These birds have very short legs and never settle voluntarily on the ground, perching instead only on vertical surfaces. Many swifts have long swept-back wings which resemble a crescent or boomerang. Order: ColiiformesFamily: Coliidae  The mousebirds are slender greyish or brown birds with soft, hairlike body feathers and very long thin tails. They are arboreal and scurry through the leaves like rodents in search of berries, fruit and buds. They are acrobatic and can feed upside down. All species have strong claws and reversible outer toes. They also have crests and stubby bills. There are 6 species worldwide and 1 species which occurs in Guinea. Order: TrogoniformesFamily: Trogonidae  The family Trogonidae includes trogons and quetzals. Found in tropical woodlands worldwide, they feed on insects and fruit, and their broad bills and weak legs reflect their diet and arboreal habits. Although their flight is fast, they are reluctant to fly any distance. Trogons have soft, often colourful, feathers with distinctive male and female plumage. There are 33 species worldwide and 2 species which occur in Guinea. Order: CoraciiformesFamily: Alcedinidae  Kingfishers are medium-sized birds with large heads, long, pointed bills, short legs and stubby tails. There are 93 species worldwide and 12 species which occur in Guinea. Order: CoraciiformesFamily: Meropidae  The bee-eaters are a group of near passerine birds in the family Meropidae. Most species are found in Africa but others occur in southern Europe, Madagascar, Australia and New Guinea. They are characterised by richly coloured plumage, slender bodies and usually elongated central tail feathers. All are colourful and have long downturned bills and pointed wings, which give them a swallow-like appearance when seen from afar. There are 11 species which have been recorded in Guinea. Order: CoraciiformesFamily: Coraciidae  Rollers resemble crows in size and build, but are more closely related to the kingfishers and bee-eaters. They share the colourful appearance of those groups with blues and browns predominating. The two inner front toes are connected, but the outer toe is not. There are 12 species worldwide and 5 species which occur in Guinea. Order: BucerotiformesFamily: Upupidae  Hoopoes have black, white and orangey-pink colouring with a large erectile crest on their head.