Dipper courtship

 I watched this pair of dippers courting along a stretch of the river Wear near Wolsingham in Weardale earlier this week. It's very difficult to tell the sexes apart but I'm pretty sure that's the male on the right, with his body stretched upwards. The female is fanning her tail and fluttering her wings. There's some brief wing fluttering going on in the second picture too. 

The distinctive white eyelid of  the bird that is blinking shows nicely.

Apart from this posturing, courtship seemed to mainly consist of the male pursuing the female up and down the river. Dippers always nest here, under an overhanging rock on the riverbank, and have a well-defined territory; rival pairs tend to confront each other at territorial boundaries early in the season, and usually turn back when they reach a rival's territory. They also sing with notes that are pitched at a level where they can be heard above the tumult of the river.

Stained Glass Dipper

It's not often that you see native British birds portrayed in church stained glass windows, but you can find this delightful dipper in the window of St.Michael and All Saint's church at Hubberholme in Langstrothdale, in the Yorkshire Dales National Park. The dipper is one of the characteristic birds of fast-flowing streams in the dale. I found these old photos, that I took 25 years ago, when I was clearing out a drawer. 

Must go back to Hubberholme for another look - and to take some better photos. 

The church's other claims to fame are a fine rood screen and the ashes of novelist J.B. Priestley which are buried there.

Well worth a visit if you are in the area.

Teesdale in early June.........

In early June the meadows in the middle part of the dale, around Middleton-in-Teesdale, are full of buttercups, while...

... the hawthorn blossom beside the riverbank footpaths is just past its peak.

In the middle of the river this fledgling dipper has been parked on a stone by its parents that are away collecting food, though it looks like it could feed itself.

This young rabbit was using a coltsfoot leaf for cover but ....

... it would have done better to run for the dense stand of butterbur leaves that could hide a hundred rabbits.

Upstream of Middleton-in-Teesdale, on the way to Bowlees, there are globe flowers blooming on the riverbank, alongside the white umbels of pignut.

You can hear a spotted flycatcher's beak snap shut when it catches a fly ..... and there are plenty of those around, including .....

... dungflies that are plentiful wherever there is livestock grazing in the fields and ....

..... empid flies that use nectaries of wood crane'sbill flowers are fuel stations.

The wet weather hasn't been kind to bees and this little solitary bees resting on an oak leaf looked bedraggled. Can anyone help with an ID? 

Hay rattle is coming into bloom in the hay meadows .....

..... and mountain pansy Viola lutea is flowering well. The epithet lutea means yellow but pure yellow pansies are in the minority - most have variable amounts of purple in their petals and this has a hint of it in the petal tips.

River Wear, Wolsingham

Today's Guardian Country Diary describes a walk along the River Wear at Wolsingham in Weardale. Even though the riverbank woods look bare at this time of year there's always plenty to see along this stretch of river .....

 ... like the exquisite filigree of cypress-leaved feather moss Thuidium tamariscinum. Many woodland mosses make a lot of fresh new growth during mild spells in winter, when more light can reach them through the leafless branches.

There are often some fine fungi along here too on all the decaying wood - like these velvet shanks.

When we had prolonged heavy rain in Weardale a couple of weeks ago and the river rose very rapidly and flooded its banks. It scoured away all the dead leaves but the dead sweet cicely flower stems - which are chest-high here in summer and smell of aniseed - remained rooted but were flattened by the water, leaving a contour map on he ground of the path of the current as it had swept around the tree trunks.

Above the high water mark of the flood there was still a thick layer of autumn's decaying leaves ...

...... with bluebell leaves already spearing through.

Closer to the river the retreating water had deposited a thick layer of silt, but the buried snowdrops that grow in profusion here early in the year had already forced there way up to the sunlight and started to bloom.

When the water level falls if leaves behind these dark, temporary pools amongst the alders on the edge of the river. Sometimes there are fish trapped and the local herons are well aware of this - there are always heron footprints around the edges. In the spring toads breed in the pools and then it's a race against time for the tadpoles to develop before the pools dry up.

This stretch of river always has resident dippers and at this time of year they sing a lot, establishing their territory. It's amazing how you can always hear their song above the sound of the river - its pitch must have evolved to penetrate the background noise of the water rushing over a stony riverbed.

The riverside woodlands are constantly raided by parties of long-tailed tits .....

nuthatches ......

..... and treecreepers, all looking for insects in tree bark crevices, while ........

...... this heron, evidently out of luck in the riverside pools, flapped away to try its luck on earthworms in the fields above the river.

Dipper

Photographing dippers can be a frustrating business - they have a habit of waiting until you get within range then flying off around a bend in the river, a sequence that's repeated until they get to the limit of their territory, when they turn around and fly back downstream. This one, on the River Derwent near Blanchland in Northumberland, was more accommodating because, I suspect, it's one of this year's juveniles. It's remarkable how well its plumage blends with the peaty-brown colour of the water - take your eye off one of these delightful birds for a moment and it can be a struggle to locate it again.

In this picture it's plunging into the current to feed. Dippers can swim like ducks but also walk under water, held down by the pressure of the current on their back, searching amongst the stones for food items. It's interesting how it seems to close its eyes when it pushes its head into the water - much as we might when we dive into a swimming pool. I assume they must open them again once they're submerged...

This is the moment when it became aware of my presence - and whizzed off around the bend in the river...

Tales from the Riverbank....

Many of the rocks along the banks of the upper reaches of the river Wear carry the empty nymphal cases of stoneflies, recognisable by the paired tail filaments. The split in the thoracic segments marks the point where the adult insect eased its way out of the nymphal exoskeleton after the nymph crawled out of the water.

Stoneflies tend to be confined to fast-flowing, well oxygenated, unpolluted rivers, which is a pretty good description of this stretch of the river Wear between Wolsingham and Black Banks, in Weardale. Currently, after a long spell without heavy rain, the water level is low and mayflies are laying eggs in the shallows and pools.

Mayflies are the only insects that moult in their adult stages. The winged adult that emerges from the nymph is the subimago (known to anglers as a 'dun') and this undergoes a final moult to become the imago ('spinner' in angling parlance). This is an imago that appears to be laying eggs, and drowning in the process. Females have shorter front legs than the males.

Mayfly nymphs have three tail filaments but the adults can have two or three tail filaments, depending on genus. The hind wings in mayflies are much shorter than the forewings....

.. and both pairs are held vertically above the body when at rest.

There are two large compound eyes and three small ocelli in between them. Adult mayflies do not feed during their short lives, so there are no functional mouthparts.

Male mayflies are notable for their extremely long front pair of legs, which are used to grasping females during mating flights.

During emergence and mating flights low over the water surface, vast numbers fall victim to fish - especially leaping trout - while those that survive fish predation ...

....become food for birds like dippers, which also feed on the nymphal stages of stoneflies and mayflies.

Goosander and dippers

Downstream from the picturesque medieval village of Blanchland - see http://www.blanchland.org/ - Northumberland's River Derwent races over three kilometres of stony riverbed before it empties into the managed confines of the Derwent Reservoir. It’s perfect dipper habitat and today we mapped the territories of two pairs along this wild stretch of river. Mapping dipper territory is relatively easy – just follow them along the river until they do a U-turn and race back past you; they won’t cross into another’s stretch of river once ownership has been established. We never got close enough for a really good photograph, but close enough to record one of this bird’s remarkable features: white eyelids. When a dipper blinks its eyes go bright white. We also encountered a pair of goosander that are probably nesting along this stretch of the Derwent and just managed a shot of the handsomely-plumaged drake as it streaked past.