Tower and Town, February 2023 (view the full edition)Nature NotesI see that in the Tower and Town December 2021 issue I mentioned that a dipper was wintering along the River Kennet in Marlborough. Well, the bird has returned and is regularly seen in the Town Mill area in the last hour of daylight. A displaced feather on its right flank identifies it as the same individual and occasional bursts of song suggest it is probably a male. Dippers are small, chunky, stout, short-tailed, short-winged, strong-legged birds living along fast-flowing upland waterways and slower lowland rivers broken by weirs. They hunt their largely invertebrate prey by diving, swimming (both on and below the surface) and walking on the bottom. The dipper's sober plumage helps it to blend into the riverside background until its penetrating 'zit, zit' calls draw attention to its presence. The dark-brown plumage and white throat and upper breast makes it superficially similar to the ring ouzel (hence the nickname 'water ouzel') but a binocular view reveals the head, nape and gorget* are a rich chestnut brown. 
Dippers have a distinctive whirring flight due to their short wings, and a characteristic bobbing, curtsying motion when perched beside the water, giving rise to the Latin name cinclus, cinclus. Whilst under water, the wings are covered by a thin, silvery film of air, due to small bubbles being trapped on the surface of the plumage, which is dense, with a large preen gland for waterproofing the feathers. Their eyes have well-developed focus muscles that can change the curvature of the lens to enhance underwater vision, and nasal flaps to prevent water entering their nostrils. The dipper is a scarce bird in Wiltshire mostly confined to the By Brook and parts of the Frome. Appearances on the River Kennet are very rare, hitherto confined to one or two winter sightings. I occasionally join the dedicated team of two or three enthusiastic watchers lined up on the bridge at Town Mill, waiting for the bird to appear for a few minutes before going to roost under the bridge. While they wait a grey wagtail occasionally appears, or perhaps a kingfisher. One lady asked me what we were looking at as she passed by with her shopping. "It's a dipper" I said and passed her my binoculars. This was the moment when the bird performed its party trick, disappearing underwater for a good twenty seconds. "Can't see any bird" she muttered, and moved on, convinced we were making it up.
*Gorget, noun. An ornamental collar A part of a wimple covering the throat and shoulders; Robin Nelson |