White-tailed Iora

Taxobox
name = White-tailed Iora
status = LC | status_system = IUCN3.1
status_ref = [IUCN2006|assessors=BirdLife International|year=2004|id=51429|title=Aegithina nigrolutea|downloaded=12 May 2006 Database entry includes justification for why this species is of least concern]

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image_width = 240px
image_caption = Foraging on a flowering "Butea"
regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Passeriformes
familia = Aegithinidae
genus = "Aegithina"
species = "A. nigrolutea"
binomial = "Aegithina nigrolutea"
binomial_authority = (Marshall, 1876)

The White-tailed Iora or Marshall's Iora ("Aegithina nigrolutea") [Marshall, G. F. L. Capt. 1876. A new Indian Iora. Stray Feathers IV. (1,2 &3) January 1876:410-413] , is a songbird in the genus "Aegithina" found in parts of India and Sri Lanka.

Distribution and identification

The status of the species has been debated and has only recently been given full species status.Wells, D.R., E.C. Dickinson & R.W.R.J. Dekker. (2003) Systematic notes on Asian birds. 34. A preliminary review of the Aegithinidae. Zool. Verh. Leiden 344, 12-ix.2003: 7-15. ISBN 90-73239-88-5. [http://www.repository.naturalis.nl/document/46744 full text] ] Rasmussen, P and J Anderton (2005) Birds of South Asia. The Ripley Guide. Lynx Edicions and Smithsonian Institution.] Earlier suggestions have been that it was a clinal variant of the Common Iora "Aegithina tiphia". [Hall, B.P., 1957. The taxonomic importance of variation in non-breeding plumage in "Aegithina tiphia" and "A. nigrolutea". Ibis 99: 143-156.]

The diagnostic features of the species are the short wing and tail; white edging to tertials converging broadly at the tip, versus tertial tips black to only narrowly white in "tiphia" and a smaller and shorter bill than "tiphia" from any part of India. The vocalizations are also different. The species is best known from northwestern India, however only a few verified specimen records exist from southern India. It is now also known from Sri Lanka.

There are several races [Dickinson, E.C., R.W.R.J. Dekker, S. Eck & S. Somadikarta. Systematic notes on Asian birds. 35. Types of the Aegithinidae. Zool. Verh. Leiden 344, 12.ix.2003: 17-24. ISBN 90-73239-88-5 [http://www.repository.naturalis.nl/document/46745 full text] ] of the Common Iora that may appear similar to this species:
Salim Ali collected a specimen in the Biligirirangan Hills which was commented upon by Hugh Whistler: [Ali, S. (1942) Birds of Mysore. J. Bombay. Nat. Hist. Soc. 43(3):318-341 (p. 323)] quote|One of the Biligirirangan birds, male ,15 September 1934 from Satyamangala (2,000') and evidently by the softness of the skull and the narrow tail feathers an im­mature bird, could not be distinguished from "A. nigrolutea" as the central tail is washed with white. I cannot believe that this is really "nigrolutea" which has not been recorded from nearer than northern Khandesh and Sambalpur. It is evidently an interesting case of individual variation showing how "nigrolutea" had its origin.

Whistler's comments have been subsequently debated and Daniel Marien notes that the southern boundary of the species is not well understood and further notes that the Biligirirangans specimen commented upon by Whistler was identified positively by Biswamoy Biswas as a "nigrolutea".

Adult females of both species are entirely green above (except for a gray and white tail in nigrolutea) and yellow (dull in winter, brighter in spring) below. The juvenal and first-winter plumages in both sexes of both species are similar to their adult female plumages. First-year birds are best recognized by the possession of more pointed and somewhat narrower tail feathers.

Walter Koelz collected two adult specimens of the species at Salem and the distribution range of the species is believed to overlap significantly with that of "A. tiphia".Marien D. 1952. The systematics of "Aegithina nigrolutea" and "Aegithina tiphia" (Aves, Irenidae). American Museum novitates; no. 1589 [http://hdl.handle.net/2246/4066 full text] ]

quote|Subadults (first-winter) and adults of both species undergo an incomplete spring molt in which usually only the body feathers are replaced, but first-year birds do not at that time acquire the full nuptial dress. This incomplete spring molt seldom involves the tail, but occasionally some males of "tiphia" are found to be molting the rectrices, with green quills being replaced by black ones. This condition exists in several subadult males taken in late May and early June in Nepal; it seems unlikely that this represents an early fall molt, the molt in which subadult males normally acquire the black tail of the adult. No black-backed, green-tailed males of "tiphia" have been reported. It is not clear whether birds in first-year plumage breed, or not. The nuptial plumage of both species is acquired by means of an incomplete molt before the breeding season. In males of "nigrolutea" and in some populations of "tiphia", birds in this plumage have a golden yellow chin and throat and a variable amount of black on the dorsum; in Himalayan, Chinese, north Siamese, Indochinese, Javan, Balinese, Bornean, and Palawan forms of "tiphia" the males have a green-backed, feminine type of plumage. Adult males of both species are black-tailed at all seasons, except on Java and Bali where "tiphia" males are always completely henfeathered; in "nigrolutea", at the other extreme, even subadult males have a black and white tail.|Daniel Marien

Habits

The species is believed to have a courtship display not unlike that of the Common Iora. Breeds from June to August and nests low in a bush. Presumed to be resident but little is known.

References

External references

* [http://www.orientalbirdimages.org/search.php?action=searchresult&Bird_ID=2202 Photograps from the Oriental Bird Club collection]