Going through your field guide you will find a number of terms that are often used; these should all be described in the glossary of the guide.
Over the years birders have developed some special terms, for which you will probably not find a description in a book, and understanding them makes birding and a lot of content on this site more understandable.
Ornithologist– person whose job it is to study birds. Professional. Scientist type.
Birder: Anyone who is not an obvious twitcher. Keen but not obsessive, well versed up on identification and general birding stuff, and well acquainted with the local birding sites. Birders often find the rarities for twitchers, and they are always willing to help new birders with their ID’s.
Stringer: Probably the most insulting term in birding, referring to a person that often identifies birds incorrectly and adds them to their life list. This is often the case with rarities reported by such a person, and most other birders will treat any reported sighting with skepticism.
Twitcher : Obsessive list-keeping birder who goes after rare birds found by other people. Twitchers might cross half the country overnight to see one little nondescript bird sitting a kilometer out on a windswept beach. Twitchers all have huge lists that only impress other twitchers. Surprisingly, they are not always good at identifying birds, because they leave all that tedious business to other birders. From twitcher you also get the verb to twitch, to go out with the deliberate intent of seeing one particular rarity you’ve heard about, and you don’t need to be a dedicated twitcher to do this.
BOP: Bird of Prey.
Mega: A very rare bird. Mega’s will see birders from across the country congregate at the spot at a chance of seeing it. Those who are slow off the blocks are often left with an expensive dipper.
To dip (or a dipper): To miss seeing a bird which you were looking for. The joking rule of thumb is that the further you travel for a specific bird, the greater the chance of dipping on it.
Bogey Bird: Having dipped on a bird a few times it can become a bogey bird, especially if every one else is seeing it quite often.
First: A first record of a species (in a defined area, such as a South African first).
Jizz (or Gizz): 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. It generally accepted that the term is slang from the second world war where planes were identified on General Impression Shape and Size (GISS)
LBJ : a Little Brown Job. A large number of birds are small, brown and drab, and they all look almost exactly like at least a number of other species. Female or immature birds are quite likely to be LBJs, and identification can be tricky even for the experts.
Lifer: A first-ever sighting of a bird species by an observer; an addition to one’s life list.
List: a list of all species seen by a particular birder. Most birders keep a life list of the species in their region and possibly a world list, if they are well traveled, and some also keep provincial, garden and other lists. Some birders compete with other birders for having the highest number of species on their list and they are referred to as listers.
String: A dubious record, usually of a rarity which the record cannot be substantiated
Tick: An addition to a list, indicating ticking that species off that particular list
Megatick: an extremely good tick, by virtue of the bird being very rare or very difficult to find. A good tick not just for you, but for any birder, even for most veterans.
Newmans, Sasol, Sinclairs, Roberts: The common names that the four most popular Southern African bird guides are referred to.
IBA: Important Birding Area. Birding locations considered important for the protection of bird life
Blocker: A mega which appears on a regions list, but if you were not one of the lucky ones to see it, you probably never will, thus you are blocked
Vagrant: A vagrant bird is described as a bird that ventures outside of its normal range or migratory route. Most birds do not do this voluntary, but are often blown off course, or make an error in navigation. Most vagrants are migratory, but the odd non-migratory bird also ends up in the wrong place.