i8o The Irish Naturalist. 



BIRDS OBSERVED BREEDING ON THE COASTS 



OF SI.IGO AND MAYO. 



BY ROBERT WARREN, 

 (A Report laid before the Royal Irish Academj^ 28th May, 1894). 



The coast line of the County Sligo, and that of the County 

 Ma3'o, as far as Belderig Harbour, is of the Carboniferous 

 formation, and, wherever of sufficient altitude, is eminently 

 adapted for the nesting-places of cliff-breeding birds. 



The sea-face of the cliffs consists of series of horizontal 

 shelves and ledges, caused by the weathering and decay of 

 the softer strata, the harder only remaining, and thus forming 

 the ledges upon which the birds have their nests. But at 

 Belderig Harbour, a " fault" occurs, and from that little cove 

 westwards, the North Mayo coast-line is formed of rock of 

 the metamorphic series, so crushed and jumbled together, that 

 the face of the highest cliffs appear crumbling away ; the 

 falling particles, in many places, forming steep slopes, and 

 where lodging, providing most convenient nesting-places. 



On the long line of coast between Sligo and Killala Bays, 

 there are only two parts sufficiently high for the breeding- 

 haunts of cliff-breeding birds ; the larger one of Aughriss 

 Head, and the lesser one of the Killeenduff cliffs. Aughriss 

 Head, situated about twenty-four miles from Ballina, and 

 fourteen to sixteen from Sligo, is a short promontory jutting 

 out from the coast line, about a mile in width, rising to 150, 

 or 200 feet above the sea, and sloping down inland to the 

 level of the adjacent country. It is composed of Carboniferous 

 limestone, and the whole sea-face of the cliff, from base to 

 summit, is divided into shelves and ledges of various widths, 

 running horizontally along the face, and parallel to each 

 other ; but as the rock dips down towards the land side, the 

 outer edges of the shelves are tilted upwards at a slight angle, 

 thus forming sheltered positions for the nests almost invisible 

 from the outside. 



In such a favourable breeding-haunt it was strange that 

 none of the Great Cormorants were to be seen, but immense 

 numbers of the Green Cormorants were nesting on the cliffs, 

 the nests being scattered all over the face of the cliff in every 

 crack and crevice available, and in some of the more sheltered 



