Darker, lacking the warmer tones of Common. The warmest suffusion of buff coloration is on the nape

Brown wash on the underparts confined to the upper breast

Shows a very narrow (less than 5mm) white trailing edge to the secondaries, that just curls round and onto the inner web and tapers away

Shows an obvious white trailing edge of 6mm or greater. Broad white square (inner web) tips. Best seen in flight or stretched wing

Uniformly dark-barred underwing

Has a pale unmarked central area to the underwing

Shows wide broad dark bars at least as wide as the white bars

The dark (black) bars are narrower than the white bars

Strong broadly black barred flanks on a white background, giving it a cold tone lacking in any buff or cream colored hue, makes it difficult to differentiate between axillaries and flanks

There is a contrast between the axillaries (which have more white than black) and the flank barring, which has a brown (not white) background

Has extensive dark almost black upper scapulars with relatively limited internal white markings, Scapular edges are whiter and narrower, especially on the lower scapulars, than Common

Dark tertials with fine narrow transverse bars. The tertials fade to ‘ghostly’ towards the base

Typically has 16 tail feathers

Usually only shows 14 tail feathers.

Prominently barred black and white outer tail feather. Has a narrow outer tail feather, averaging 7.2mm

Not as prominent with reduced, diffuse barring. Wider broader outer tail feather, averaging 12.8mm

Shorter than Common, though hard to tell unless side by side

Narrow dark loral stripe, with a wide bulging white fore supercilium kinking above the ye to a narrow rear supercilium

Median crown-stripe is very narrow

Black bar along greater coverts