Bird plumage is generally how most of us determine the species, age and even sex of a bird, particularly in the spring when they are in their much brighter, and sometimes very colourful, breeding plumage. Plumage is a vital part (but not the only part) of bird identification. How many of us though have really thought about the timing and frequency of plumage change (moulting)?!
I have known since I was a young child that birds have a post juvenile moult and thereafter an annual or bi-annual moult. And thanks to the number of gulls and flamingos in this part of the Algarve I have also come to realise quite a few species of birds will have two, three or even more ‘juvenile’ moults over two to four years before they are in their adult plumage. However that was probably the most I had ever thought about why birds moult or the terminology used to describe the various types of moult. Last week though that all changed when we spotted a Black-tailed Godwit in spring moult. Incredibly early.
Immediately we were wondering was this a one-off, a result of climate change or something else? Thanks to Graham Appleton and his excellent Wader Tales blog and also twitter account, we were able to discover the answer.
“Early spring moult is part of a cunning plan to overtake UK godwits and get to Iceland sooner!“
It seems that some Icelandic Black-tailed Godwits have realised (like us!) that wintering in Portugal is a far better option than south Ireland or east England. The benefits of warmer air temperatures, lower wind speeds and consequently more food far outweigh the downsides of a longer migration. A good winter means these godwits can commence their spring moult much earlier than the godwits who over-wintered closer to the Icelandic breeding grounds. They are also in a much healthier and stronger position for the final leg as not only have they had a better winter, most of them have a stop-over on their spring migration in the Netherlands.
By the way apologies my photographs of the Godwits are not up to my usual standard, I’ve been struggling with bird photography recently. Partly because the waders are a lot warier than usual following the recent changes on our local salt pans. And there lies another tale to be told!