The Purple-throated Fruitcrow

Oct 31, 2010 Features / Columnists, Interesting Creatures in Guyana

A Purple-throated Fruitcrow

The Purple-throated Fruitcrow (Querula purpurata) is a species of bird in the Cotingidae family, the cotingas. It is the only species of the genus Querula. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela; also in southern Central America in Nicaragua, Costa Rica and Panama. Its natural habitat is subtropical or tropical moist lowland forests.
It is a stout medium sized glossy-black bird. Males have a large purple-red upper throat patch and are similar to the gorget of the hummingbirds, extending to the side of the neck. They are said to have a short wide pointed greyish bill, black eyes, and grey legs.
The true crows are large passerine birds that form the genus Corvus in the family Corvidae. Ranging in size from the relatively small pigeon-sized jackdaws (Eurasian and Daurian) 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 continentsveral offshore and oceanic islands (including Hawaii).
In the United States and Canada, the word “crow” is used to refer to the American Crow. The crow is a year round species. The crow genus makes up a third of the species in the Corvidae family. Other corvids include rooks and jays. Crows appear to have evolved in Asia from the corvid stock, which had evolved in Australia. A group of crows is called a flock.
The genus was originally described by Linnaeus in his 18th century work Systema Naturae. The name is derived from the Latin corvus meaning “raven”. The type species is the Common Raven (Corvus corax); others named in the same work include the Carrion Crow (C. corone), the Hooded Crow (C. cornix), the Rook (C. frugilegus), and the Jackdaw (C. monedula). There is no good systematic approach to the genus at present. Generally, it is assumed that the species from a geographical area are more closely related to each other than to other lineages, but this is not necessarily correct. For example, while the Carrion/Collared/House Crow complex is certainly closely related to each other, the situation is not at all clear regarding the Australian/Melanesian species. Furthermore, as many species are similar in appearance, determining actual range and characteristics can be very difficult, such as in Australia where the five (possibly six) species are almost identical in appearance.
The fossil record of crows is rather dense in Europe, but the relationships among most prehistoric species is not clear. Jackdaw, crow- and raven-sized forms seem to have existed since long ago and crows were regularly hunted by humans up to the Iron Age, documenting the evolution of the modern taxa. American crows are not as well-documented. A surprisingly high number of species have become extinct after human colonization, especially of island groups such as New Zealand, Hawaii and Greenland.
Crows make a wide variety of calls or vocalizations. Whether the crows’ system of communication constitutes a language is a topic of debate and study. Crows have also been observed to respond to calls of other species; this behaviour is presumably learned because it varies regionally.
Crows’ vocalizations are complex and poorly understood. Some of the many vocalizations that crows make are a “Koww”, usually echoed back and forth between birds, a series of “Kowws” in discrete units, counting out numbers, a long caw followed by a series of short caws (usually made when a bird takes off from a perch), an echo-like “eh-aw” sound, and more. These vocalizations vary by species, and within each species vary regionally.
In many species, the pattern and number of the numerical vocalizations have been observed to change in response to events in the surroundings (i.e. arrival or departure of crows). Crows can hear sound frequencies lower than those that humans can hear, which complicates the study of their vocalizations.
Loud, throaty “caw-aw-ah”’s are usually used to indicate hunger or to mark territory. When defending a nest site or food, crows will usually enlarge their crest feathers and hunch their shoulders to increase their size. Softer, gurgling sounds have also been observed as a sort of beckoning call, or a call of affection. These noises are emitted from within the throat of the bird, much like a cat’s purring.

(Source: Wikipedia – The Free Online Encyclopedia)