Grazing and moorland birds

Sheep numbers have increased markedly in the uplands in recent decades. Associated with this, heather moorland has decreased in extent and has been partly replaced by grassland. Few studies have quantified the impact of these changes on bird populations.

In a study conducted by the RSPB in collaboration with the Game Conservancy Trust and Scottish Natural Heritage, the abundance of a suite of moorland breeding bird species was measured and related to detailed vegetation assessments across 85 plots in southern Scotland that had been subject to a range of historical grazing regimes. General linear models were used to analyse the effect of non-vegetation factors such as altitude, soils and crow abundance on bird distribution. Then, the effect of grazing-related vegetation variables in explaining residual variation in bird abundance was determined. 

Of the nine species considered in detail, only red grouse and stonechats were associated with vegetation characteristic of low grazing pressure (particularly medium to tall heather cover), although both species preferred heterogeneous habitats to a monoculture of tall heather. Although moorland breeding waders are often thought to have declined due to increases in grazing pressure, we found no evidence to support this hypothesis in southern Scotland. Indeed, the affinity of golden plovers for open vegetation suggests that high grazing pressure may enhance densities of this species. Skylark and wheatear densities were highest on moorland with short vegetation, while whinchats and meadow pipits were most abundant where bracken and grass respectively predominated over heather. These four species are therefore unlikely to have been adversely affected by increased grazing on heather moorland.

The results of this study confirm that few moorland bird species are closely associated with extensive heather cover, and demonstrate that changes to grazing regimes need to be tailored to the existing habitat condition of a site if they are to be beneficial for moorland birds. Widespread losses of hill sheep may be detrimental to some moorland birds of conservation importance.  |

Pearce-Higgins JW and Grant MC (2001) The effects of grazing-related variation in habitat on the distribution of moorland skylarks Alauda arvensis and meadow pipits Anthus pratensis. Aspects of Applied Biology 67: 155163. 

Figure (below) shows a summary of the distribution of nine widespread moorland bird species in southern Scotland according to grazing-related habitat variation.  The lines indicate the range of habitats occupied, and the solid lines indicate preferred habitats.

http://www.rspb.org.uk/science/Processresearch/2001/grazing_and_moorland.asp

Source: Conservation science 2001

Now (2008), there is at least one senior officer of the RSPB who acknowledges that birds like the Ring Ouzel (turdus torquatus) are in serious decline in some areas BECAUSE of the drastic reductions in sheep numbers on some moors due to the so-called 'Environmental Schemes'. 

He explained that they have looked into the situation thoroughly. The decline is not due to anything adverse in their wintering grounds, but due solely to conditions in their breeding grounds: in our case UK moors and heaths. 

I have seen the decline at first hand. For 27 years I farmed at the head of a valley in Cumbria, surrounded on three sides by open moor; two different commons. Eight years ago we, the graziers on one common, were 'bullied' into joining the ESA Scheme with a 30% reduction in sheep numbers. Two years later we, the graziers on the second common, had unbelievably intense and unpleasant pressure applied to us to to join the same scheme; in this case with an enforced 60% reduction in sheep numbers. Furthermore, the cattle which used to be turned out, and which used to eat the coarse grasses, may no longer be so, unless 6.6 sheep are removed per cow. The inevitable result; wall to wall coarse grass and a loss of bird life, coupled with a decline, after the first two years, in the quality of the sheep and a reduction in the future stock-carrying capacity of the land.

The facts presented by The Institute of Applied Biologists show that moors in different regions of the country are different, both climatically and in terms of vegetation.  They demonstrate that the yield, in terms of dry-matter, of the principle mooorland plants is calculable and that therefore the sustainable stocking rate of any moor is also easy to establish. All this is ignored.

The facts that ADAS experimental farms have already proved that these schemes are commercially non-viable without heavy levels of subsidy (tax-payer's money) are ignored.

The facts that the very animals that have been removed, both cattle and sheep, are the ones that produce meat with the MINIMUM input of oil-based fertilisers and potential human foodstuffs, i.e. grain. are ignored.

The fact that the world is running short of food and fuel is ignored.

All in the interests of ticking boxes and achieving Government 'Targets'.                                                             

         ED.

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