The American green kingfishers are the

kingfisher Kingfishers are a family, the Alcedinidae, of small to medium-sized, brightly colored birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species found in the tropical regions of Africa, Asia, and Oceania, ...

genus ''Chloroceryle'', which are native to tropical Central and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

, with one species extending north to south

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

Species

There are four species: The American green kingfishers breed by streams in forests or

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...

s, nesting in a long horizontal tunnel made in a river bank. They have the typical kingfisher shape, with a short tail and long bill. All are plumaged oily green above, and the underpart colour shows an interesting pattern insofar as the smallest and second largest, American pygmy kingfisher and green-and-rufous kingfisher, have rufous underparts, whereas the largest and second smallest, Amazon kingfisher and green kingfisher, have white underparts with only the males also having a rufous breast band. These birds take

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s and

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

caught by the usual kingfisher technique of a dive from a perch or brief hover, although the American pygmy kingfisher will hawk at

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s in flight.

Evolutionary history

These water kingfishers are descended from a common ancestor which seems to have been closely related to a progenitor of the

pied kingfisher The pied kingfisher (''Ceryle rudis'') is a species of water kingfisher widely distributed across Africa and Asia. Originally described by Carl Linnaeus in 1758, it has five recognised subspecies. Its black and white plumage and crest, as well as ...

(which at that stage had not yet lost the metallic plumage tone), and are similar in plumage and habits (Moyle, 2006). All four have overlapping ranges, and may fish the same waters; however the weight ratio of ''aenea'': ''americana'': ''inda'': ''amazona'' is almost exactly 1:2:4:8, which prevents direct competition for food. The ringed kingfisher, ''Megaceryle torquata'', a more distant relative, also occurs on the same rivers, but is twice as heavy as the Amazon kingfisher. Genetically, the largest species, ''C. amazona'', is the most distantly related, while the medium-sized (but differently colored) ''C. americana'' and ''C. inda'' are sister species. The differing coloration therefore does not indicate their evolutionary history, but rather seems to have evolved independently, to underscore the visual distinctness between taxa, thus helping to keep their gene pools separate (''see also'' Competitive exclusion principle).

References

* * Fry, K & Fry, H. C. (2000): ''Kingfishers, Bee-eaters and Rollers''. * * {{Taxonbar, from=Q860908 *