would fly to nearby fields to feed, whilst on other occasions the entire roost would rise into the sky like a black cloud, partake in some form of aerobatics, and then settle into the trees again amidst much noise. Gradually, as the light diminished they would settle down for the night. In Merthyr Tydfil most of the Jackdaws nest in chimneys, old buildings, ruins of former industries, and the like. Because of the industrial nature of the valley such sites are plentiful, and Jackdaws are consequently very numerous. Outside the industrial region the species still uses natural cliff-faces (or darrens'), but old limestone quarries are also favoured. In the cases of these isolated colonies, the birds do not always roost with the rest of Merthyr's Jackdaws but sometimes form small local roosts of their own. REFERENCES BROWNSEY, B. W. and PEAKALL, D. B. (1955). Jackdaw roost continuing throughout breeding season. British Birds, 48, 371. BURNS, P. S. (1957). Rook and Jackdaw roosts around Bishop's Stortford. Bird Study, 4, 62-71. NEW NATIONAL NATURE RESERVES (from the Nature Conservancy) NANT IRFON With the co-operation of the Economic Forestry Group, the Conservancy have acquired about 214 acres of the narrow, steep- sided Irfon Valley as a Nature Reserve. Lying in a remote part of Breconshire, the Reserve's eastern boundary runs along the west bank of the Afon Irfon, which eventually flows into the River Wye. The area is part of a sparsely populated countryside, much of which is over 1,000 ft. above sea-level, near the hamlet of Abergwesyn. Thence the river continues southwards for 41 miles to the village of Llanwrtyd Wells, once famous for its chalybeate and sulphurous springs. The Reserve itself has considerable scenic beauty. At its southern end there is a fairly open uncoppiced wood of Sessile Oak, above which lies a two-mile strip of rugged open moorland with precipitous slopes containing numerous outcrops of Silurian rocks. Pied Flycatchers, Redstarts, Buzzards and Ravens breed in the valley Golden Plover, Curlew, Dunlin and a few Red Grouse occur on the more open parts of the Reserve. These moorland