White Wagtails – an easy ID shortcut

White Wagtail (Scilly, 21 Oct 2009). Autumn birds like this typically look
smart, having completed their moult before migrating. Photo: Steve Young.

Pied Wagtail (Seaforth, Lancashire, 4 Sep 2003). This rather dishevelled
female is undergoing a longer wing and body moult. Photo: Steve Young.

Although most birders don’t have many problems separating Pied and White Wagtails in spring, the two seem to cause a lot of confusion in autumn, when grey-backed juvenile Pieds confuse the issue. However, there is a very simple fact that gets overlooked in the separation of the two forms in autumn, and which renders the identification of White Wagtails at this time of year very straightforward.

Birds need to be in tip-top condition when they migrate, not only in terms of their fat reserves and general health, but also regarding their plumage. Moult does not take place during migration, as this would put a strain on the bird and would also impact on its aerodynamics, thus reducing its flight efficiency. Although some birds, such as adult waders, may suspend their moult during migration, most migrants complete their post-breeding and post-juvenile moults prior to migration. This means that most migrants are in completely fresh, neat and immaculate plumage when on their autumn migration, and this is particularly true of passerines.

Pied Wagtail is much more sedentary than White Wagtail and, like many essentially resident species, it has a rather protracted autumn moult. To confirm this, Birds of the Western Palearctic (Vol V) states that, in a non-migratory population of Pied Wagtails in southern England, the average duration of primary moult was estimated as 76 days, with an average start of 16 July and an average completion date of 30 September. Body moult more or less covered the same period. However, in migratory White Wagtails in northern Finland, the moult starts on 8 July (on average) but they take only 46-48 days to complete their moult. This means that, by the end of August, these high-latitude White Wagtails will have completed their moult and be ready to migrate south. Unfortunately, there is no data in BWP for Iceland, from where most of our migrant White Wagtails originate (at least those in western Britain). However, it is clear from my own observations in Somerset that White Wagtails in autumn (which usually appear from the first week of September) have already completed their post-breeding or post-juvenile moults, whereas the local Pieds are still in obvious moult well into September.

White Wagtail (Aswan, Egypt, 15 Oct 2005). Moult is completed prior to
migration, so plumage should appear immaculate. Photo: Dominic Mitchell.

Pied Wagtail (Seaforth NR, Lancashire, 12 Sep 2003). In contrast, Pied
takes longer to complete its moult, and appears scruffy. Photo: Steve Young.

The important point to make, therefore, is that in late August and September migrnt White Wagtails are always in newly moulted, ‘clean’, immaculate and fresh winter plumage, whereas local Pieds are still looking scruffy, ‘moth eaten’ and often dishevelled. As far as the young birds are concerned, in late August and September, you are in fact comparing first-winter Whites with Pieds that still retain a significant amount of their weak and fluffy juvenile body plumage. Such birds have black breast patches, whereas first-winter Whites have already acquired a neat and contrasting narrow crescent-shaped necklace across the lower throat/upper breast. In addition, this stands out as it contrasts strongly with the almost completely white underparts. On adult Whites, the necklace is thicker.

Pied Wagtail is a darker, sootier grey on the upperparts (adult males are largely black above), but the important feature of autumn Pied is its extensive dark sooty-grey flanks. White Wagtails have white flanks, with just some restricted pale grey confined to the sides of the breast, around the bend of the wing. The white flanks are readily apparent in flight and this allows even flying birds to be identified with some degree of confidence.

To sum up, autumn White Wagtails look clean, neat and immaculate; they are pale grey above, with white flanks and a neat and contrasting black necklace across the lower throat/upper breast. September Pieds, on the other hand, are rather scruffy and moth eaten, a result of their active moult. They retain significant amounts of black on the breast, they are a dark smoky-grey above and they have extensive smoky-grey breast sides and flanks. To put it simply, if you see a scruffy White Wagtail in autumn, then it probably isn’t one!

I would stress that the above relates to observations in western Britain, which involve migrant Icelandic White Wagtails; I have not studied autumn White Wagtails in eastern Britain.

Another Citrine

Juvenile Citrine Wagtail (at sea near Shetland, 7 August 2011). Note the ear-covert surround and double wing-bars, and compare with the images from Seaforth below. Photo: Julian Bell.

Citrine Wagtail is always a good find in Britain, but discovering one offshore must be a once-in-a-lifetime experience. Julian Bell was at sea on his way back to Peterhead on 7 August after working offshore west of Shetland when this dapper juvenile Citrine wagtail landed on board. It was only present for a short time, but long enough for Julian to capture several close-up images, including this excellent flight shot.

The at-sea location of the Citrine Wagtail, south of Shetland.

Citrine Wagtails: different strokes

By Steve Young

The first of the two Citrine Wagtails (photo: Pete Kinsella)

On the evening of Friday 28 August, Pete Kinsella found an odd-looking wagtail at Crosby Marina, next to Seaforth LWT reserve, Lancashire. Attracted by its Citrine-like call, his excitement increased when he saw the head pattern, but his was tempered by the bird’s thin wing-bars and the slight buff tones to its mantle. He took a few shots, half dismissing it as an aberrant wagtail of some sort, or possibly a hybrid. It was only seen briefly by one birder the next morning, and by Pete again briefly on the Sunday.

That same day, Gavin Thomas, Chris Gregson, Pete and I continued to look for the bird. We had no luck until Gavin went to search a different area, and a few minutes later rang to say he had heard it. We joined him and, sure enough, a wagtail flew past and landed briefly, calling loudly. I picked up my bins and saw two broad wing bars and a perfect Citrine head pattern. But Pete exclaimed: “That’s not my bird – it’s a different one, a juvenile Citrine Wagtail!”

The second Seaforth Citrine, clearly a juvenile (photo: Steve Young).

The ear-covert surround is less well defined on this bird (photo: Steve Young).

Unbelievably, it was a 'real' Citrine, found while looking for the original bird! The latter wagtail was never seen again, but images were circulated and some of the responses lean towards a moulting female or first-year Citrine. Interestingly, the ear-covert surround looks to be more pronounced on that bird than on the second Citrine, which is clearly a juvenile.

Juvenile Citrine typically has bold wing-bars and head pattern (photo: Steve Young).

Compare the above Seaforth juvenile to this YouTube footage of another classic individual, taken by ethering at Marazion Marsh, Cornwall, on 2 September 2009 (check out more of ethering's bird videos here):

And here's a recording of a Citrine Wagtail call - noticeably more shrill and rasping than the classic Yellow Wagtail equivalent (though some flava wagtails from eastern Europe and the Balkans eastwards have a more grating call note):

Tern ID revisited - BTO videos

By Dominic Mitchell

Following Keith Vinicombe's earlier post on the identification of Common and Arctic Terns in spring and summer, the BTO has released a helpful video illustrating some of the key identification criteria for both species. These have the added benefits of movie sequences and sound recordings, and are well worth viewing as a basic refresher:

There's also a second helpful BTO ID video on Britain's other three breeding terns, Roseate, Sandwich and Little:

See the Bird ID section of the BTO website for more identification tutorials.