Curlew Mountains

 

See: Curlew Mountains Geology



Although called the ‘Curlew Mountains’ this upland is really a small range of very low hills.  If the Old Red Sandstone Inlier is taken to be synonymous with the Curlew Mountains, they are 52.5 km long with a maximum width of 3 km and average width of 2 km.  Most hills rise from the surrounding countryside that is at around 100 m above sea level, to their tops at between 230 and 250 m above sea level. There is no obvious highest point however Brislagh at 255 m (at G.749047) that is completely planted with conifers is taken by hill walkers to be the highest ‘summit’.  The hills are broken in two places by the basins of Lough Gara and Lough Key.  Indeed at their eastern end, from Lough Key to around Drumshanbo, there is no distinctive range of hills and near Drumshanbo the River Shannon passes south over the sandstone bedrock.  The true hilly terrain is therefore even more restricted to the area between Lough Key in the east and Bockagh Hill (227 m) 8 km to the west of Lough Gara  this being the last high point.  This would make the Curlew Mountains just 23 km long and their lateral influence perhaps up to 4 km wide.


Having outlined their low stature it is still true to say that these hills form a distinctive landscape feature.  Because they are an inlier of sandstone surrounded by limestone, they do stand out as brown heather-clad blanket bog with sitka spruce plantations above the surrounding bright green limestone grasslands.  Their very straight ridge that runs from north-east to south-west also emphasises this effect.


Most of these hills lie in County Roscommon but the boundary with County Sligo runs through the middle of much of the ridge and tiny parts are in Leitrim near Drumshanbo in the east and Mayo to the west of Ballaghaderreen.


The significance of the Curlew Mountains to the traveller going from Dublin to Sligo is that after crossing the central plain of Ireland, the ‘Curlews’ are the first upland scenery one encounters.  When the main N4 road passes over the summit and into County Sligo, the landscape of Lough Arrow with the Bricklieve Mountains nearby, and the Ox Mountains and Dartry Mountains in the distance, signify one having arrived in the west of Ireland.  Prior to the new road being built, the Curlew Mountains with their twisty old road and sharp bends were seen as a hazard in the winter when roads may also be icy and could even be closed by snowfalls.  The railway line from Dublin to Sligo passes through the low area in the hills to the north of Lough Gara, between Boyle and Ballymote, and offers a similar change in landscape scenery.


A question often asked about the Curlew Mountains is whether Curlews have ever nested or lived there.  In fact William Thompson of Belfast wrote “I am not aware whether the chain of mountains in Sligo, called the Curlews, has reference to the bird or not” (Thompson 1850).  The Irish language name for these hills is ‘An Corrshliabh’ which it would appear translates as ‘corr’ (round) or corragh (rugged) and ‘shliabh’ / ‘slieve’ (mountain) ‘The Round Mountain’ or ‘The rugged mountain’ in Joyce (1996); the first interpretation also being given by the Irish Placenames Commission - so there are no curlews!


To the naturalist these hills have little to offer by way of special ecological habitats but they are less managed than lowland areas and do provide some walks through heather moors with peat cuttings and extensive conifer plantations with peaceful rides.  A notable difference from the Ox Mountains is the paucity of cliffs, rocky outcrops and glacial erratics in the Curlews.  Away from paths the ground tends to be very wet because the drainage is all on the surface and a layer of blanket peat up to 2 m deep has formed on the hill tops.  Peat cutting is fairly frequent where the hills have flat tops and sometimes attempts have been made to machine cut the peat, no doubt helped by the lack of rocky obstacles.


The planting of North American Sitka spruce (Picea sitchensis) and pines would also have benefited from the lack of rocky outcrops.  The flanks of these hills tend to be rough acid pastures that are used for cattle and sheep grazing.  The dilapidated field walls and abandoned farm cottages would indicate that the area was once much more intensively managed but today these places are seen as being marginal for agriculture.



Rocks

The desert sandstones and conglomerates are generally quite uninteresting to the average naturalist once it has been noted that they are of a distinctive red colour and in the case of the conglomerates how they contain lumps of rounded minerals and stones giving them the colloquial names of ‘pudding stone’. One place where the conglomerate can be clearly inspected is on the way to the triangulation point at the top of Mullaghthee (196 m) which lies to the west of Lough Gara.  There are relatively few rock outcrops when compared with the cliffs of the limestone mountains such as the Bricklieves, Knocknarea, Dartry Mountains etc. or with the eastern end of the Ox Mountains where there are often more rock outcrops than vegetated ground.  These Curlew Mountains rocks are also devoid of fossils because living things were absent or sparse in the deserts.



