“A mind of moderate capacity which closely pursues one study must infallibly arrive at great proficiency in that study.” ―
Although pretty common in north European shores, Purple Sandpiper remains a mythical species in the Mediterranean. The lack of suitable habitat, partly due to the almost non-existent tides but also to the high human development of the coast makes it an actual rare bird, with less than a record a year. During the last weeks, there has been a lingering individual in Barcelona city beach that has attracted much attention. The sight of the bird foraging on a small patch of algae with such a Mediterranean city in the background and hordes of tourists walking by is truly exotic and many birders have taken profit of these sunny winter days to enjoy the extremely close views the bird is offering. Being that tame, the photos obtained show the details of its plumage and allow a proper assessment of its moult and age.
I had never been able to actually study this species. Some years ago, I could enjoy big flocks of them in Andøya, Lofoten, but the light was too poor, there was too much to see around and the days in late November are too short. This time, however, I could focus on the species and got surprisingly puzzled when trying to age it. Indeed, the bird had been aged as a 1stW when the firsts photos emerged, but the pictures taken the following days (of better quality) showed an extensively uniform wing plumage, with just some patches of striking white fringes. Unless they could undertake a very extensive post-juvenile moult, including most tertials, median and greater coverts, the bird should be an adult showing a tricky pattern just in some feathers.
I finally decided – and have the time- to go to see it. Several birders were around, together with tourists and locals enjoying the good weather and the sight of the city from the beach. The bird seemed to be oblivious to everything, taking a nap next to a tiny algae patch, just within 5m from the people. We had to wait for a while to see its bill, and even then it was just for a few seconds. An hour later, almost in the evening sun, it became more active, probably pushed by the waves sweeping the rock it was roosting on. I could get very close to it without causing any disturbance, indeed it carried on sleeping most of the time.
Although beautiful to take nice photos of the bird, the light was a bit challenging to depict the actual feather patterns. However, the close distances allowed a detailed examination and to be able to play with the exposure in order to compare the results with different camera and light settings.
In this particular photo above, the contrast within wing feathers seems quite obvious, with a rather uniform area in scapulars and lesser coverts and some well-defined white fringing in some other small and median coverts. Tertials reflect the light and are hard to assess, but one could make up a different pattern in the lowest tertial, with a broader and better defined white fringe.
Under a more neutral light though, the wing doesn’t look as contrasted. Tertials now look of the same generations and so do all the lesser and greater coverts. The edges are white but smudged, and tend to be silvery at the base of the feather, especially in the inner web. The scapulars are the only feathers to look nicely black-centred and with pure silvery fringes, revealing the actual restricted post-nuptial moult.
Moreover, there’s another feature that strongly points towards an adult: the very restricted orange in the base of the bill, almost imperceptible if not seen that close. I don’t have any experience about how this feature evolves across the winter in 1stY birds, but I bet a 1stW would still show far more orange. In fact, the obvious 1stW depicted in this photo shows extensive orange in both upper and lower mandibles.
We can obtain more information by analysing the length of the bill. According to some references, Purple sandpiper is one of the wader species that shows a higher sexual dimorphism in bill length. The problem, however, is the existence of short-billed and long-billed populations and the overlap between the females of the short-billed and the males of the long-billed. The extremes seem to be safe though and in my unexperienced opinion this bird could well be a male. The bill is shorter than the head and almost completely straight, with just a subtle downwards bend at the very end. Since it’s the most abundant and proven to winter as close as North France, the most-likely origin is Russia, a rather long-billed population. Female Russian Purple Sandpipers should look like this bird at the Black Sea coast, very different to the bird in Barcelona.
All in all, it was a much enjoyable bird and worth-spending some time studying. Thank you very much to the discoverers and to all who have kept track of its daily movements. Good start of the year!
[Update 17th of January] After reading the post, Marc Illa also commented on the age of the bird, and adult too in his opinion. He had seen some birds of known age (ringed) last year in Helgoland, Germany and sent me some photos of them so I could include one here.
Again, some patches of sharply-edged feathers are visible, especially in the lesser and median coverts. One of the tertials is also very striking in that respect, what might constitute just a difference in pattern, not related to the age of the feather. The orange on the bill is more extensive than in the bird in Barcelona but still within adult’s variation.