Nature notes
Meet the bird that can walk under water!
The uplands of Britain, with their tumbling, fast-paced, oxygen-rich rivers and streams, thrill even the most hard-nosed mountain types. But usually what makes those same people stand still in their tracks, is the sight of one of this month’s two spotlight species – the grey wagtail and the dipper.
Let’s start with the ‘water wagtail’, as the grey wagtail used to be known, and build up to the crazy world of the dipper. Of the three wagtail species in Britain (pied and yellow being the other two), the grey has the longest tail and the shortest legs, making it easily identifiable as a wagtail. It is memorable in appearance, having a yellow belly and a grey back. The male has a black throat, which along with duller plumage, the female doesn’t have. Many people identify this smileinducing bird as a ‘yellow wagtail’. That’s understandable as the yellow breast is very noticeable, but the yellow wagtail is pretty much all yellow and isn’t associated with water. Look for the grey back and yellow breast to make sure.
Present in much of Britain, they favour upland rivers and streams, and are more of a summer visitor to Scotland. Their ideal habitat is a stream with rocks strewn liberally, allowing them to perch as close to the water as possible. Food is of the insect/bug variety, taken from the stream edges as the current delivers nature’s version of ‘fast food’ right to their door. The most impressive sight is when grey wagtails pluck their food from mid air. It’s called ‘hawking’, and seeing one of these birds flitting up into the evening air chasing backlit mayflies is like watching one of nature’s ballets. The nest is often in a rocky cleft or gap between tree roots.
While the grey wagtail is all elegance and flamboyance, the dipper is one sandwich short of a picnic. And that makes it really interesting. Dumpy and brown, this little bird, at first glance, isn’t much to write home about. But you’ll soon notice that pure white belly or bib. Then you won’t fail to notice the bloody thing won’t keep still. It just keeps dipping up and down. Hold on a minute, I see what whoever named it has done… Both sexes are feathered in an identical fashion. The dipper lays claim to one particular stretch of river all year round, come what may. Even in the chillier months, these hardy birds will plunge into ice-fringed water in search of their favourite delicacy; caddice fly larvae.
Dippers normally let you know they’re around. Just like kingfishers, they call in flight (a buzzing note; the kingfisher, a piping call), just like kingfishers they fly straight and low over water, and guess what? In some parts, dippers were known as ‘King’s Fishers’. That is where the similarity ends. What our short-tailed, white-bellied, bobbing bird lacks in colourful plumage, it makes up for in attitude. Its favourite food (mentioned above), is at the bottom of a fast-flowing river. The dipper can swim. Yes, swim! In fact they can swim before they can fly. They can swim on the surface, with the body low down, or they can swim underwater, using their wings to power them. If that’s not enough, they can even walk along the stream bed, underwater, with a transparent eyelid that they can close enabling them to see. Walking upstream, the short, flattened back deflects the flow upwards, off them, keeping the dipper pinned to the stream bed. I’ve seen this many times in clear upland streams and it never fails to thrill. When it comes to nest sites, rocky clefts by streams are favourites, as are gaps in rocks behind waterfalls, so every time it visits the nest it must fly through the curtain of water.
To those stream-dwelling birds of our mountain world, we salute you and your adaptable ways.
THE DIPPER CAN SWIM. YES, SWIM! IT CAN SWIM ON THE SURFACE, UNDERWATER, AND EVEN WALK ALONG THE STREAM BED