52 Small land birds, such as the seed- and insect-eaters, lay small eggs, often in large clutches. Large birds often lay far fewer eggs. For birds such as eagles, one small clutch a year is all they produce. Some of the museum specimens here have lost their original colour. Well hidden The nightingale’s brown eggs are well concealed in tangled bushes. Tawny owl egg Little owl egg Heavy clutch Tits lay up to 15 eggs. Each clutch weighs up to a third more than the bird itself. Wood warbler egg Marsh warbler egg Slow beginners Some finches do not lay their eggs until early summer when more seeds are available. Summer visitors Most warblers migrate to breed. They time their arrival to coincide with the annual insect population explosion, which provides food for the average family of six nestlings. Highly visible Owl eggs are white with a glossy surface. Their round shape is typical of many eggs laid in holes. Streaks The streaks on the Baltimore oriole’s egg are formed only a few hours before it is laid. The egg’s pattern blends with the nest. Baltimore oriole Less to lay Wood pigeons lay two eggs that together weigh less than a tenth of the parent. Chimney nest The jackdaw lays its eggs in holes – in trees, rocky outcrops, or even chimneys. Abnormal eggs During the process of egg production, things sometimes go wrong. A single egg may have two yolks, or it may be of a different size to a normal egg. The eggs shown here are crow’s eggs. Moorland camouflage Blotches of colour help to hide this grouse egg among the heather. Outsize egg Carrion crow Chaffinch egg Hawfinch egg Coal tit eggBlue tit egg Normal egg Brown or reddish spots