From Longman Dictionary of Contemporary Englishspotterspot‧ter /ˈspɒtə $ ˈspɑːtər/ noun [countable] 1 → bird/train etc spotter2 someone whose job is to look for or notice a particular type of thing Football clubs send spotters to look for young talent.weather spotter American English
Examples from the Corpus
spotter• Just the thing for all the serious aircraft enthusiasts, spotters, heavy metal fans and number-crunchers to get hold of.• I suppose we're all train spotters at heart.• Why are so many train spotters called Derek?• Here is the story of one of them, Derek, the most unsuccessful train spotter in the world. 