Dictionary.com
definitions

bird-dog

[burd-dawg, -dog]
See more synonyms for bird-dog on Thesaurus.com
verb (used with object), bird-dogged, bird-dog·ging. Informal.
  1. to follow, watch carefully, or investigate.
  2. to seek out.
verb (used without object), bird-dogged, bird-dog·ging.
  1. Informal. to follow or watch carefully.
  2. Slang. to steal or attempt to steal another person's date.

Origin of bird-dog

v. use of bird dog
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for bird-dogging

investigate, pursue, shadow, tail, track, trail, watch