Twitchers' vocabulary is the set of jargon words used by twitchers. Twitchers are committed bird-watchers who travel long distances to see a new species to add a species their "lifelist", "year list" or other lists. Some terms may be specific to regional birding communities, and not all are used due to dialectic and cultural differences.
- Big Day: a birding event in which a birder or team of birders tries to see as many species of birds as possible within a calendar day.
- Big Year: a birding event in which a birder tries to see as many species of birds as possible within a defined area (county, state, ABA area, etc.) within a calendar year; originated with the American Birding Association, and the basis for the movie The Big Year.
- To burn up or flog: to beat around in the undergrowth hoping to flush a bird. A desperate measure and not a kind way to treat an exhausted migrant.
- BVD: "Better View Desired", describing a lifer that was observed well enough to identify, but not enjoy.
- CBC: Christmas Bird Count.
- Chooks: already seen or common birds (used in Australia).
- Crippler: a rare and spectacular bird that shows brilliantly, perhaps an allusion towards its preventing people from moving on.
- Dip (or dip out): to miss seeing a bird which you were looking for.
- Dude: "a bird-watcher who doesn't really know all that much about birds." A novice birdwatcher; slightly pejorative term. Also used to refer to someone who primarily seeks out birds for photography rather than study.
- Empid: any of the flycatchers of the genus Empidonax, infamous among North American birders for being difficult to identify in the field without the aid of vocalizations.
- Fallout: a natural occurrence where migratory birds are forced down by adverse weather in a way that makes them congregate in large numbers; generally associated with meteorological and geographical conditions (exclusively in spring, generally in the United States along the Texas and Florida coasts of the Gulf of Mexico).
- First: a first record of a species (in a defined area, such as a county first).
- Grip (or grip off): to see a bird which another birder missed and to tell them you've seen it.
- Jizz or giss: the overall impression given by the general shape, movement, behaviour, etc., of a species rather than any particular feature. Experienced birders can often identify species, even with only fleeting or distant views, on jizz alone.
- LBJ (or little brown job): drab songbirds that are difficult to differentiate and identify.
- Lifer: a first-ever sighting of a bird species by an observer; an addition to one's life list.
- Noun: a list of all species seen by a particular observer (often qualified, e.g. life list, county list, year list, etc.). Keen twitchers may keep several lists, and some listers compete to amass longer lists than their rivals.
- Verb: to keep or compile a bird list (lister is close in meaning to twitcher).
- Mega or megatick: a very rare bird
- Nemesis (or nemesis bird): a bird that has eluded a birder despite multiple attempts to see it.
- Patagonia Roadside Rest Effect (or Patagonia Picnic Table Effect) (US): the phenomenon that occurs when one bird draws many birders to a remote area, who then find more rarities and other interesting species in that same location. Named after an actual roadside rest area just west of Patagonia, Arizona.
- Patch (or local patch): a birding location or set of birding locations near one's home that a birder visits frequently.
- Pelagic (noun): a boat trip designed for birders to find open-ocean (pelagic) species, such as albatrosses.
- Pish: an emphatic shushing or hissing noise used by North American birders to elicit mobbing behavior; made in imitation of alarm calls of chickadees and titmice.
- Plastic: adjective used to indicate a bird which has escaped from captivity, rather than a genuinely wild bird.
- Sibe: a bird from Siberia (usually applied to rare migrants).
- Siesta time (also the doldrums) (US): the period in mid-afternoon when birds (and therefore birders) are least active. 
- Slash: a term used to describe cryptic species pairs not identifiable to species (on a day list), ie. long-billed dowitcher/short-billed dowitcher, willow flycatcher/alder flycatcher
- SOB: "Spouse of Birder", a non-birder spouse.
- Spark bird: a species that triggers a lifelong obsession with birding.
- Spuh: a term used to describe birds only identifiable to genus level (on a day list) (from "sp.", abbreviated form of species).
- Tick: an addition to a personal list (sometimes qualified as year tick, county tick, etc.). Life tick and lifer are synonymous. a tart's tick is a relatively common species added to one's list later than might be expected.
- Twitch: the act of traveling a long distance to see a rare bird. Synonymous with chase.
- Vagrant: a stray far from normal ecological range.
- Yank: a bird from North America (usually applied to vagrants seen in Europe).
- Zootie (US, uncommon): a locally rare or unusual bird.
Some species have nicknames, for example: "RB Flicker" for red-breasted flycatcher, "Gropper" for grasshopper warbler, "PG Tips" for Pallas's grasshopper warbler; in the US, these are generally reserved for common species ("TV" for turkey vulture or "butterbutt" for yellow-rumped warbler). Twitchers (and birders in general) will also use a mixture of scientific and slang terms for feather tracts and so on.
- Anon. 2008. "The A to Z of birding." Australian Geographic 90: 104-105.
- Saha, Purbita. "The Audubon Dictionary for Birders" http://www.audubon.org/news/the-audubon-dictionary-birders
- Swick, Nate. "The Birder Jargon Dictionary" https://thedrinkingbirdblog.com/the-birder-jargon-dictionary
- Oddie, Bill (1980). Bill Oddie's Little Black Bird Book. Methuen Publishing. ISBN 0-413-49480-2.