Saturday, 25 October 2014

Week 40: Harrier in Hemel, Migrant Search & Territorial Kingfishers

Young Female Kingfisher in Horse Chestnut on Bulbourne Meadow, overlooking the River Bulbourne

This week, we start off 2.5 miles from Box Moor Trust land, in a Horse Paddock. This is no ordinary Horse Paddock. It is to Interesting Birds what my garden is to the Local Cat Population, irresistible. Dan Forder is passionate about local birding and has spent innumerable hours in the field in and around Hemel Hempstead. When most of us would have given up and headed to Tring reservoirs, Maple Lodge or Tyttenhanger gravel pits, Dan has persevered. His patient dedication has continued to pay off and, over the past few months, at The Horse Paddock, he’s found Wheatears, Whinchats, Stonechats and a Tree Sparrow to name but a few. This week, Monday morning, the Horse Paddock had a new arrival for Dan. A Black Redstart! This is another passage migrant in Hertfordshire and, if not the first record for the Hemel area, it is not far off it. I got there at about 10:30am and, with Dan, excitedly watched the flighty Black Redstart and a couple of Stonechats. Photographs and details of the find are on Dan’s excellent blog here and here.

Spurred on by the presence of a Black Redstart locally, I opted for the Brickworks next. Black Redstarts favour industrial habitats so I hoped that the buildings and brick piles might have lured a second bird down for a pit stop. It wasn’t to be and, although I checked through 3 lively mixed Tit flocks, I couldn't conjure up a Yellow-browed Warbler either (another passage migrant, two of which had been reported at Amwell HMWT near Hertford). The mixed Tit flocks were mostly made up of Goldcrests, Blue Tits, Great Tits, Coal Tits and Long-tailed Tits but one also had a Nuthatch, another a Chiffchaff and also a few Chaffinches. Over head, I heard passage Skylarks and Meadow Pipits and around the Brickworks there were still numerous Hornets, bashful Bullfinches and chirpy Robins.

Home for some lunch and then out again to visit the Oak and Westbrook Hay. The Oak’s leaves are just beginning to take on their Autumn colours.

I searched high and low for migrants but except for an influx of Woodpigeons (really, really not what I was after), all I could find were 3 Redwing in the bushes by Preston Hill pond. Feeling worn out and deflated, I trudged back down hill to the car park at be greeted by Dan! He’d just arrived having spotted a Marsh Harrier from his office window in town. There’s a moral/lesson/joke-at-my-expense in there somewhere, I’m sure. Anyway, the bird had flown west and circled over Bulbourne Moor before moving out of sight. We made for higher ground and searched the valley and skies but couldn’t relocate the bird. Remarkably, the following day, Dan received a report that a Marsh Harrier had been spotted roosting on the gas towers by Roughdown Common. This is a great record for Dan and the Box Moor Trust and I only wish I’d seen it.

Tuesday morning, in near gale force winds, blissfully ignorant of roosting Marsh Harriers, I searched Roughdown Common. I found more than 25 sheltering Redwing and couple of Bullfinches before deciding enough was enough and taking shelter myself back home.

By Wednesday, I was worn out. I checked Roughdown again and took a leisurely stroll east along the river Bulbourne from Station Road. I’d walked across Bulbourne Meadow and was just about to carry on down river when I heard Kingfisher calls. I turned around and there, perched in the reflecting willow, were two Kingfishers, facing one another and posturing. Unfortunately, their territorial negotiations were almost instantly disturbed by a passing dog walker but the young female bird didn’t go far. The other bird was a male and I think possibly an adult male rather than the young male observed recently. I heard a third Kingfisher behind me down river. It really is wonderful to have these birds resident: feeding, breeding and thriving here.

I stayed a while and watched the young female fishing from the trees. She was very successful and it’s no wonder she is perhaps reluctant to move on from this territory.

Catch it

Lob it

Stun it

Position it

Bash its head in

Line it up and swallow it down

She looked remarkably pleased with herself having caught, killed and necked that little fish!

