OBSERVATIONS ON BIRDS IN MID-WALES. 131 



ception of the "llyns" or tarns upon the hills, are almost 

 entirely wanting. The rivers are swift mountain streams with 

 no margin of reeds or sedge. A rock-bound coast holds out no 

 attraction to wildfowl or wading-birds, and many of those which 

 figure upon the list occur only, so far as this county is concerned, 

 in the estuary of the Dovey. Cardiganshire lies far back in the 

 bay, contrasting in this respect with Pembrokeshire, whose 

 islands and far-stretching headlands naturally intercept many 

 birds as they pass up and down St. George's Channel. Inland 

 the county is everywhere cut off from the rest of Wales by a wide 

 stretch of bleak uplands, except on the north, where the Cader 

 Idris range forms a still higher barrier. The Plynlimmon range 

 and its southern extension, forming the backbone of Wales, might 

 be expected to exclude some of the more delicate Warblers from 

 entering Cardiganshire. This appears to be the case as regards 

 the Lesser Whitethroat ; while some resident birds, as the Nut- 

 hatch, Hawfinch, and Tree Sparrow, only occur very exceptionally 

 on the western side of the mountains. The way in which our 

 summer migrants avoid, as far as possible, crossing exposed and 

 treeless moors is well known ; and, as shown in ' The Birds of 

 Devon,' is exemplified by the case of Dartmoor. Hence it 

 becomes a problem to ascertain in what way the summer migrants 

 reach this county. A few species may come from the south, 

 making a westerly deviation to round the hill-district of North 

 Pembrokeshire. The Wheatear and Swallow, upon their north- 

 ward passage, seem to some extent to follow the coast. But 

 there is no evidence that the bulk of the summer birds enter the 

 county in this way. The Wye valley seems to furnish a possible 

 highway, leading up, by means of its highest tributary, to a 

 narrow col in the Plynlimmon range at a height of 1360 ft. 

 From this point there is a rapid descent at once into Cardigan- 

 shire. If this route were made use of, any given migrant should 

 appear at Aberystwyth very shortly after its arrival on the Upper 

 Wye. On March 29th, 1893, the Redstart was singing at a point 

 six miles above Rhayader, and two days later had arrived in 

 force ; but I did not hear one in Cardiganshire till April 5th, and 

 then not at Aberystwyth, but at Glandovey, in the extreme north 

 of the county. The Willow Wren had reached Rhayader on 

 March 31st, 1894, but I did not hear it at Aberystwyth, only 

 thirty miles away, till April 7th. 



