_The Birds_ of Hertfordshire have been carefully observed, and the appearance of rare visitors has been duly recorded. At a lecture delivered at St. Albans in 1902, Mr. Alan F. Crossman, F.L.S., F.Z.S., stated that 212 species had been known to visit the county, and mentioned, _inter alia_, that the kingfisher is more numerous in Hertfordshire than formerly, that the heron nested in the county for the first time in 1901, and that the appearance of the bearded titmouse had been noticed on but three occasions. During the last forty years the following birds, among others, have been noticed as occasional visitants: the storm-petrel (_Procellaria pelagica_), golden oriole (_Oriolus galbula_), whooper-swan (_Cygnus musicus_), snow-bunting (_Plectrophanes nivalis_), greater spotted woodpecker (_Picus major_), black tern (_Hydrochelidon nigra_), great northern diver (_Colymbus glacialis_), herring-gull (_Larus argentatus_), cormorant (_Phalacrocorax carbo_), tufted duck (_Fuligula cristata_), hoopoe (_Upopa epops_), crossbill (_Loxia curvirostra_), sheldrake (_Tadorna cornuta_), Guillemot[d] (_Lornvia troile_), Pallas' sandgrouse (_Syrrhaptes paradoxus_), rock thrush (_Monticola saxatilis_), black redstart (_Ruticilla titys_), Dartford warbler (_Silvia undata_), grasshopper warbler (_Locustella naevia_)[d], waxwing (_Ampelis garrulus_), twite (_Linota flavirostris_), hen harrier (_Circus cyaneus_), buzzard (_Buteo vulgaris_), redshank (_Totanus calidris_), greenshank (_Totanus cunescens_) and the little auk (_Mergulus alle_). The lapwing is thought to be increasing in numbers; the writer frequently observed considerable flocks during his recent rambles in the county. Finches are perhaps as numerous in Hertfordshire as in any other county of equal size; the large flocks of hen chaffinches that haunt the farmyards in winter being quite a notable feature. The goldfinch, it is to be feared, is rapidly becoming scarcer; as are also the jay, the woodcock and other birds much more numerous a few years back. Fieldfares and redwings visit the county in great numbers from the N. during the winter; one morning in the winter of 1886 the writer saw many thousands of fieldfares pass over St. Albans from the direction of Luton. The redwing, being largely insectivorous, is often picked up dead in the fields when the frost is unusually severe and food proportionally difficult to obtain. The presence of many woods and small streams attracts a good proportion of the smaller English migrants; the nightingale and the cuckoo are heard almost throughout the county. Moorhens, coots and dabchicks are abundant; the reed-sparrow is heard only in a few districts. Titmice, great, blue and long-tailed, are well distributed. V. POPULATION