Saturday, 18 October 2014

Week 39: Eyes on the Sky & Caddisfly

View NW from Barnfield, over the SW end of Dellfield towards Ryders

"Good morning, Eeyore," said Pooh.
"Good morning, Pooh Bear," said Eeyore gloomily. "If it is a good morning, which I doubt," said he.
"Why, what's the matter?"
"Nothing, Pooh Bear, nothing. We can't all, and some of us don't. That's all there is to it."
"Can't all what?" said Pooh, rubbing his nose.
"Gaiety. Song-and-dance. Here we go round the mulberry bush."
Winnie the Pooh by A. A. Milne 

It has been a week of grey gloom to rival anything lovely Eeyore might mutter. I confess I’ve not been immune to the dampening of spirits as the rain and low cloud have arrived, lingered and made themselves at home. However, it is Autumn migration and that really can be exciting, no matter how grey a day it is. On Wednesday morning, I plodded up to Westbrook Hay. The previous evening, there had been a report of a spectacular nocturnal migration of Thrushes over Berkhamsted, involving hundreds, if not thousands of Redwing and Song Thrushes, all heading south for the winter. I wasn’t quite sure what to expect at 10 o’clock in the morning, 2.5 hours after dawn, but you never know.

On arriving at Dellfield, I spotted at least 7 Mistle Thrushes with a couple of Redwing and Green Woodpeckers amongst them. All making the most of the damp earth and the worms which had been forced closer to the surface to avoid drowning. There were also some 20 Magpies and a small group of 12 Woodpigeons feeding on the meadow. All but the Redwing are resident birds.

With my eyes and ears well and truly open to the possibility of migrants, I made my way up through Dellfield, through Barnfield and on to Bovingdon Reach. I think I was still on Dellfield when the first flock of c100 Thrushes came over, heading northwest. Unusually, they were silent. I was expecting to hear the seeping of Redwing or the chacking of Fieldfare but I heard neither.


Over the course of more than an hour at Westbrook Hay, I recorded the following flyovers:

Part of one of the flocks of Redwing over Dellfield. 59 birds counted.
Quite possibly the worst photograph to appear on my blog
400+ Redwing over in groups of 60-100+. Mostly heading west/northwest. I suspect this is a very conservative count and I underestimated the size of the flocks.
3+ Meadow Pipits (heard)
2+ Skylark (heard)
8+ Chaffinch
150+ Starlings
2 Pied Wagtail (heard)
1 Swallow over north. I do hope he turned around at some point!

Other resident species noted
21+ Goldfinch
45+ Woodpigeon
70+ Starlings
8 Green Woodpeckers (they were surprisingly visible due to the damp earth and the availability of food).

Although the weather was dank, dark and grey, it was an exciting morning, with swathe after swathe of birds moving through. It was lovely to hear the Skylarks and Meadow Pipits flying over too. These are species which are mostly absent from Box Moor Trust land, something which I think the Trust hope to address. However, Meadow Pipits have been moving through on migration over the last couple of weeks (I heard them regularly whilst I was filming the Stonechat) and I enjoyed their chirpy presence albeit temporary.

Thursday, I managed a short visit to the Brickworks. It was a morning of countless Hornets, a Red Admiral, a Comma and at least 6 singing Robins setting up winter territories all within a small area.

Finally, on Friday, I followed up on Dan’s sighting of 5 Siskins at the Gadespring Cress Beds. The site isn’t open to the public but it is Trust land and I just wondered if the birds had stayed in the area. Unfortunately, the answer was no but I did walk into a mass emergence of Caddisflies, specifically Limnephilus lunatus. Its name, “lunatus”, derives from the Latin for half-moon-shaped and refers to the crescent on the rear edge of the wing.

    Caddisfly (Limnephilus lunatus)
    Caddisfly (Limnephilus lunatus)

This is an order of insects, Trichoptera, I’d not really looked into before. They are closely related to moths and butterflies, Lepidoptera, but instead of scales (Lepido) on their wings they have hairs, hence Tricho = hair and Pteron = wing. There are approximately 7000 known species of caddisfly, nearly 200 of which occur in the UK.

Much like the Craneflies, they go through a yearly life-cycle, with the adults only lasting 1-2 weeks and, within that time, they live to breed and lay eggs (it’s another species which rarely eats as an adult). The eggs are laid in a water body, in this case, the cress beds at Gadespring and within a few days the young larvae hatch. These go on to form protective casings around themselves, in Limnephilus lunatus this is constructed from plant materials, with their head and thorax protruding from the end so that they can feed.

