This is the largest tern, with a wingspan longer than that of the common gull. The beak of the adult is very stout and bright red; most have a dark spot on front of the tip, while the primary feathers are dark in all plumages. The legs are black with a dark head and a face mask.
The common tern is very similar to the Arctic tern. The common tern has a longer beak, legs, head and neck and slightly bigger wings. In summer, the beak is orange-red with a black tip, the underside is a pale grey with little to no contrast to the white cheeks, the tail feathers do not reach beyond the wing tips, the primary feathers are white below and the rear edge of the wing is widely or disjointedly darker. In winter, the forehead and underside are white, the front edge of the wing bend is dark and the beak is entirely black.
The Arctic tern is similar to the common tern but with a smaller body, a shorter beak, head and neck, a longer tail, shorter legs and narrower wings. In the summer, an adult bird’s beak is dark red, the throat, breast and belly are a pale grey and long tail feathers hang over the tips of the rectrices when the bird is standing. The top half of the wings is uniformly light grey, and all flight feathers are whitish.
The Sandwich tern is a large bird with a long and evenly pointed beak. In summer, the top half is light grey, the lower half is white, and the wings have a wide white rear edge. The outer 4–5 primary feathers darken over the summer, forming a greyish-black wedge on the wing tip. The legs and beak are black, the beak tip is yellow. In winter, the forehead and crown are white with only a narrow dark ‘face mask’ remaining.
The common shelduck is a goose-like duck of medium size with a long neck and distinctive plumage. The body is stout, the beak is strong and has a noticeable forehead hump, the legs are quite long. The plumage has extensive white areas, the head is dark green, the beak is red and there is a wide rust-brown stripe across the breast. The shoulder and flight feathers, the tip of the tail and the stripe down the middle of the belly are black. The legs of an adult bird are dull pink, whereas those of a juvenile bird are greyish. The male bird’s beak is bright red with a massive red knob, but the female bird’s beak is often duller red with a little beak knob.
The black grouse is a medium-sized land fowl with a small head and beak. The male bird is black with a purple shine, while the undertail, underwing and wing stripe are white. It has striking red ‘eyebrows’. The lyre-shaped tail is upright during courtship ritual but is narrow and appears long when in flight. Female birds are greyish-brown with dark stripes all over and their tails are also greyish-brown with a slight rust-coloured tint.
In contrast to the common redshank, which has a more slender build, longer legs and a longer, finer beak with a very small downward bend at the tip, the base of the beak is only red on the lower part of the beak. A white eyebrow is clearly visible in winter and juvenile plumage. The white stripe continues at the preen gland area as a narrow white ‘crack’. The male bird is completely black in summer, only the top part is slightly dotted and the legs are also black. The female bird has a lot more white dots on the belly and sides. In winter, both adult birds are light grey on the top side and pure white on the underside, the front of the neck and ‘face’ are dirty white. The juvenile bird’s underside is uniformly streaked, and the edges of the large coverts and tertials are finely streaked. The legs are red.
Similar to the green sandpiper but lighter brown in appearance, with larger spots on the top side, longer legs, a narrow-striped tail and sparse stripes on the chest and sides. A pale brow stripe extends behind the eye and the legs are yellowish-green. In flight, the wings’ pale undersides are visible and the toes extend entirely past the tip of the tail. In the summer, the top part of the adult bird is irregularly marked with little white and cream spots, whereas in the winter, the plumage is greyer and more uniform.
The legs and base of the beak are red, the top side is brownish, the chest is striped, the sides are spotted, there is a bright ring around the eye and short eyebrow stripe. During flight, the wide white trailing edge of the wing and the white oblong-triangular preen gland area are visible. In the summer, adult birds have thick, slightly irregular specks and streaks on both the top and undersides; however, in the winter, the top side and breast area are brownish-grey.