The Jack Snipe (Lymnocryptes minimus) is a small stocky wader. It is the smallest snipe, and the only member of the genus Lymnocryptes. Features such as its sternum make it quite distinct from other snipes or woodcocks.
The common name has been said to come from the Welsh word for a snipe, giach (pronounced with a hard g), but modern dictionaries say it comes from the masculine name Jack. Alfred Newton hypothesized that, "It may be, as in Jackass, an indication of sex, for it is a popular belief that the Jack-Snipe is the male of the common species; or, again, it may refer to the comparatively small size of the bird, as the 'jack' in the game of bowls is the smallest of the balls used, and as fishermen call the smaller Pikes Jacks.
Adults are smaller than Common Snipe and have relatively shorter bill. Length is 18–25 cm (7.1–9.8 in), wingspan is 30–41 cm (12–16 in) and weight is 33–73 g (1.2–2.6 oz). The body is mottled brown on top and pale underneath. They have a dark stripe through the eye. The wings are pointed and narrow, and yellow back stripes are visible in flight. When seen, the distinctive bobbing movement, as if the bird is on springs, has an almost hypnotic quality.
The head pattern of Jack Snipe differs from Common Snipe and other species in the genus Gallinago, in that there is no central crown-stripe; instead, there are two pale lateral crown-stripes, which are separated from the supercilium by an area of dark plumage.
Jack Snipe can be secretive in their non-breeding areas and are difficult to observe, being well camouflaged in their habitat. Consequently, birdwatchers have developed a specialised technique for finding them. This involves walking through its marshy habitat until a bird is disturbed and flies up. Jack Snipe will squat down and not flush from cover until an intruder is quite close. They then quietly fly a short distance before dropping back into vegetation.
They forage in soft mud, probing or picking up food by sight. They mainly eat insects and earthworms, also plant material.
The male performs an aerial display during courtship, during which it makes a distinctive sound like a galloping horse. It is silent in winter. They nest in a well-hidden location on the ground, laying 3–4 eggs.