_Characteristics and Affinities—Changes of Plumage—Structural Characters—Oyster-catcher—Ringed Plover—Kentish Plover—Golden Plover—Gray Plover—Lapwing—Turnstone—Phalaropes—Gray Phalarope—Red-necked Phalarope—Curlew—Whimbrel—Godwits—Black-tailed Godwit—Bar-tailed Godwit—Redshank—Sanderling—Knot—Curlew Sandpiper—Dunlin—Purple Sandpiper—Other Species._ In the present chapter we commence the study of an entirely different class of birds. The Gulls are for the most part seen flying in the air or swimming upon the sea, but the Plovers and the Sandpipers spend the greater part of their time on the ground. Again, Gulls, when adult, are remarkably showy birds, but the Plovers and allied species are just as inconspicuous. Many of the haunts frequented by Gulls are utterly unsuited to the Plovers and Sandpipers. These principally delight in low sandy coasts, mud-flats, slob-lands, and salt marshes. Rocks and ranges of cliff have no attraction for these little feathered runners of the shore; they obtain their food on the shallow margin of the sea, on the sand and shingle, the mud and the ooze, or at low water among the weed-draped stones. They are emphatically beach birds. Such parts of the coast that have little or no beach uncovered at high water, on which they may rest whilst the tide is turning, or at low water on which they can seek for food, are but little frequented by these Limicoline birds. Consequently we find them much more abundant on the flat eastern coasts of England, and some parts of the southern coasts, with their miles of sand and mud and wide estuaries, than on the much more rock-bound north and west.