Black-crowned Night Herons

The only reliable way of separating North American (hoactlii) and European Black-crowned Night Herons is on the bare part coloration in full breeding plumage (from mid April through late May). Hoactlii has much duller bare parts. Rather off-pink in colour (often described as ‘salmon-pink’, whilst nominate nycticorax has strikingly reddish legs (and lores) during the courtship period.

he differences in the pale forehead width and supercilium are highly variable between individuals and can not be used as a reliable feature for separation.

At Edinburgh Zoo in Lothian, there was a free-flying breeding colony of BLACK-CROWNED NIGHT HERONS (of the North America hoactli form) from 1951 until 2004, peaking at around 64 birds in 1982. The last known surviving bird from that
colony was a multi-coloured ringed bird still present in June 2007. However, during 2000-2004, a number of young fledged from nests and were not ringed. It is possible that some of these birds still survive in the UK.

I am indebted to Stephen Welch and Ian Andrews for much valuable information and to other North American correspondents who very kindly responded to my information regarding racial identification.

Whilst there is every possibility that the current Lancashire adult may be of the form hoactli (and therefore likely to be a surviving Edinburgh Zoo bird), this cannot be proven at present. This individual does have very pale pink bare part colouration.