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Sunday, 21 September 2014

Willow Emerald Damselfly has reached Rainham Marshes

Five years since it was first discovered in Suffolk, the Willow Emerald Damselfly (Chalcolestes viridis) has been seen at RSPB Rainham Marshes.

A few weeks ago, a regular visitor, Dawn Cowan, took some pictures of an Emerald damselfly at the bridge in the Woodland. I thought that it was probably an immature Lestes sponsa, but after some discussion and close study of her images, the conclusion was that it was indeed C. viridis.
Then, 2 weeks ago, Tony Madgwick and I spent a day looking for and at suitable habitat in the hope of finding another one. We were about to pack up for the day when, next to the Cordite Store, we disturbed a large damselfly which then flew up into a tree. We got binoculars on it for only a very few seconds before it flew off, but we were pretty confident that it was a C. viridis.

On the same day, another visitor, Mark Philips, took a photograph of what was clearly a male C. viridis at the "Troll Bridge" . This is the where the boardwalk to the west of the Woodland does a zigzag across a ditch - between the Bog Wood and the Ken Barrett Hide.

The Thursday after that, encouraged by Mark's image, I spent some time at the Troll Bridge. I didn't see any damselflies, but I did discover some marks on a branch of the overhanging willow tree that I suspected were the galls that the tree produces when a Willow Emerald has laid eggs into it's bark. I consulted Tony and other experts at the BDS who confirmed that they were C. viridis ovipisition galls, and also suggested that they may be from last year!

Last Tuesday, I went back to the bridge hoping to shoot some video, and I finally managed to see a damselfly properly for myself. A male was perching on Burr-reed, quite unconcerned about me and several others watching. After about half an hour, two more - a male and a female in tandem - appeared. They flitted back and forth across the little ditch from the burr-reed to the willow tree, and even spent some time laying eggs into at least one twig of the tree.

Another female was seen close to the Purfleet hide on Thursday, and many people are still seeing the action at the Troll Bridge.

Willow Emerald is the only damselfly in Britain to lay eggs into the branches of trees - in particular trees which overhang water. It spends the winter as the egg, protected under the tree bark, and the prolarva then emerges in spring and drops from the branch into the water below. The larva develops over a period of just a few months, and the adult emerges towards the end of summer.

While we haven't yet found conclusive evidence of breeding at Rainham Marshes (only an exuvia or emerging adult would provide that), the appearance of oviposition galls and an ovipositing female is a good sign. It seems very likely that Willow Emerald is at Rainham Marshes to stay.

Saturday, 20 September 2014

Tall Ships passing Rainham Marshes after the Greenwich Festival

On the afternoon of 9th September, the Thames river wall at Rainham Marshes was full of people gathered to watch the Tall Ships pass as they headed out to sea after the grand finale to the Royal Greenwich Tall Ships Festival.

I equipped my camera with a wide-angle zoom lens and set up on a tripod. Through the afternoon I moved to various spots along the path to shoot some images for this timelapse.
I took a shot every 3 seconds, and ended up with a total of about 1800 images. I adjusted the exposure in Lightroom, then exported to 1920 x 1080 pixel jpegs. I used Quicktime to build a video clip for each different view and then Premiere Elements to edit together the video and add titles.
I've discovered since that Premiere Elements can import still sequences directly, so I can save the Quicktime step for my next timelapse.

Friday, 22 August 2014

At least 22 spots on this lovely little insect

I found 3 of these marvellous 22-spot Ladybirds (Psyllobora vigintiduopunctata) in Rainham Marshes' Cordite Store yesterday. It's not a rare ladybird, and is pretty widespread across the UK, but it's always nice to see one.

Apparently, they eat a lot of honeydew. I can't see what this one is eating, but I guess it might be something similar.
This isn't a fancy video. It's just a compilation of clips I shot while checking to see just how close I could get with the lens, extension tubes and extenders that I have. The ladybird is just 4mm long, so I got pretty close!

Saturday, 2 August 2014

Good news - we've found them!

A few posts ago, I was talking about the fact that few Lestes damselflies have been seen at Rainham Marshes recently.
In fact, the quite rare species, the Scarce Emerald Damselfly (Lestes dryas), which has been seen at Rainham in the past, has not been seen here for 2 years.
I spent several hours yesterday with Rainham's Warden and a couple of fellow volunteers out on Wennington Marsh searching for both the damselflies and any suitable habitat.

I'm pleased to say that we found both, though we only found 6 individuals in just one stretch of a shallow drainage channel. We weren't able to cover the whole Marsh, so we are hopeful that there are more to be found. Amongst the six were 2 mating pairs and another female ovipositing. I grabbed some images to check ID, and to show what we found.

