Here are some terms used by birders:

Twitcher – A hard-core birder who goes to great lengths to see a species and add it to his or her list.

Lifer – A first-time sighting for a birder.

Spark bird – A species that triggers a lifelong passion for birding.

Nemesis bird – A species that constantly eludes a birder.

LBJs (little brown jobs) – A blanket term for drab songbirds that are difficult to distinguish from one another.

Vagrant – A bird straying well outside its regular ecological range.

National Audubon Society