When the time comes to pupate, the larva attaches its casing to a solid object in the water and closes up both ends for further protection. Within a few weeks, having munched its way out of the cocoon, the adult emerges.

Although Caddisfly can exist in poor quality waterbodies their presence in abundance is generally a good indicator of clean, unpolluted water. I’d say the latter applies to Gadespring. They are also a great source of food for other animals. “Freshwater fish, particularly trout, and eels feed on larvae and swimming pupae. Trout, birds, lizards, frogs, spiders, dragonflies, and bats feed on adults.” (Britannica)

Last year, I visited Thetford in Norfolk to see the Black-bellied Dipper, a rare visitor from the continent which had overwintered on the river Thet. Its primary food source was caddisfly larvae. It would routinely fish out a beak full of leaves (aka a caddisfly casing) and proceed to bash it apart to reveal the larva within. It was fascinating to watch and it demonstrates wonderfully the importance of clean water streams and rivers, and the creatures they support.
    Phase 1: Fish out the leaf casings
    Phase 2: Bash leaves apart

    Phase 3: Larva peaking out of leaf casing ready to be extracted
    Phase 4: Eat larva within

It’s a shame we don’t get Dippers around Hemel!

I should round things off with arguably the most gloomy, Eeyore inspired Oak photograph this year.

Saturday, 11 October 2014

Week 38: Juniper - A Hint of Hogwarts in Hemel

Autumn leaves in a puddle in Hay Wood

I might have got you here under false pretences (oblique references to Harry Potter can do that) but it’s all in a good cause. I had to think of an appealing characteristic of slow-growing, unchanging, small green trees which, if you’ve walked Roughdown Common for a number of years, might just as well be covered in the cloak of invisibility. I’m referring to the modest but locally unique population of regenerating Juniper (and that wasn’t a nod to Dr Who, I promise). In fact, it’s “one of the best populations in the County” according to page 98 of the Dacorum Landscape Character Assessment. Nationally, Juniper has been steadily declining and is a priority species under the UK Biodiversity Action Plan. The destruction and loss of chalk downland, one of its preferred substrates, is likely a factor but more worryingly, according to the Woodland Trust, “it appears that the plants are unable to regenerate successfully - [lack of TARDIS notwithstanding] this problem is partially attributed to browsing of foliage by deer and rabbits. Juniper may also be affected by Phytophthora root rot and has recently been found to be susceptible to Phytophthora austrocedrae, a fungus-like organism which infects the plant via the roots and causes foliage to decline and eventually die.” Put into context, it soon becomes clear that the healthy, regenerating population at Roughdown Common is genuinely precious (echoes of Lord of the Rings reverberate around my head). Given its scarcity and value within the Box Moor Trust landscape, it had to feature within a blog post…

Juniper’s appearance has always seemed beautifully gothic, and evokes in me thoughts and emotions associated with the magical; with witches and wizards and wispy shapes within the darkness. Actually, according to the Woodland Trust website, “Juniper is considered to be a deterrent against the devil and witches. It was hung over doorways on the eve of May day and burnt on Halloween to ward off evil spirits. It was said that you would prosper if you dreamed of gathering juniper berries in winter".

I've photographed the Junipers in daylight, when the berries glisten, but I reckon their shape and texture is best revealed when illuminated against the darkness…

Aside from its scarcity and beauty, the dense foliage of Juniper provides great nest sites for little birds like Goldcrests. It’s also the larval foot plant for a number of moths, including the Juniper Pug (Eupithecia pusillata), Juniper Carpet (Thera juniperata) and Chestnut-coloured Carpet (Thera cognata). The mothing team recorded Juniper Pug this year but I’m not sure about the Carpets. As for the berries, Thrush species get to snack on those. One website even mentioned that Ring Ouzels like them so I shall have to keep my eyes peeled as Autumn migration progresses.

