Female grey heron vs female blue heron. The females of both great blue and grey herons are significantly smaller than the males. A large female great blue heron and a small male grey heron could therefore be similar in size. Apart from the size differences, however, the sexes of each species are similar.

The grey heron (Ardea cinerea) is a long-legged wading bird of the heron family, Ardeidae, native throughout temperate Europe and Asia, and also parts of Africa. It is resident in much of its range, but some populations from the more northern parts migrate southwards in autumn.

Mainly seen as singles or in small groups, standing quietly in or at the edge of water, less often hunting in fields. Plumage mostly gray overall, with paler neck; adult has white crown, black eyebrows, and black shoulder patch. Like other herons and egrets, flies with neck pulled in to form a bulge.

Male and female grey herons look similar but the female has shorter aigrets. Juveniles are greyer without the darker markings on the head and breast. Their legs are dull brown and their bill has a grey upper mandible and yellow lower mandible.