Friday, 1 May 2009

Purple Herons find themselves too far north

The months of April and May often turn up rare visitors, birds that have overshot on their spring migration and ended up further north than intended. One of the species well-known for such overshooting is the Purple Heron, at least one individual of which has already be seen in East Anglia this spring. The Purple Heron is a locally occurring but widespread species, breeding from northeast France and the Netherlands east across Europe, into Asia and south into Africa. Birds winter to the south of the breeding range and those breeding in Europe cross the Sahara (a desert crossing of some 30 to 60 hours duration) to winter in sub-Saharan Africa. It is because the species is migratory in habits that some individuals end up reaching Britain each year.

Most of the records of Purple Herons in Britain come from East Anglia, Kent and East Sussex, and most involve single birds. However, a party of four Purple Herons, accompanied by a solitary Grey Heron, were seen to arrive at Salthouse from the northeast on 1st June 1998. The birds circled over the village briefly and then departed inland. The species can prove a frustration for the birdwatcher, often only stopping at a site for a single day and also tending to remain elusive during its stay. Your best chance of seeing the bird is either in early morning or close to dusk, as it flies between feeding and roosting areas. When foraging, the heron can be very difficult to see, since it tends to stand motionless, waist deep in water, within dense vegetation (like a stand of reeds). Large reedbeds are a clear draw and this may be why the RSPB reserve at Minsmere seems to do so well when it comes to attracting them (a position on the east coast does not hurt either). In 2007, at least three birds were present in the second half of May, with two individuals seen to display on several occasions. Any hopes of a breeding attempt were dashed, however, by the arrival of bad weather.

The Purple Heron is noticeably smaller than the more familiar Grey Heron and sports rufous brown and grey plumage, mixed with areas of black and white. Since the species is most often seen in flight, when size can be more difficult to determine, there is scope for confusion with Grey Heron. Generally speaking, a Purple Heron in flight appears as a wholly dark bird while the lighter coloured Grey Heron shows contrast between the grey wings and the white body. It is worth casting a careful eye over any herons that you see over the coming weeks, just in case they prove to be something more exotic.

No comments:

Post a Comment