Quote:
Original posted by lwingkay at 22/09/2008 20:51 
I have been thinking that the yellow wagtail has a green patch of feather on the back while the grey wagtail all grey for the back feather.
This is a closer look at the back feather for the same wagta ...
Your method for separating grey wagtail and yellow wagtail is wrong. In fact, grey wagtail has a yellow/green rump which contrasts with the grey back, whereas on yellow the rump and back are the same colour (green or greyish in HK, depending on time of year and age of the bird). There are a number of differences between the species - habitat, tail length and leg colour are all mentioned. Also call, head pattern, wing bars and undertail coverts (always yellow on Grey Wagtail, but yellow only on breeding plumage Yellow Wagtail)
