Editing Indian roller (section)

==Description==
[[File:Pala Pitta.jpg|thumb|Indian roller in flight showing the intense purple-blue and pale blue bands on wings and tail.]]
The Indian roller is a bulky and broad-winged bird with a large head and short neck and legs.<ref name=Cramp1985/><ref name=Fry1992>{{cite book|last1=Fry |first1=C. H. |name-list-style=amp |last2=Fry |first2=K. |last3=Harris |first3=A. |year=1992 |title=Kingfishers, Bee-eaters and Rollers: A Handbook |publisher=Bloomsbury |series=Helm Field Guides |place=London, New York, New Delhi, Sydney |pages=289–291 |isbn=978-0-7136-8028-7}}</ref> It has a body length of {{cvt|30-34|cm|abbr=on}} with a wingspan of {{cvt|65-74|cm}} and weighs {{cvt|166-176|g}}.<ref name=Cramp1985>{{ cite book |editor1-last=Cramp | editor1-first=S. |editor1-link=Stanley Cramp | year=1985 | chapter=''Coracias benghalensis'' Indian roller |title=Handbook of the Birds of Europe the Middle East and North Africa. The Birds of the Western Palearctic |volume=IV: Terns to Woodpeckers | place=Oxford | publisher=Oxford University Press | pages=778–783 | isbn=978-0-19-857507-8}}</ref><ref name=handbook>{{cite book|editor-last1=del Hoyo|editor-first1=J. |editor-last2=Elliott |editor-first2=A. |editor-last3=Sargatal|editor-first3=J. |year=2001|title=Handbook of the Birds of the World, Volume 6: Mousebirds to Hornbills |page=371|publisher=Buteo Books |isbn=978-84-87334-30-6}}</ref> The bare skin around the eyes is dull orange, the legs and feet are yellow-brown. The bill is tinged with brown at the base. The [[Iris (anatomy)|iris]] is grey-brown.<ref name=Cramp1985/> 

===Plumage===
The [[plumage]] on the forehead, chin and [[Lore (anatomy)|lores]] are pinkish buff, the [[Covert_feather#Ear_coverts|ear coverts]] are darker red-brown with pale cream or pinkish streaks, while the throat is a dull wine-red with narrow cream streaks. The crown and nape are a darker dull turquoise. The back and rump are a bright turquoise, and the belly is pale blue. The [[Covert_feather#Tail_coverts|tail coverts]] are dark purple-blue with turquoise tips. The middle two tail feathers are greyish blue-olive with black shafts, while the surrounding tail feathers are an intense purple-blue with a broad pale blue band and greenish tinge towards the tips. The [[flight feather]]s on the wings have the same purple-blue colour of those on the tail, with a similar pale blue band across the most distal five or six primaries. The underwing coverts and {{birdgloss|axillary feathers}} are pale blue, while the [[Covert_feather#Wing_coverts|upperwing coverts]] are a dull green-blue. The primary coverts are pale blue with olive or purple-blue tips, and the lesser coverts are purple-blue along the leading edge of the wing.<ref name=Cramp1985/><ref name=Fry1992/><ref name=handbook/> The colours look dull when the bird is perched but become vibrant in flight.<ref name=Fry1992/> [[Moulting]] commences anywhere from mid-June to mid-August and concludes between November and the beginning of March.<ref name=Cramp1985/>
[[File:IndianRoller.jpg|thumb|Scan of Indian roller feathers: a primary, two outer secondaries and two tail feathers]]
The blue colours of the flight feathers are [[Structural coloration|structural]] and are formed by microstructures in the [[Barb (feather)|barb]]s that produce blue through [[scattering]], which [[C. V. Raman|C.V. Raman]] noted in the 1930s as being more complex than can be explained by the [[Tyndall effect]].<ref>{{cite journal |author=Raman, C. V. |author-link=C. V. Raman |year=1934 |title=The origin of the colours in the plumage of birds |journal=Proceedings of the Indian Academy of Sciences, Section A |volume=1 |pages=1–7 |doi=10.1007/BF03035682 |s2cid=82356751 |url=http://repository.ias.ac.in/50701/1/50701.pdf |access-date=5 May 2021 |archive-date=5 May 2021 |archive-url=https://web.archive.org/web/20210505133005/http://repository.ias.ac.in/50701/1/50701.pdf |url-status=live }}</ref> Studies in 2010 found the feather barbs structured like a channel with [[β-keratin]] rods {{cvt|100|nm}} in diameter with airspaces between them.<ref>{{cite journal |author1=Noh, H. |author2=Liew, S. F.|author3=Saranathan, V. |name-list-style=amp |author4=Prum, R. O. |author5=Mochrie, S. G.|author6=Dufresne, E. R.|author7=Cao, H. |year=2010 |title=Double scattering of light from biophotonic nanostructures with short-range order |journal=Optics Express |volume=18|issue=11|pages=11942–11948 |doi=10.1364/OE.18.011942 |pmid=20589056|doi-access=free|arxiv=0912.3316 |bibcode=2010OExpr..1811942N }}</ref>

Adult males and females are similar in appearance and there are no seasonal changes.<ref name=Cramp1985/> Juvenile birds are duller, paler and browner in colour,<ref name=pcr>{{ cite book |last1=Rasmussen |first1=P. C. |author1-link=Pamela C. Rasmussen | last2=Anderton |first2=J. C. |name-list-style=amp |year=2012 | title=Birds of South Asia. The Ripley Guide |volume=2: Attributes and Status |edition=Second |publisher=Smithsonian National Museum of Natural History and Lynx Edicions |place=Washington D.C. and Barcelona |isbn=978-84-96553-87-3 |page=270}}</ref> with a dull green crown and dull green-blue belly tinged with buff. The bill is brown with a yellowish base rather than black.<ref name=Cramp1985/>

===Voice===
The Indian roller has a [[monosyllable|monosyllabic]] contact call which varies from a short ''chack'' to a longer, harsher ''tschow''. ''Kaarsch'' calls are made during rolling displays, and increase in frequency and volume as the bird flies towards an intruder. When perched side by side, rollers make [[staccato]] chattering. In the nest, young produce a loud, "distressing" sound when calling for food, while young [[fledge|fledgling]]s make a loud "screaming gobble" after eating. Newly independent rollers make cat-like mews while foraging.<ref name=Fry1992/>

===Differences from other species===
At a distance the species can be mistaken for the European roller,<ref name=Cramp1985/> which is a migrant through parts of the Indian roller's range. The European roller has a longer neck and tail in flight, as well as black [[Flight feather#Primaries|primaries]] and an all-blue head.<ref name=Fry1992/> The Indochinese roller is darker, larger and has a purplish brown and unstreaked face and breast,<ref name=pcr/> and blue-green forehead.<ref name=Fry1992/> The underwing coverts are a deeper shade of blue.<ref name=hbk>{{cite book |author1=Ali, S. |author1-link=Salim Ali |author2=Ripley, S. D. |name-list-style=amp |title=Handbook of the Birds of India and Pakistan |edition=Second |publisher=Oxford University Press |volume=4 |year=1983 |chapter= |pages=116–120}}</ref> Its call is higher-pitched and has a more nasal sound.<ref name=pcr/>