| Race Sub-species | Sooty Blackish Colour |
| Rachis Central shaft of a feather | Sub-adult Immature moulting into adult plumage |
| Range Geographical area or areas inhabited by a species | Sub-montane Hills below highest mountains |
| Raptors Birds of prey and Vultures, excluding owls | Sub-song Subdued version of normal territorial song |
| Record Published, or otherwise broadcast, occurrence | Sub-species Distinct form that does not have specific status |
| Rectrices Tail feathers | Sub-terminal band Broad band on outer part of feather |
| Remiges The primaries and secondaries combined | Supercilia Plural of supercilium |
| Rictal Around the bill | Supercilium Streak above eye |
| Resident Non-migratory and breeding in same place | Symbiotic Interdependence between different species |
| Riparian Along creeks, streams, rivers and waterways | Tail Streamers Elongated ribbon-like tail feathers |
| Roost Resting or sleeping space | Talons Strong sharp claws used to seize or kill prey |
| Rufescent Inclining to redness | Tank Water reservoir |
| Rufous Reddish brown | Tarsus Lower part of a bird’s legs |
| Rump Lower back | Taxonomy Science of classifying organisms |
| Sal Dominant tree of North Indian forests | Teak Dominant tree of South Indian forests |
| Sallies Short flights and returning to perch as in bee-eaters and flycatchers | Terai Alluvial strech of land south of the Himalayas |
| Salt pans Shallow reservoirs for drying out salt | Terminal band Broad band on tip of feather or tail |
| Savanna Open flat land with grass and scattered bushes | Terrestrial Ground living |
| Sedentary Staying in the same area throughout the year | Tertials Innermost wing coverts, often covering secondaries |
| Scalloped Curved markings on edges of feathers | Totipalmate All four toes connected to a single web |
| Scapulars Feathers along edge of mantle | Trailing edge Rear edge of wing |
| Scrape Shallow depression made by birds to serve as nest | Underparts Under surface of a bird from throat to vent |
| Secondaries Inner wing feathers | Underwing Undersurface of a wing including the linings and flight feathers |
| Sedentary Confined with a particular area | Upperparts Upper surface of a bird including wings, back and tail |
| Shaft Central stem of a feather, often hidden | Upperstorey Canopy of a tree |
| Shank Bare parts of a leg | Vagrant Accidental, irregular |
| Sholas Small forests in SW Indian valleys | Vent Undertail area |
| Shoulder Where the wing meets the body | Ventral Undersurface of body |
| Shorebird Long-legged bird living near water | Vermiculations Wavy (worm-like) markings |
| Skins Bird specimens prepared for scientific studies | Vinaceous Red wine coloured warm pink |
| Skulker Bird that mostly remains within vegetation cover | Vocal mimicry Imitating the sounds of other birds |
| Slaty Dull bluish-grey | Waders Shorebirds. Usually, the smaller, longlegged waterbirds |
| Soar Rising flight on still extending wings using thermals | Washed Suffused with a particular colour |
| Speculum Area of colour on secondary feathers of wings | Wattle Bare skin, often coloured, on part of head |
| Streamers Long extensions to feathers, usually of tail | Web Skin stretched between toes |
| Spangles Distinctive white or shimmering spots in plumage | Wildfowl Ducks and geese |
| Species Groups of birds reproductively isolated from other such groups | Wing-bar visible line of colour at tip on wingcoverts |
| Speculum Shiny, colourful patch on secondary feathers of the wing of some ducks | Wing-coverts Small feathers on wing at base of primaries and secondaries |
| Storey Level of the tree or forest | Wing-span Length from one wing tip to the other when fully extended |
| Spur Sharp horny growth on legs of some birds | Winter plumage Plumage seen during the nonbreeding winter months |
| Straw Pale yellow colour | Zygodactylous Having two toes directed forward and two backwards |
| Streaks ‘Lenghtwise’ lines on breasts or tail | |
| Streamers Long extension of tail feathers | |
| Striated Marked with fine streaks |
