CORACIIFORMES is a morphologically heterogeneous group of colorful birds, with large heads, short necks, short legs, and, mostly, large bills. They comprise the kookaburras and kingfishers, todies, motmots, bee-eaters, and rollers. These birds are widely distributed, occurring on all continents except Antarctica. However, most species are occurring in Asia and Africa. In total, about 145 to 157 species in about 29-40 genera. So far, nine families recognized here, listed below.
(1) ALCEDINIDAE - River kingfishers; about 22 to 24 species in two to four genera: Alcedo and Ceyx (sometimes Ispidina or Myioceyx also recognized); mostly distributed in Africa, Asia, Indonesia, Philippines, Melanesia, New Guinea, and Australia. Two species of Alcedo in the HANZAB region.
(2) HALCYONIDAE – (Tree or wood) kingfishers; 56-61 species in 8-12 genera; distributed in Africa, Asia, Indonesia, Papuasia, Micronesia, Polynesia, and Australia & New Zealand. Eight non-vagrant species in four genera in the HANZAB region.
(3) CERYLIDAE: Water (or belted) kingfishers; nine species in three genera: Chloroceryle, Megaceryle, and Ceryle; distributed in Africa, s. and e. Asia, and New World.
(4) MEROPIDAE: Bee-eaters; 24 to 26 species in three genera: Nyctyornis, Meropogon, Merops; distributed Africa, s. and e. Asia, Indonesia, Melanesia, New Guinea, and Aust. One species, Rainbow Bee-eater Merops ornatus, in HANZAB region.
(5) CORACIIDAE: Rollers; around twelve species in two genera: Coracias & Eurystomus; distributed Africa, s. and e. Asia, Indonesia, Philippines, New Guinea, and Aust. One species, Dollarbird Eurystomus Orientalis, breeds HANZAB region; another species vagrant.
(6) BRACHYPTERACIIDAE: Ground-rollers; about five species in three genera, which are Atelornis, Brachypteracias, Uratelornis, mostly endemic to the African country Madagascar.
(7) LEPTOSOMIDAE: Monotypic Cuckoo-roller Leptosomus discolor, endemic to Comoro.
(8) TODIDAE: Todies; about 5 species in monotypic genera Todus; widely distributed Caribbean islands of Cuba, Hispaniola, Jamaica, and Puerto Rico.
(9) MOMOTIDAE: Motmots; 8 or 9 species in six genera: Aspatha, Baryphthengus, Electron, Eumomota, Hylomanes, and Momotus. These species are widely distributed in Neotropics from Mexico to Argentina.
Taxonomy of this and related groups are somewhat controversial. Monophyly of the Coraciiformes has been variously questioned and supported, and further study required. Maybe polyphyletic (BWP), have been split into as many as six orders. Recent views tend to identify one order, but the treatment of sub-ordinal taxa varies.
Conventionally, all kingfishers have been treated as a single-family, Alcedinidae, with three subfamilies here, these subfamilies elevated to familial level. The division into three families supported by DNA-DNA hybridization and chromosome studies, but this view has been challenged since these three groups are also considered as monophyletic with respect to their nearest relatives within Coraciiformes.
The most closely related groups are Trogoniformes (trogons), Upupiformes (hoopoes), and Bucerotiformes (hornbills). These, too, have also been classified as families within the Coraciiformes. Other distantly allied groups include Galbuliformes (jacamars and puffbirds) and Piciformes (toucans, barbets, honeyguides, and woodpeckers).
Moreover, Coraciiformes are a diverse group, with few anatomical characters that apply to all families. Palate desmognathous. Feet vary; usually have three toes directed forward and a hallux, but inner front toe reduced or missing in some Alcedinidae. The outer toe reversible in Leptosomidae; forward toes often fused or partly fused. Basi pterygoid process absent or rudimentary Hypotarsus complex. Syrinx tracheobronchial.
Plumage bright, mainly iridescent or pigmentary greens and blues. Infrequently different variations in plumage between ages or sexes. Not well represented in HANZAB region; four families recorded, with 12 non-vagrant species in seven genera. Extralimital families not considered further here. The Coraciiformes occur in most habitats of arid to semi-arid zones to tropical rainforests and mangroves.
Kingfishers, rollers, and bee-eaters all require habitats with at least a few trees, from which to hunt. All breed within hollows in branches or trunks of trees, or in tunnels excavated into banks of earth or termitaria (both arboreal and terrestrial).
In HANZAB region, some species (e.g. Laughing Kookaburra Dacelo novaeguineae) may benefit from partial clearance of wooded habitats, though most are adversely affected by the removal of hollow-bearing trees; others (e.g. Azure Kingfisher Alcedo azurea) adversely affected by removal or degradation of vegetation surrounding wetlands.
Generalized predators of arthropods and small vertebrates. Most are sit-and-wait predators; most hunt by sallying. With few exceptions, normally kingfishers do not pursue prey, contrasting bee-eaters, which do. Both kingfishers and bee-eaters regurgitate pellets of indigestible material, such as insect sclerites. In kingfishers, bee-eaters, and rollers, hatching of broods always staggered, with up to the 1-week difference between oldest and youngest nestlings.
Nestlings squabble for food brought by parents, and nestlings soon learn to move toward the entrance of the nest when they perceive the parent entering with food. If two or more nestlings, the eldest (unless replete) typically takes a protuberant position when the food arrives.
However, when the food is scarce, only older nestlings are fed and others starve and die. Just before fledging, to encourage young to leave nest adults may starve them for one to two days. Parents stay near fledglings, calling and bringing food in response to the begging of the young.
Worldwide, 11 species considered threatened. Overall, the major threatening process is the clearance of habitat, though several species are adversely affected by the introduction of predators, particularly the Common Myna Acridotheres tristis. Given the great similarities between Halcyonidae and Alcedinidae in social organization and behavior and most aspects of internal structure.
Read More - The Melodious Baltimore Oriole Song
No comments:
Post a Comment