Red Grouse Populations on Experimentally Treated and Untreated Irish Bog

Breeding bird populations of Irish peatlands

“…As in the current study, PearceHiggins & Grant (2006) found that Sky Lark and Meadow Pipit had the greatest densities, with 7-43 Sky Larks per km 2 and 102 to 157 Meadow Pipits per km 2 . Watson & O'Hare (1979a, 1979b found densities of Red Grouse in spring on blanket bog in Co. Mayo averaged 5 per km 2 , ranging from 0 to 12 per km 2 , Meadow Pipit ranged from 4 to 20 per km 2 , Sky Lark from 0 to 7 per km 2 and Snipe from 1 to 11 per km 2 .…”

“…Red Grouse is a particularly important species in an Irish context as it is the only bird species that is exclusively found on Irish peatlands. Watson & O'Hare (1973, 1979a studied Red Grouse populations on a blanket bog in Co. Mayo and found that after application of fertilizers to a flat area of peatland, heather coverage increased and this led to an increase in grouse density. Another experiment involved fencing off an area of a heavily grazed hill which led to increased growth of heather and subsequent colonization by grouse (Watson & O'Hare 1973, 1979a.…”

“…Watson & O'Hare (1973, 1979a studied Red Grouse populations on a blanket bog in Co. Mayo and found that after application of fertilizers to a flat area of peatland, heather coverage increased and this led to an increase in grouse density. Another experiment involved fencing off an area of a heavily grazed hill which led to increased growth of heather and subsequent colonization by grouse (Watson & O'Hare 1973, 1979a. In moorland in southern Scotland and northern England, Red Grouse was associated with Heather Calluna vulgaris, although it favoured some heterogeneity in cover (Pearce-Higgins & Grant 2006).…”

“…The results of these studies have found breeding season species richness to be very low on raised bog and blanket bog: Madden (1987a) found 12 species on an area of intact raised bog in Mongan Bog, Co. Offaly, with only four species being proven to have bred; Lack & Lockley (1935) found only three species present in a blanket bog site in Letterfrack, Co. Galway. Other studies have focused on single species in peatland such as Red Grouse (Watson & O'Hare 1973, 1979a, Lance & Mahon 1975, Murray & O'Halloran 2003, Hen Harrier Circus cyaneus (Norriss et al 2002) and Common Redshank Tringa totanus (Nairn et al 2004).…”

Moorland Management: A Study of Exmoor.

“…Even if it were, it is uncertain that the grouse stock could ever be husbanded to the high densities achieved on the grouse moors of Yorkshire and Aberdeenshire. Recent research on marginal grouse habitat in western Ireland (Watson & O'Hare 1979b) suggests that birds reared on small islands of good habitat are lost by emigration to surrounding tracts of second-rate habitat, where they may be rapidly mopped up by predation and starvation. The large area of marginal habitat thus acts as a huge 'sink', siphoning off birds which apparently opt out of competing for territories on the more desirable patches.…”