Although you are reading this article in October, I am writing it several weeks in advance of publication, so for me it is now the end of August. I suppose I should be thinking of autumnal topics, but I find it easier to write about things that are occurring around me at the time, so apologies for being a bit out of date, but I am currently reflecting on the end of the breeding season and the commencement of summer and autumn migration.
The earliest returning migrants are generally wading birds that mysteriously disappeared from Murcia in May and June to breed in the Arctic tundra and which start to trickle back any time from June – July. As they spend very little time in the Arctic it means that they hurry to raise a family before leaving again on their long return journeys to Europe and beyond. The earliest leave in late June and the others, in July and August. We are lucky that some re-fuel here on their long journeys and I love seeing these early returning birds. It is a great opportunity to catch them before they moult and are still in full or partial summer plumage. It is certainly a lot easier for me than going to the Arctic to see them!
The difference in the summer and winter plumage of some species is striking. The breeding season, when they are away from us, is the time when many are in their most colourful finery, showing off in order to find and impress a mate. However, afterwards they quickly moult and change into their dullest, drab camouflage gear to reduce the risk of being caught and eaten by passing predators (particularly avian ones like Peregrine falcons). This is a smart survival strategy, but it doesn’t make life any easier for birders trying to identify which species are being seen in the distance, especially on a dull winter’s day.
I was recently at the Salinas of San Pedro de Pinatar and photographed a couple of Black-Tailed Godwits. The result illustrates the difference in summer and winter plumage particularly well. The bird on the left is in full breeding plumage (or nearly full) which contrasts sharply with the bird to its right that has already moulted into winter plumage. To the uninitiated it would appear that they are entirely different species, but that isn’t the case.
There are two species of Godwit that can be seen at the Salinas outside the breeding season; Black-Tailed and Bar-Tailed Godwit. They are very similar-looking large wading birds that can easily be distinguished if you see them flying; one has a very obvious black tail, white rump and white in the wings, whilst the other has a barred tail, a white wedge shape on its back and the wings are a fairly uniform brown colour. I’ll leave you to work out which is which! However, as they are more often seen wading, identification becomes a bit more difficult because they are a similar size with long beaks, but there are subtle differences. I have included a photo of a Bar-Tailed Godwit in winter plumage and if you look carefully it has a slightly shorter beak that is slightly upturned. Also, its plumage on the back and wings is more streaked in comparison with the plain back and wings of the Black-Tailed Godwit. (Evidently, the name Godwit comes from the 15th century and it is supposed to be an imitation of its call).
Returning to the theme of summer and winter plumage, there are several species of waders that exhibit this striking difference. One of our commonest small waders, nearly always present at the Salinas outside of the breeding season, is the Dunlin (Correlimos Común).
It is very attractive in its summer best, with rufous coloured wings and head, black and white streaking to the throat and a very large black rectangular chest patch. As you can see from the photograph (showing nearly full summer plumage) it can be easily identified. However, when you see the photo of it in winter plumage it is a different kettle of fish. It is a dull brown with very few distinguishing features.
Another over-wintering wader of the Salinas that shows this trait of differing plumages, is the Spotted Redshank. As you can see from the photo of it in summer plumage it is a largish wader with its very dark, striking and almost black plumage, black legs and white spots.
There really isn’t any other similar species here that you could confuse it with, so its identification is easy. However, once it moults into winter plumage identification becomes significantly more difficult as it is then just another dull, drab looking wader that blends in more easily with its surroundings.
I suspect you have had enough of waders by now, so I will move on from waders and talk about other birds associated with water; the colourful and photogenic Black-Necked Grebe and the even more colourful Kingfisher.
Thankfully, Black-Necked Grebes breed here, so you can see them in their beautiful breeding plumage without leaving the region. One of the best places is at the lagoons of Campotéjar where the photo of the Grebe in breeding plumage was taken. However, out of the breeding season the population increases tremendously, with many birds over-wintering in the area around the Mar Menor and especially at San Pedro de Pinatar where many hundreds of birds can be observed on the Salinas. If you now look at the photo of the same species in winter plumage, the difference is quite dramatic; clearly another species with startlingly different summer and winter plumage.
Unlike those that I have mentioned previously, Kingfishers retain their brilliant and beautiful blue and orange colours all year round. As a breeding bird it requires still or gently flowing freshwater that has an abundance of small fish and as you can probably imagine, this type of habitat is rather scarce in Murcia. Therefore, the Kingfisher is only found in a few inland places during the breeding season, but from the end of summer our small resident population is augmented by winter visitors and passage migrants from Northern Europe and other parts of the Iberian Peninsula. At this time of the year it is therefore far more abundant and not so fussy about the habitat, so keep an eye out for a flash of electric blue flying low over the water. It could well be a Kingfisher.
Why do birds have such bright plumage in summer and sometimes all year round?
Well, they certainly don’t do it for our pleasure and delight, but for specific reasons which we don’t always understand. Firstly, it is to attract a mate and intimidate the competition, as the condition of their plumage indicates if they are strong and healthy. Secondly, their plumage is designed to protect them from predators by providing a form of camouflage.
However, the colours we see aren’t always what birds see. Colours are either the result of pigments, or the way the light reflects off feathers, or both. For example, light reflecting off brown feathers can make some birds appear blue (I know it’s hard to believe). More importantly, birds see colours that we do not as they have 4 types of colour receptors whereas we have only 3. This means that they see subtle differences between similar shades of colour and have the ability to see UV light. This makes a huge difference to what they see and what we see. I wonder if the bright all-year-round plumage of the Kingfisher has some camouflage effect or if there is another reason. I’m not sure, but if anybody does know the answer, I would be delighted to hear.
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