Marsh Harrier

When I saw my first Marsh Harriers at Minsmere in the early 70s I felt privileged. They were one of the rarest breeding species in Britain and records in Northamptonshire averaged one per year. Thankfully their numbers have increased, and with the current UK population numbering around four hundred pairs, they have become much more frequent in the county. If I see one locally, or anywhere else for that matter, I still feel privileged as they are magnificent birds and great to watch hunting over European meadows or migrating with other raptors high over the arid mountainous terrain of the middle east. That is one thing which will never change.

Down to earth and local. There are few good images of Marsh Harriers in Northants but yesterday Alan Coles managed to capture some of the second calendar year male which has been hanging around at Summer Leys, on and off, for the past couple of weeks.

Male Marsh Harrier, Summer Leys LNR, 26th October 2015 (Alan Coles)

Male Marsh Harrier, Summer Leys LNR, 27th October 2015 (Alan Coles). Note ‘old’ unmoulted outertail feather.

This young male is still showing much immaturity – particularly on the upperparts, which retain extensive pale yellowish mottling on the mantle and forewing. Some male characteristics are clearly evident, though, with greyish-spotted primary coverts, and largely grey tail.

Male Marsh Harrier, Summer Leys LNR, 27th October 2015 (Alan Coles)

Male Marsh Harrier, Summer Leys LNR, 27th October 2015 (Alan Coles)

It still has a diffuse ‘female-type’ head pattern and largely dark underparts, although the ‘male’ pale greyish secondaries and inner primaries with broad blackish tips are prominent. Males are essentially polymorphic, with some adult males appearing identical to adult females.

Northamptonshire records of Marsh Harrier for the last 25 years showing upward trend. Background image: Eastern x Western Marsh Harrier hybrid, Hong Kong, March 2011 (Charles Lam).

In Northants we have seen an increase in records over the past twenty-five years, with ‘good’ years producing in excess of thirty records, although individuals are mobile and may or may not be present for extended periods, so actual numbers are difficult to determine. Our first wintering bird was in the Nene Valley – predominantly at Stanwick GP – during 2001-2002.