"Motacilla raii, the Yellow Wagtails, are generally black and white, grey and white, grey with a yellow…
A (Motacilla alba) or White Wagtail (upper) and a (Motacilla flava) Yellow Wagtail (lower) sitting on…
"The Yellow Wagtail or Motilla flava has characters of the Motacilla alva; tail shorter, not exceeding…