The ground rollers are a small family of non-migratory

Bird migration

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

  near-passerine bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s restricted to Madagascar

Madagascar

The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

.
They are related to the kingfisher

Kingfisher

Kingfishers are a group of small to medium sized brightly coloured birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species being found in the Old World and Australia...

s, bee-eater

Bee-eater

The bee-eaters are a group of near-passerine birds in the family Meropidae. Most species are found in Africa and Asia but others occur in southern Europe, Australia, and New Guinea. They are characterised by richly coloured plumage, slender bodies, and usually elongated central tail feathers...

s and roller

Roller

The rollers are an Old World family, Coraciidae, of near passerine birds. The group gets its name from the aerial acrobatics some of these birds perform during courtship or territorial flights. Rollers resemble crows in size and build, and share the colourful appearance of kingfishers and...

s. They most resemble the latter group, and are sometimes considered a sub-family of the true rollers.

Description

Ground rollers share the generally crow-like

Crow

Crows form the genus Corvus in the family Corvidae. Ranging in size from the relatively small pigeon-size jackdaws to the Common Raven of the Holarctic region and Thick-billed Raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents and several...

 size and build of the true rollers, ranging from 25-49 centimetres in length, and also hunt reptile

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s and large insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s. They are more terrestrial than the Coracidae species, and this is reflected in their longer legs and shorter, more rounded wings.

They lack the highly colourful appearance of the true rollers, and are duller in appearance, with striped or flecked plumage

Plumage

Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...

. They are much more elusive and shy than their relatives, and are normally difficult to find in the Malagasy forests. Often the hooting breeding call is all that betrays their presence.

These birds nest as solitary pairs in holes in the ground which they excavate themselves, unlike the true rollers, which rarely nest in ground holes and even then do not dig their own nests.

Systematics

mtDNA analyses confirmed the systematics of this group but indicated that merging Geobiastes into Brachypteracias, as was usually done since the 1960s, should be reverted at least until a more comprehensive review (e.g. supported by fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s) is possible (Kirchman et al., 2001). There is presently no fossil record of ground rollers; Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 remains from Europe at first tentatively assigned to this family were later recognized as quite distinct (Mayr & Mourer-Chauviré 2000). Presently, there is no indication that ground rollers ever occurred anywhere outside Madagascar (Mayr & Mourer-Chauviré, 2001).

Species

There are five species in four genera in the family Brachypteraciidae:

• Genus Brachypteracias
  • Short-legged Ground Roller, Brachypteracias leptosomus
• Genus Geobiastes
  • Scaly Ground Roller, Geobiastes squamiger
• Genus Uratelornis
  • Long-tailed Ground Roller, Uratelornis chimaera
• Genus Atelornis
  Atelornis
  Atelornis is a genus of birds in the ground-roller family Brachypteraciidae. The genus is endemic to Madagascar.- Species :* Rufous-headed Ground Roller, Atelornis crossleyi* Pitta-like Ground Roller, Atelornis pittoides...
  
  
  • Pitta-like Ground Roller, Atelornis pittoides
  • Rufous-headed Ground Roller, Atelornis crossleyi

External links

• Ground-roller videos on the Internet Bird Collection
• Don Roberson's Bird Families of the World