We were having lunch along the River Nene when Karen noticed a commotion in the air just behind us. I quickly got onto the slender, almost gull-like raptor being mobbed by a few crows and the pulse quickened as I realised it was something special. As it struggled to shake off the corvids it managed a bit of soaring flight to gain height and with the wings raised in a shallow V we were certain we were watching a Harrier of some kind and a slim bird like this had to be either a Hen, Montagu’s or Pallid.
Overhead against the sky it was impossible to see much of the plumage detail but this bird had a long slim tail and narrow, pointed wings, kinked at times making it look almost like a tern. I was now sure it was not a Hen Harrier and when it did bank enough to see the white rump (the “ringtail”) it was tiny and very hard to see, unlike the broader white splash on a Hen. Although it was hard to be sure, there didn’t appear to be any colour on the underside so I guess it was an adult female: immature Montagu’s Harriers have rusty-brown, almost orange underparts.
Now in all honesty I couldn’t say it was definitely not a Pallid Harrier as these are incredibly hard to separate from Montagu’s, especially in this plumage. But since Pallids barely occur annually in the whole country and have never been recorded in Cambridgeshire I feel pretty justified in adding Montagu’s Harrier to my PBC list.
I always carry my notebook with me but for once my bag had been emptied and I had to use the back of a fag packet (well being a non-smoker the back of an old business card). This hasty pen sketch is an attempt to capture the tern-like jizz and the relative proportions compared with a Carrion Crow.
Montagu's Harrier (Circus pygargus) with Carrion Crow (Corvus corone)
