Identification of Harriers in Singapore

Identifying raptors can be difficult, and harriers especially so. In our latest raptor identification article, we discuss identifying the two main harrier species in Singapore, especially in the most difficult plumage types.

Many species of raptors arrive in Singapore around October to November, the most abundant of which are the Crested Honey Buzzards, Chinese Sparrowhawks and Japanese Sparrowhawks. Among the rarer migrants that arrive in Singapore are the Harriers. Three species of Harriers have been recorded in Singapore – the more regular Pied Harrier and Eastern Marsh Harrier, and the much rarer Hen Harrier (only 3 confirmed records).Pied Harrier Circus melanoleucos and Eastern Marsh Harrier C. spilonotus are grassland specialists, usually showing five ‘fingers’ in flight. Pied Harrier typically arrives from the first week of November onwards, while Eastern Marsh Harrier usually arrives from mid-October onwards. While most sightings are usually limited to raptor-watching sessions, over the years patches of grassland have sometimes yielded wintering birds, such as in Changi (where the airport has now been constructed), and more recently in Tuas South. Rapid urbanisation has caused suitable large areas of grassland habitat to become more and more scarce. It would thus come as no surprise that opportunities to see these raptors wintering on our shores are likely to diminish further in the coming years.Harriers have proven to be a seemingly difficult group of birds for most to identify, and this article hopes to shed some light on some of the features which may be used to distinguish between the two species regularly found here. We will first take a look the male, female and immature plumages of each species, before comparing some of the more easily confused groups of plumages.Distinguishing between Eastern Marsh Harrier and Pied HarrierGissTaking a look at the overall shape and structure of Pied Harrier and Eastern Marsh Harrier, Pied Harrier generally has narrower, more pointed wings and more slender body, compared to the broader, more rounded wings and bulkier body of Eastern Marsh Harrier.Head ShapeTaking a closer look at the shape of the head. Pied Harrier has a more rounded-appearance to the head, with a steeper gradient from the throat to the bill. On the other hand, Eastern Marsh Harrier tends to have a more pointed, elongated-looking head, with the throat having a gentler gradient going up towards the bill. Of course, depending on the posture of the bird’s head, this feature may be difficult to determine at times, but where possible a quick look at the head shape would be a good start to identifying the species you are looking at.Close-up photographs of the faces of Pied Harrier and Eastern Marsh HarrierPied HarrierMaleMale Pied Harriers are unmistakable, covered mostly with contrasting patches of black and white. They have a black head and upperbreast, black outer primaries, and extensive white underparts. From above, they have a black mantle and back, a black band across the median coverts, and a large white patch over the lesser coverts.Male Pied HarrierFemaleFemale Pied Harriers look very different from the males, having a brown head and streaking down to the breast. They have white thighs and vent, as well as extensive dark barring on the primaries and secondaries. From above, white ‘shoulders’ can be seen, contrasting with the brown lesser coverts. Dark barring is seen on the whitish primary coverts and greyish secondaries, and the primaries are dark-tipped. Dark bands are visible on the uppertail with white uppertail coverts.Female Pied HarrierImmatureImmature Pied Harriers are much plainer looking than the adults, having an overall brown plumage. They have a brown head, underparts, and underwing coverts, with barring on the whitish primaries and greyish secondaries. From above, the upperparts are also mostly brown, with white uppertail coverts and pale bands on the uppertail.Immature Pied HarrierEastern Marsh HarrierMaleMale Eastern Marsh Harriers have a dark head (ranging from grey to black), with streaking to the upper breast. The underparts and underwings are mostly white, with the exception of the dark outermost primaries. From above, they have a dark mantle, back, and lesser coverts, and white ‘shoulders’. They also have white uppertail coverts, and an unbarred light grey tail.Male Eastern Marsh HarrierFemaleFemale Eastern Marsh Harriers have an overall brown plumage, with streaking extending from the neck all the way down to the belly. The underwing coverts are light brown, and also often show some level of streaking as well. The primaries are whitish with pale barring, which can be variable at times. From above, the upperparts are also brown, with some white on the uppertail coverts (less than Pied Harrier), and barring on the uppertail (thinner bars than Pied Harrier).Female Eastern Marsh HarrierImmatureLastly, we come to the immature Eastern Marsh Harrier. They have an overall dark brown plumage, with a distinctive whitish face and may have a streaked white band across the breast. The underparts, underwing coverts and secondaries are dark brown, and primaries are whitish and unbarred. From above, the...