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Little raven | |
---|---|
Conservation status | |
Least Concern (IUCN 3.1) | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Corvidae |
Genus: | Corvus |
Species: | C. mellori |
Binomial name | |
Corvus mellori Mathews, 1912 | |
Distribution map |
The little raven (Corvus mellori) is a species of the crow and raven family Corvidae, that is endemic to Australia. It has all-black plumage, beak and legs with a white iris, as do the other Corvus members in Australia and some species from the islands to the north.
Taxonomy
Although the little raven was first named by Mathews in 1912, it was only in 1967 that there was consensus to separate it from the Australian raven (C. coronoides) as a distinct species.
Although called a raven, its closest affinities lie with the other four species of Australian corvid, which include the Torresian crow and little crow as well as the forest raven and Australian raven. Initial single gene genetic analysis of the genus using mitochondrial DNA showed the three raven species to belong to one lineage and the two crows to another. The genetic separation between species is small and there was a suggestion the little raven may be nested within the Australian raven, though the authors conceded more genetic work was needed. Subsequent multigene analysis using nuclear DNA by Jønsson and colleagues in 2012 showed the forest and little raven are each other's closest relatives, with the Australian raven an earlier offshoot.
Ian Rowley proposed that the common ancestor of the five species diverged into a tropical crow and temperate raven sometime after entering Australia from the north. The raven diverged into the ancestor of the forest and little ravens in the east and Australian raven in the west. As the climate was cooler and dryer, the aridity of central Australia split them entirely. Furthermore, the eastern diverged into nomadic little ravens as the climate became dryer and, in forested refuges, forest ravens. As the climate eventually became warmer, the western ravens spread eastwards and outcompeted forest ravens on mainland Australia but coexisted with little ravens.
Description
Some of the differences between the two species are as follows: the little raven is, at about 48–50 cm in length on average, somewhat smaller than the Australian raven (though sizes do overlap between both species), the little raven's beak is slightly smaller and more curved, its calls are shorter, and its throat bulges out less while calling. The little raven is a somewhat more sociable species than the Australian raven, often forming large flocks that roam freely over wide areas in search of food. The range of the little raven does overlap the range of the Australian raven, but the latter's range extends further.
Distribution and habitat
The little raven ranges over southeastern Australia from southern South Australia, Victoria and New South Wales. Also in Kangaroo Island (S.A) and King Island (Bass Strait). Living within scrub, agricultural areas, grazing pasture, woodlands to treeless plains, coasts, and suburbs.
Little ravens are absent from west Gippsland, where the land is dominated by forest ravens
Behaviour
Diet
Little ravens eat more insects than C. coronoides and to feed mainly on the ground, but is probably omnivorous to a similar extent to other Corvus species when opportunity arises. Common invertebrates eaten include spiders, millipedes, centipedes (which ravens behead before eating), grasshoppers, cicadas and caterpillars (especially of the family Noctuidae), which are important in feeding nestlings.
Nesting
Little ravens often nest in a loose colony of up to fifteen pairs, with nests few meters apart. They have often been recorded as having several nests within the nesting territory of a single Australian raven which, presumably due to different food preferences, does not seem to consider them a threat to its own food resources.
The nest is a thin cup of sticks with a layer of bark, grass and wool to create a thick mat. Nests are commonly low to the ground (under 10 meters), often in a forked branch in the outer canopy of a tree. Juveniles have brown colored eyes until their 3rd year, their eye color changes to white.
Voice
Its call is a harsh, guttural "kar-kar-kar-kar" or "ark-ark-ark-ark". They also do a quick upward flick of both wings with each note.
External Image Links
References
- Template:IUCN
- Australian Museum Online. "Crows and Ravens". Archived from the original on 1 September 2007. Retrieved 12 August 2007.
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suggested) (help) - Haring, Elisabeth; Däubl, Barbara; Pinsker, Wilhelm; Kryukov, Alexey; Gamauf, Anita (2012). "Genetic divergences and intraspecific variation in corvids of the genus Corvus (Aves: Passeriformes: Corvidae) – a first survey based on museum specimens" (PDF). Journal of Zoological Systematics and Evolutionary Research. 50 (3): 230–46. doi:10.1111/j.1439-0469.2012.00664.x.
- Jønsson, Knud A.; Fabre, Pierre-Henri; Irestedt, Martin (2012). "Brains, tools, innovation and biogeography in crows and ravens". BMC Evolutionary Biology. 12. doi:10.1186/1471-2148-12-72.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - Rowley, Ian (1973). "The Comparative Ecology of Australian Corvids. VI. Why five species?". CSIRO Wildlife Research. 18 (1): 157–69. doi:10.1071/CWR9730157.
- Rowley, Ian; Vestjens, W.J.M. (1973). "The Comparative Ecology of Australian Corvids. V. Food". CSIRO Wildlife Research. 18 (1): 131–55. doi:10.1071/CWR9730131.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)
- The Graham Pizzey & Frank Knight, Field Guide to the Birds of Australia
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