grazing for silage making (10 replicates).
Employ grazing in artificial grasslands/pastures

A replicated trial in the UK (Vale & Fraser 2007) found that songbirds and invertebrate-feeding birds were recorded more often on semi-natural rough grazing than on upland improved pasture, but the opposite was true for corvids. This study is discussed in detail in ‘Graze non-grassland habitats’.
Reduce grazing intensity on grassland (including seasonal removal of livestock)

A replicated, controlled trial in 2005-2006 on upland improved grassland in the UK (Vale & Fraser 2007) found that the response of bird populations to seasonal removal of grazing (late May-July) for silage making varied between functional groups and depended on the time of year. Plots with seasonal removal of grazing, had the greatest number of birds of songbird species between May and July (126 birds compared to 60 in continuously grazed control plots), and between July and September (312 birds compared to 169 in control plots), but numbers were similar to those in continuously grazed plots between October and January (13 and 11, respectively). There were more invertebrate-feeding birds between July and September (105 birds, compared to 41 on control plots), but between October and January there were more invertebrate-feeding birds on continuously-grazed control plots (5,833 birds, compared to 1,458 on plots with seasonal removal of grazing). At all times of year, crows (Corvidae) were more abundant on control plots. There were 10 replicates. Bird numbers and species were recorded in plots with and without seasonal removal of grazing for silage making in May-July 2005, July-September 2005 and October 2005-January 2006.