twitcher · noun1
From twitch + -er. The birdwatching sense first recorded in 1970 and recalled as being in use in 1968; claimed by R.E. Emmett to have arisen in 1950s Britain in reference to birder Howard Medhurst who often arrived at rare‑bird sites shivering after riding pillion on Emmett's motorcycle.
Twitcher · noun2
Etymology from Wiktionary, CC BY-SA 4.0.