Heatwave in April..

The next few days saw the Riverside gradually heat up, with unique weather conditions bringing a short-lived false start to summer.

The 15th April 2018, after a cool night, was overcast with dark clouds and threatening rain - however the riverside was again lively with a blackcap singing in Blackthorn but in a different location to the previous day whilst a buzzard circled over the river, gradually coming closer. A treecreeper flew across low to the base of a bare tree and worked its way upwards. Wrens, blue tits and great tits were calling and a fine male bullfinch flew across from a 'house sparrow hedge' where the colony was singing, into a hawthorn on the opposite bank. A great-spotted woodpecker called from a bare ash tree whilst below, a robin was collecting some fresh green leaves, carrying small bunches in its beak from the river bank up into an ivy-clad mound. A song thrush was seen bathing for some time in the river, perching on a floating twig island. It then flew off to a higher branch to preen and dry off.

More windy and damp days followed - but by the 18th it had become considerably warmer and at last butterflies emerged, firstly a fast-flying male Orange-tip showing up brightly over fresh green bank vegetation, then a brilliant male Brimstone butterfly.

Cuckooflowers were now appearing in clumps along the banks and in the wild field - an important food plant for the Orange-tip caterpillar :

Cuckooflower (or Lady's Smock) on the river bank April 2018. 

Orange-tip females will be ranging the river banks selecting these plants on which to lay their eggs.

The butterfly caterpillars will then feed on these during the summer. They will then leave to hide in dense vegetation to pupate and spend the coming 10 or 11 months in chrysalis form before emerging as adult butterflies in April the following year.

The following day, 19th, was very hot and sunny and many more of these butterflies were seen.   

Friday 20th April was another very fine day with the opportunity to do a survey of the South area during the morning as so much was happening. The full survey covering north and south will following the next post.

On 20th there were no clouds, a very slight breeze, the grass slightly damp with dew. The river level was lower but still fast-running. A large old oak was just coming into leaf, together with the Hazels and Willows. Wild Garlic was found growing in some new places together with Lesser Celandine almost certainly due to the upper storey remaining bare longer than usual allowing light on the under storey. Blackthorn was now covered in dense blossom and the grassed areas covered in brilliant Dandelions.
One can only hope that the profusion of wild flowers is allowed to flourish and provide pollinators with sustenance during the Spring.
House Sparrows singing  were encountered in their traditional colonies, in hedgerows, bramble patches and banks (about 60). Wood pigeons were not numerous, only 9 were seen, mostly in pairs. A pair of Carrion Crows were balancing in a tree top whilst a buzzard called from oaks on a wooded margin. Three jays were seen and heard chasing, with three magpies taking flight, the jay in this case being the more aggressive species. A nuthatch was heard calling loudly and continuously - the calls directed at unwelcome attention - it obviously has young to protect in the nest. Its mate was seen briefly amongst the branches (2).  Blackbirds were also vocal in protecting nests (14) or foraging in the damp grass and mud on the banks , with a single song thrush seen in deep shadows. Dunnocks are normally found lurking under vegetation in shade but today four were easily seen, two singing from prominent song posts.
Blue tits (34) were active with a few singing or calling and great tits (15) were easily seen when calling loudly but with some flying silently low over the river to nests in old tree roots. Robins were definitely nesting as fewer were seen than usual (10) but those seen were singing strongly. Goldfinches (about 17) were gathered in a loose group high in an old Maple, singing to themselves, occasionally flying out to forage.
A single male bullfinch gave a fine view, intent on feeding, gorging on the Blackthorn blossom near the top of a thicket, not easy to miss in the bright sunshine, balancing by flapping it's wings.

Blackthorn Blossom along the river April 2018

Warblers were doing well, with blackcaps (5) singing from the dense blossom of Blackthorn thickets and others from Willows just coming into leaf.  Song from Chiffchaffs (7) was the most penetrating - heard from just about every corner - not always the simple 'chiff-chaff' but sometimes  with 3 syllables such as 'chiff chiff chaff'. Just one willow warbler was seen, its song unmistakeable. Wrens won the day for singing however with 18 along the length of the river banks; there were certainly more present but nesting.
The most welcome were the common whitethroats which have arrived in good time, settling after their long journeys in their usual habitat, the bramble and low tangled scrub,  their songs also clear (4).
Butterflies - the first Commas were seen flying over young nettles on the banks and numerous Orange-tips were seen ranging along the banks, mostly males (orange wing-tips) looking for females. Peacock, Brimstone, Speckled Wood and Red Admiral butterflies were also seen. Large Bombus terrestris bumblebees were quite numerous as were smaller bees feeding on the numerous wild flowers and blossoming trees. Hoverflies were present in good numbers too.
A very active morning - and more for the end of April to come.