Wednesday, 15 July 2009

Harrier Mystery Unravelled


Corn Buntings have had an excellent breeding season in East Hertfordshire. This singing male was superbly photographed by Stuart Read

WEDNESDAY 15 JULY

Blustery SW winds with occasional showers but remaining very warm with temperatures reaching 24 degrees C.

SANDON AREA (EAST HERTS) (1200-1600 hours)

Frustrated at not being able to pin down the Montagu's Harriers ranging widely over the rolling countryside between Baldock and Royston since late May, I decided to put in an extra effort today, in an attempt to locate the nest (particularly as harvesting of the fields is commencing and will take place in earnest over the coming weeks).

As it was, I set myself up in position at Deadman's Hill at midday and waited. A male YELLOW WAGTAIL flew with food to a nearby nest and both family parties of Red-legged and GREY PARTRIDGES were seen but raptor species other than Common Buzzard and Common Kestrel were not to be found.

At around 1430 hours I joined Laurence Drummond at the old 'watchpoint' and within a short while located a 'ringtail' harrier quartering low over the fields. After a few seconds it dropped down into a cornfield and out of view. We waited but it failed to reappear. Some 25 minutes later, it flew up from the same location and flew low above the field towards Rain Hill (it had been 300 yards NE of Bury Barns at approximately TL 305 363). From its actions, it was obvious to me that it did not have a nest there nor was holding territory, and after obtaining permission from Wheat Hill Farm and Bury Barns to investigate further, found that the bird in question was actually a 'ringtail' (probably first-summer) HEN HARRIER and NOT a Montagu's Harrier at all. On close views, the bird was incredibly tardy and heavily worn, with missing tail feathers and heavily abraded primaries and wing-coverts. It was a typically heavy harrier with broad wings, noticeably fingered outer primaries, a broad pale upper wing covert patch, a clearly demarcated white rump and somewhat barred uppertail. Montagu's Harrier is a much more slender species with a longer tail and more pointed wing structure.

So now I had the answer. This is why it had been so difficult to locate 'the pair'. The apparent female Montagu's Harrier was actually a female-type Hen Harrier and the male Montagu's Harrier was presumably an unmated bird (unless of course it had a female elsewhere in the area). An adult male Montagu's Harrier departed North Norfolk early this year so it is vaguely possible it is the same bird.

The female MARSH HARRIER was still in the Sandon area (indicating that that species may have bred in the area) whilst it has been an excellent season for breeding CORN BUNTINGS in the vicinity with at least 18 young birds counted between the Wallington site and Kelshall.

TYTTENHANGER GP (1630-1700 hours)

On my way back, I stopped off at Tyttenhanger, where the extensive sandy spit on the east side of the 'wader pit' was covered in birds -:

OYSTERCATCHER (pair)
DUNLIN (adult in breeding plumage)
RINGED PLOVER (1 adult)
Lapwing (165)
Black-headed Gull (138 including 6 juveniles)
COMMON GULL (1 adult)
Great Crested Grebe (3 adults)

On the Willow Farm Pool, I was very surprised to find a juvenile EGYPTIAN GOOSE accompanying 3 Greylag Geese. The pool also held 21 adult Black-headed Gulls, whilst 6 Sand Martins were overhead.

1 comment:

  1. Real neat stuff!! Truly something that interests me. Mysteries are always fascinating.
    BTW! I have been following this another thing I came across. It’s sort of abstract and interesting. It’s something to do with some Legend
    By the way, good writing style. I'd love to read more on similar topics

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