2cy Montagu's Harriers

a really cracking and obvious 2cy male was hunting locusts on the barley fields -- a second bird in what appears to be juvenile plumage had me head scratching at a distance but when I found it closer early one morning it was obviously a Monties but according to DF's tome the yellow iris should mean its a 2cy male rather than a female as I first assumed -- cannot seem to identify the locust species but in one image there are clear small red spots in the insects larger wings