Heather or ling is not uncommon, and white heather is found at Cademuir, Horsburgh, and Crookston. With the heather the red whortleberry (or Idaean vine) and the blaeberry (or bilberry,—not so common as elsewhere), are found on the heights; while the barberry, green and gold in summer, and green and scarlet in autumn, adorns the high hedges at Peebles, Linton, Rachan, and Yarrow. Cotton grass, called when young, mosscrop, and when older, ling, is found in Ettrick and makes white in summer the heathery tracts at Leadburn; white bent, flying bent, stool bent, are all common on the hills in Yarrow and Ettrick. The bracken on the hill slopes and the curled rock brake are abundant. Hart’s tongue and maidenhair fern are rare. The filmy fern is found in Megget.

The trees that grew in the Ettrick Forest were the birch, the Scots fir, the oak, the mountain ash, the alder, the ash, the elm, the hazel. Those introduced are the sycamore or plane tree, the larch, the spruce, and the silver fir (eighteenth century). The "Fauldshope Oaks," the largest clump of natural-grown oak in Selkirkshire, are small, gnarled, stunted trees, quite unlike the lofty trees for which the Forest was famed. Some years ago 300 acres of the south slope of Bowhill were enclosed to see if the indigenous trees would grow up. With few exceptions all the trees that grew up were natives. The oak, however, did not grow. The lessons that have been drawn from this, the "Howbottom Experiment," are that the old forest of Ettrick was not a stately and uniform growth of timber; and that the valleys were clothed with dense brushwood of hawthorn, birch and sallow, while on the hillsides and above the lower growth grew tall and noble trees of Scots fir, ash and oak.

The excavations at Newstead and the discoveries of remains in peat mosses show that the elk, the red deer, the roe, the wild boar, the fox, the badger, the wolf, and the hare must have been more or less numerous in the area in the period of the Roman Invasion. The horse was then represented by the forest pony (like the Shetland) and the Celtic pony (like that of Exmoor). There were two types of sheep, one with nearly upright, the other with large, curved horns. Goats, apparently less common then than sheep, are still found wild in Megget, and near Hart Fell and Broad Law. The oxen of those times apparently belonged to the small Celtic shorthorn species, dark brown or black in colour with a red band on the back. Remains of the urus or wild ox were found at Lindean Loch in 1852, and at Whitmuir and Kerscleugh in Selkirkshire. But the names of the hills and valleys are adequate proof that the district was once haunted by these wild animals. In Ettrick Forest occur such names as Fawn’s Law, Brock (Badger’s) Hill, Earnsheugh (Eagle’s Cliff), Deer Law, Bear Craig, Wolfhope, Buckscleuch, Swinebrae, Oxcleugh, Hartleap, Hyndhope, Gledcleugh (Hawkcliff).

In 1850 Sir John Hay introduced the fallow-deer to the woods at Eshiels; and the roe-deer found in the woods at Portmore and Dawyck is slowly working its way down to the wooded areas of Ettrick and Selkirk. The hill fox, often larger and greyer than in the lowlands, is still dreaded by the shepherds for their lambs and by the keepers for their pheasants. The brown rat, reported to have been first seen in 1777, spread through Peebles to Newlands by 1792; and by 1845 the black rat had disappeared from Manor. Plagues of voles (the short-tailed field vole) were so common from 1891 to 1893 in the south-west of Scotland including the west of Selkirkshire and Peeblesshire that a Royal Commission was appointed to deal with them; but before its report was ready, the voles were exterminated by the buzzards and owls, the tawny and the short-eared, which had collected in the district in great numbers. The brown hare is common in the fields, and the variable, blue or Alpine hare has spread over the whole area and beyond it since 1846, when it was introduced to the Manor district. The squirrel at one time indigenous in the south, retired to the north on the destruction of the ancient woods and forests. In 1772 the Duchess of Buccleuch introduced it at Dalkeith, whence it has spread all over the Tweed area. It is specially destructive to young fir shoots. The otter, though becoming rarer, is still hunted in the Tweed, Yarrow, and Ettrick.

Peebles and Selkirk have not so many varieties of birds as other counties, for there is no sea-coast, and most of the area stands from 200 to 2000 above sea-level, and is largely moorland. There are, notwithstanding about 100 species resident or migrant within the counties.

The thrush and the blackbird are plentiful. In the hills the ring-ouzel, or hill blackbird, though nowhere resident, takes the place of the merle. The whinchat has markedly increased, mainly in Yarrow and Ettrick, since 1904—5. The blackcap and garden-warbler are found in Ettrick, Yarrow and Tweed ; while the sedge-warbler, the "Scottish nightingale," has been decreasing of late. But the chiff-chaff, the willow-wren, and the redstart are fairly common summer visitors. Of the wagtail family, the grey, the yellow, and the tree pippit are known, the third being numerous in the Ettrick, Yarrow, and Peebles hills, the second rare, having been last seen at Tushielaw in 1889. There has been a decrease of late years in the number of swallows. They used to be plentiful in Manor vale, where the cuckoo, also plentiful, drove them out of their nests. Of the finches the commonest is the chaffinch (Scots "Shilla"); but the linnet (whinlintie), less common since the days of advanced farming, and the goldfinch are not unknown. The cross-bill has been seen at irregular intervals. The two buntings, the yellow-hammer and the red bunting, are common, while the snow bunting is a winter visitor in Ettrick valley, and also at Stobo and West Linton. The raven family breeds among the crags in Manor, Megget, and St Mary’s; the carrion crow in Dawyck Woods; and the hooded or grey crow, locally confounded with the carrion crow, near St Mary’s Loch. The jay has been increasing since 1897, but the magpie and the skylark have decreased in numbers. The night-jar, or goat-milker, wrongly persecuted by the keepers, the great spotted woodpecker, and the kingfisher are not unknown, and a specimen of the hoopoe was killed at Edston near Peebles in 1893.

Of birds of prey the owl is common in the area, the white or barn owl at Newark, Manor and Stobo, the long-eared owl in Ettrick. The tawny owl sometimes makes its nests in the trees in the woods. In the twelfth century high trees were left in Ettrick Forest for breeding places for the falcons. The peregrine falcon still breeds in the Traquair, Manor, and Tweedsmuir districts. A golden eagle was killed at Gameshope in 1833. An immature specimen of the osprey was shot at Cardrona in 1910. The buzzard may be seen every autumn in Peeblesshire. A rough-legged buzzard was shot at the Glen in 1876 and one at Eshiels in 1910. Five years ago the honey-buzzard was seen at Dawyck. The heron is common in the Tweed valley, and heronries were, or still are, to be found at the Haining, Cardrona, Portmore, Tweedsmuir, and St Mary’s.

Geese are frequent in the region of the lochs in Selkirkshire, the commonest being the mallard, the golden eye, the shoveller and the tufted duck, the two latter in increasing numbers of late. The game birds, black grouse and red grouse (muirfowl), the indigenous grouse of Scotland, are common. The pheasant often handreared, is numerous in the valleys of the Tweed. Coveys of partridges are common by the roadside. The "mud-dwellers," the golden plover, the lapwing (peewit or peaseweet), the curlew (whaup) haunt the lonely moors and hills in summer. Others less frequently seen are the common and the green sandpiper, while still more rarely come the greenshanks, the redshanks, the grey phalarope, and the stormy petrel. The common and the herring gull haunt the towns near sewage-tainted streams and garbage heaps. Black-headed gulls have colonies at Whitemoss, Linton, the Haining, Kingside Loch, and several mosses between Selkirk and Melrose.