Flora

The sides and tops of the hills are clothed in blanket bog where the natural vegetation is ling heather (Calluna vulgaris) with cross-leaved heath (Erica tetralix) and Sphagnum mosses and Cladonia lichens.  Common cow-wheat (Melampyrum pratense) has been recorded in one place amongst the heather.  In some places bog myrtle (Myrica gale) shrubs thrive and in waterlogged places there is bog asphodel (Narthecium ossifragum) often with round-leaved sundew (Drosera rotundifolia) around the margins of pools of open water.  Where the heather has been removed or over-grazed it is replaced by acid-loving grasses such as wavy-hair grass (Deschampsia flexuosa), purple moor-grass (Molinia caerulea) and mat-grass (Nardus stricta).  The most interesting find dates back to the discovery of ‘abundant quantities’ of stag’s-horn clubmoss (Lycopodium clavatum) “on the Curlew Mountains north of Boyle, on trappean breccias, which are here interstratified with red sandstones” (Foot 1871).  This site appears to have been in County Roscommon and has not been recorded again since its original discovery although it has been looked for.  It would seem that much of the rocky places have been colonized by thick gorse (Ulex europaeus) and perhaps the stag’s-horn clubmoss has been lost.  There is also an old record of a tiny fern called Wilson’s filmy-fern (Hymenophyllum wilsonii) also found in 1871 either on Sroove or Mullaghthee hills to the west of Lower Lough Gara.  A search was made of this area in 2013 without success but it could possibly still be in the area.


Forestry tracks often have species along their verges, some of which are native but very often species are brought in with the limestone rock that is used to make the track.  This can result in species that are associated with limestone living in areas that are by the nature of the country rock acid-loving.  Trackside vegetation has been noted to include some slightly less common species such as wood horsetail, creeping tormentil, knotted pearlwort and early-purple orchid.  Unfortunately, many of the plants recorded from the Curlew Mountains in recent times are alien species that are associated with human disturbance such as Japanese knotweed, giant knotweed, bridewort, cherry laurel, rhododendron and montbretia.



Fauna

There is not a lot to report about the fauna of the Curlew Mountains.  The common and widespread butterflies like green-veined white, orange-tip, common blue, peacock, speckled wood, meadow brown, small heath and ringlet are all recorded.  One specialty has been seen in the past, namely the large heath in 1974, but with all of the conifer planting and more intensive peat cutting I wonder if it is still there.  A moth trap was run at Limnagh in June 2010 by Seamus Feeney and 32 species recorded but none of them were unusual.  If one is walking over the bogs at the tops of the hills in June then the really big, fast flying, Emperor moth, Northern eggar and Fox moth can all be spotted as they go tearing around!  The usual Common heath moth is abundant on the bogs and the Clouded border is common in the conifer plantations.  It is also worth watching the ground as one walks the tracks through the bogs and conifer plantations as the large, green Tiger beetle (Cicindella campestris) can be spotted taking off when you are about 5 to 10 steps from it, then land again further along the path.  Two species of insect that are generally uncommon in the Sligo-Leitrim area, but that have been seen in the Curlew Mountains are the hoverfly Cheilosia chrysocoma with foxy red fur and the Rhinocerus beetle (Sinodendron cylindricum) with a very distinctive horn on the front of its head in the male.


There are very few birds in the Curlew Mountains but apart from the usual Meadow pipits, Hooded crows, Stonechats etc., there are several records of Red crossbills, Grasshopper warblers and occasional records of Hen harrier and Long-eared owl.  I saw a Red grouse there in 1984 but doubt if there are any there today given the widespread planting of conifers leading to fragmentation of the blanket bog habitat.  Mammals include Pine marten that has spread in the region in recent years and a single Red deer that may have been a wanderer.



References

There are very few relevant references because almost nothing has been written about these hills in the natural history literature.


Foot, F.J. (1871)  On the occurrence of Hymenophyllum Wilsoni in the neighbourhood of Boyle; with notice of new stations for some of our rarer plants in the surrounding district.  Proceedings of the Natural History Society of Dublin (for the sessions 1865-1869) 5:16-17.

Discussion of paper 17-20.


Joyce, P.W. (1996)  Irish Local Names Explained.  Roberts, Dublin.


Thompson, W. (1850)  The Natural History of Ireland.  Volume 2 Birds, comprising the orders Rasores and Grallatores.  Reeve, Benham and Reeve, London.