Speaking of migration, I have been out searching for Hoopoes, well, one would have done. Thursday morning, I walked from Dellfield, through Snook’s Moor, Snoxall’s Moor, Herdsman’s Moor, Fishery Moor and Station Moor and up into Roughdown. Forty miles away, up at a Willington (near Bedford), there’s been a Hoopoe hanging around all week (photographed below). And, you get to wondering whether it brought any friends along and, if so, where did they end up? Hemel moors are as good a place as any. Unfortunately, I couldn’t even rustle up a Yellow Wagtail amongst the cattle. Not to worry, it kept me distracted. With the drop in temperature and change in weather, I am fighting the urge to build a nest of duvets and pillows and snuggle up à la Edible Dormouse.

Finally, this week's Oak photograph, catching the leaves before they dry up and fall.

Wishing you all a week of sweet juniper-berry-filled dreams.

Saturday, 4 October 2014

Week 37: Migrant Stonechat & Sibling King

Stonechat (Saxicola rubicola) (video grab)
Over the last week, it has been raining Stonechats…sort of! Dainty, orangey-brown puffs of down have been turning up in unusually high numbers, sitting pretty on prominent perches and showing themselves off to all and sundry...if you’re lucky. Ordinarily, a handful on Ivinghoe Beacon constitutes a good year. Last week, 19 were reported in one day! Dan of Hemel Birding found at least 3 at Water End, near Great Gaddesden last week. And, if ever there was a chance for one to turn up on Box Moor Trust land it was now, following what has obviously been an extraordinarily good breeding season. They are a resident species in the south and west of the UK but only really present in Hertfordshire during passage migration, with a few birds over-wintering. Their name, I guess, stems from their call, which starts with a whistle and ends with what sounds like two stones being bashed together.

Wednesday morning was my first opportunity this week to get out around Box Moor and I headed for Roughdown Common. I scoured all the obvious places a Stonechat might hang out and some not so obvious ones, just in case. I walked the moors, from Station Road to Two Waters Road, scanning the fence lines for bundles of feathers propelling themselves up into the air (or down onto the grass) to catch insects. No sign. However, I did come across a good dozen Common Darter dragonflies (Sympetrum striolatum), including a mating pair, on the river Bulbourne in exactly the same area that the damselflies had frequented in June. There is obviously something about the habitat in this location which is just right for damsels and dragons.

Wending my way back upriver, to the area which the Kingfishers favour (just downstream from the footbridge and weir between Harding’s Moor and Bulbourne Meadow), I got lucky. A Kingfisher was perched on a branch, attention firmly on the water. I inched my way nearer, trying to keep myself hidden, eventually getting as close as the cover would allow. I had about 90 precious seconds with the bird before we were disturbed by walkers and the encounter evaporated. But, more on that to follow.

Back to the Stonechat search. Thursday afternoon, off I went to Westbrook Hay. Dellfield had been transformed by the hay cut and, having photographed the Oak, I thought I’d just check Bovingdon Reach meadow for Stonechats or other migrants. It’s not difficult to imagine my delight when, up ahead of me, I saw a little bird fly up into the air and come back down to land on the top of a bush. It was unmistakably a Stonechat, enjoying the flies and insects accompanying the sheep, grazing the meadow. It was favouring the small “island” of vegetation on the south-east side, near Hay Wood. The next hour and half were spent watching and filming the immature male (fledged this year) as he fed on Hawthorn berries and tasty morsels plucked from flight and, on a couple of occasions, looked as though he was about to explode (you'll see what I mean if you watch the clip…). [The HD version is available on Vimeo: just click the HD button, bottom right corner, and follow the link]

Ok, returning to the Kingfisher story. The bird I saw on Wednesday was obviously a male but it wasn’t until I got home and went through the photographs that I was able to put the bird in context. It is in fact another immature bird (white tip to the bill and dark tops to the feet/legs) and is likely the sibling of the immature female I saw last week. He has a slightly deformed/damaged lower mandible, which will make him easy to identify in the near future. It really is fantastic news that the resident adult pair managed to successfully raise at least 2 fledglings this year.

Below are a series of shots of the young male as he preened. Heavy crops and backlit but I thought them worth sharing. I watched the bird dive into the water; emerge; settle, and then set about sorting out his feathers. Wonderful stuff.

This week's Oak photograph and Dellfield after the hay cut

Finally, the mothing team have trapped on Trust land a few times in recent weeks. You can read Ben’s latest reports and enjoy their best finds here and here.