Feb 07 2020

Bird of the Month – Dipper

For most of its journey through Fingle Woods, the River Teign flows from west to east at the bottom of a steep-sided valley which rises more then 150m above the water. For several weeks either side of the Winter Solstice the sun barely climbs high enough over the southern slopes for its rays to reach the valley floor. During especially cold weather, hoar frost may linger for days on the trees that line the river and the ground will remain frozen hard. As you descend to river level from one of the higher paths on a day like this you can often feel yourself plunging into a ribbon of cold, damp air that fills the bottom of the valley.

A cold winter day beside the River Teign

These conditions make the lower parts of the valley a harsh environment for the bird species which overwinter at Fingle. On the coldest days many of them will move further up the slopes, where sunlight and higher temperatures make feeding and conserving energy easier.

If you are brave enough to venture out on a frosty morning, and follow the riverside track between Fingle and Clifford Bridge, or from Clifford on through Cod Wood to Ross Meadow, you might be surprised to hear a solitary bird raising its voice in song above the roaring of the fast-moving water.

A closer inspection of the boulders and dead branches poking through the surface of the water will often reveal the source of the song – a small, dark coloured bird with a brilliantly white chest. This is a Dipper (scientific name Cinclus cinclus), and despite its small size it must be one of the toughest birds you can find at Fingle!

        

A Dipper beside the River Teign

Dippers are year-round residents here, and as December brings short days and cold nights to the valley they are already starting to stake out their territories – both to secure a food source throughout the winter months and in preparation for the coming Spring. A territory may cover a kilometre or more of river, and male birds will establish a series of favourite song perches, usually on boulders in the middle of the watercourse but also on low branches along the water’s edge. The bird will sit on these perches, often splashed by near-freezing spray, and sing loudly enough to be heard over the noise of a river in winter spate. The song is a complex series of wheezy notes and trills, often delivered continuously for quite a long period of time (link to a recording of a Dipper at Dunsford Woods by Alexander Henderson). If disturbed, or when moving between perches, the bird will fly low over the surface of the water while uttering a loud “tzip!” call

  A rock splattered with droppings in the middle of the river is a good sign of a Dipper’s hunting or singing perch.

If you watch a Dipper closely as it sits on a song perch, you’ll notice that it frequently bobs up and down on the spot. It’s this habit which gives the bird its name, and the exact reasons for the behaviour are still unknown. The bobbing might make it harder for predators to spot the bird amidst the fast-moving water, it might be a form of territorial display, or perhaps a way of spotting potential prey though the refraction of the water’s surface.

For a bird which lives its whole life along a watercourse, it’s no surprise that a Dipper’s diet mostly comes from the river as well. They feed on aquatic invertebrates, such as mayfly and caddisfly larvae, as well as small fish. They hunt for these by plunging into the fast-moving water, where they use their wings to push themselves down onto the riverbed, half flying and half walking against the strong current. Mayflies and caddisflies are very sensitive to pollution, so this diet makes Dippers dependant on fast-flowing streams and rivers with good water quality, hence why they are most often found in upland areas of the northern and western UK.

Video link https://finglewoods.org.uk/wp-content/uploads/2020/02/Dipper.mp4?_=2

The natural nesting site for Dippers is a crevice in a rocky riverbank, but they are equally at home amongst the stones of a man-made structure such as a bridge or weir. Eggs are usually laid in late March or early April, and the young hatch about two weeks later. They will remain in the nest for another three weeks, being fed by both parents. After fledging, they will remain with their parents for a short time, being taught how to hunt for food. One of the highlights of an early May walk along the river is spotting a whole family, with four or five youngsters following a parent over the boulders and debris beside the water as they learn the skills they’ll need to survive the next harsh winter.

Photos, video and text by Tom Williams

There are usually 3 – 5 dipper territories in Fingle Woods each year, distributed along the river between Fingle Bridge and Ross Meadow. Dippers have also been seen visiting the stream in Halls Cleave. They can been seen at any time of year but are most active from December – May.

If you would like to know more about birds at Fingle, Tom will be writing a monthly blog this year shinning a light on a seasonal species. The results of last year’s Breeding Bird Survey can also be found here – Fingle Breeding Bird Survey Report 2019  

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