Blackcaps are a small brown warbler with a well-defined cap – black in the male and chestnut in the female. They are not tremendously striking to look at and often keep a low profile in thick scrub and their song starts off as a scratchy series of notes stop to listen and they transition to a series of the most rich and melodious notes that you can imagine.
They are a summer visitor here and our breeding birds spend the winter soaking up the sun in the western Mediterranean so why are we writing about this particular warbler in January – the answer lies in an incredible story of rapid evolution which has taken place in the last 60 years.
Over the last 60 years Blackcaps have been found to be taking advantage of the British tradition of feeding the garden birds and they have been appearing overwinter on bird tables, especially in the Southwest of England, presumably because of the milder winter weather in this region. The obvious conclusion would be that some of breeding Blackcaps have figured out that they could save themselves some effort and dine al a carte on a nice bird table rather than go to the effort of flying all the way to Spain. BUT ringing (fitting birds with an individually-numbered, lightweight, harmless, metal, leg ring) data has shown that in fact these birds have come from central Europe – Germany, France, Spain(!) and elsewhere. Incredibly these birds have changed behaviour and have struck a good thing – further studies have shown that these birds are all genetically linked and that this is an example of rapid evolution in action! Detailed studies of German Blackcaps have shown that birds that take the short hop to the UK, rather than flying to Spain, arrive earlier on their breeding grounds, lay more eggs and rear more young.
So how can we help? The British Trust for Ornithology is researching this fascinating story and to date 750 wintering Blackcaps have been fitted with and individually unique combination of coloured leg rings and 100 have been fitted with geolocators (very lightweight recording devices that log location based on daylight hours and duration which can be analysed if the bird is recaptured and the device retrieved).
Please look out on your bird tables for Blackcaps and if you are lucky enough to see one with colour rings please report your sighting to email@example.com.
Wintering Blackcaps are certainly present in Aldbourne with one caught last winter and another caught this week (the cover photo is this bird!).
Elsewhere in the parish we hope you have been enjoying the crisp, sunny and calm weather to get out and enjoy the incredible downland that we are privileged to have around us. Stonechats, Ravens and Corn Buntings are showing particularly well at the moment and when the sun is shining the birds are starting to sing with Robin, Dunnock, Wren, Song Thrush, Mistle Thrush and Greenfinch all going for it this week in the village.
Listen out also for the distinctive descendo drumming of the Great Spotted Woodpecker which is also a harbinger of spring that has been around the village this week.
We even had a Red Admiral butterfly on a sunny day last week so look out for unseasonal pleasures!