Whilst birding Ash Shargiyah Development Company Farm on 11 September 2015 I saw a juvenile harrier over one of the fields. Luckily the bird flew closer and eventually flew right overhead allowing some good photographs to be taken. Juvenile Montagu’s and Pallid Harriers are difficult to identify with certainty at times and good views are needed. The first thing that needs to be done on a bird is to age and sex it. Juveniles are easily aged by being dark above and largely unstreaked chestnut below with dark secondaries and a strong facial pattern.
The main distinguishing characters in order of importance include the primary pattern – Pallid Harrier shows diagnostic unbarred primary bases creating a distinct whitish ‘boomerang’ shape around primary coverts. The fingers are barred and the railing edge is diffuse whereas on Montagu’s the hand normally shows a Buzzard type pattern with unbarred fingers and sharply set-off dark trailing edge, with indistinctly barred bases to central primaries and no pale ‘boomarang’ around the primary coverts.
Facial Pattern – Pallid shows striking facial markings, with diagnostic broad, unspotted whitish collar, emphasised by solid dark brown neck sides (like a ‘boa’), extensive dark ear covert area reaches loral area (occasionally onto throat) and towards the bill base.
The white area around the eye is usually small. Montagu’s Harrier has much more whiter around eye, including deeper supercilium, broader white on cheek and loral region and the dark ear covert patch is smaller; half collar fainter and marked with streaking; dark neck sides made up of streaks and not solid patches and much smaller (i.e. no “boa” effect).
Underpart Streaking – None on Pallid whereas Montagu’s usually shows streaking on breast sides extending down onto upper flanks. From the above it appears this bird is a juvenile Montagu’s Harrier although a well marked individual.