You can see in these images that the drainage channel was full of emergent vegetation. This is how Scarce Emerald Damselflies like it. Large sections of the channel were also dry and, unusually, this is also beneficial to the damselflies. The larvae spend their time hunting in mid-level open water (all dragonflies and damselflies spend most of their lives in larval form in water), so they might be vulnerable to predation by fish. However, because their pond or ditch dries out by the end of summer, there are no fish! The damselflies get through the dry period in the egg, which the female had inserted into the stems of the vegetation (as you see her doing in the image above) and only hatch in Spring once the water level has risen again.

It would be great if we could have them back somewhere around the trail for us all to see, and I know that the Warden plans to manage some suitable areas for the species.

Thursday, 31 July 2014

Some more dragonflies

I've had a good week for dragonflies at Rainham Marshes, the highlight of which was finding a male Southern Migrant Hawker (aka Blue-eyed Hawker, Aeshna affinis) on Tuesday afternoon (29th July 2014).

I spent some 10 minutes watching this dragonfly hunting quite close in front of the Ken Barrett hide before I was sure what he was. I could see that he was definitely quite bright blue, but I wasn't certain until he finally perched.

Then I could clearly see the almost-solid yellow-fading to-blue colouration of the side of the thorax which confirmed him as a male affinis.
Our common native Migrant Hawker (Aeshna mixta) has 2 distinct yellow diagonal lines separated by a brown gap. A recently matured individual mixta can look almost as bright blue as affinis, but a view of the side of the thorax will separate the species.

I tried for an in-flight image, and this was my best effort. Don't look too closely, please, as it's not really sharp enough!

Southern Migrant Hawker - Aeshna affinis

I also made this black and white image of a Black-tailed Skimmer perching on one of the short dead reed stems in the "Dragonfly Pool".

Black-tailed Skimmer - Orthetrum cancellatum
I managed to find a viewpoint from which I could frame the dragonfly in-camera without any other reed stems in the shot, but I must admit that I didn't see the lovely wave pattern in the background until I saw the image on the computer.

Finally, this morning (31st July 2014), this female Southern Hawker (Aeshna cyanea) flew in to perch as I was walking through the Cordite Store.

Southern Hawker - Aeshna cyanea
I love to get images of dragonflies perched on interesting shaped plants, so this one fits the bill nicely. I also like the spider's web on the right-hand side.

Wednesday, 23 July 2014

Does twelve constitute a swarm?

Around one bush at Rainham Marshes RSPB yesterday, I found a group of about a dozen male Small Red-eyed Damselflies (Erythromma viridulum) perching on the leaves and flying around. They all seemed to choose the down-wind side of the bush, which made photography a little easier!

Small Red-eyed Damselfly - Erythromma viridulum

There was one female, but the males weren't paying her any attention.

Friday, 18 July 2014

A varied day at Rainham Marshes

Yesterday was my usual volunteering day at Rainham Marshes.
One of my tasks on a Thursday is to unlock the hides in the morning and lock them up again for closing time, so I always get around the nature trail at least twice.

Reed Warbler - Acrocephalus scirpaceus
On my morning round, this Reed Warbler (Acrocephalus scirpaceus) was singing in the reedbed by the Northern Trail. His chosen perch on the end of this Reedmace stem lifted him above the reeds and into the lovely warm morning light.

Next to him, a Reed Bunting (Emberiza schoeniclus) was also singing from the top of the reeds. I was struck by how I could see right through the raised crest showing how small his head must be under those feathers!

Reed Bunting - Emberiza schoeniclus
Later in the morning, I had reached the boardwalk between the brick targets and the riverwall turnstile. On Tuesday, folks had seen a family of Weasels playing along the boardwalk. I was hopeful, but didn't really expect to see them. Luck was on my side, however, as a youngster bounded along the trail towards me. I fired off some shots, but never got a decent focus. She disappeared into the grass. Then a second appeared up ahead, but seemed not to be as bold as it's friend, and stayed partially hidden under the side rail. It popped out for a few moments to study me, and I finally managed to get an image in focus - shame about the grass stem, though!

After lunch, I decided not to walk all round again, but to spend some time in the Woodland and then the dry grassland by the Ken Barrett hide.
On this occasion, the Woodland wasn't very productive of images, but the meadow, in full sun, was alive with feeding butterflies and hunting Ruddy Darters (Sympetrum sanguineum).

The Darters, as they usually do, were perching on the tops of prominent plant stems where they could get an all-round view. From this vantage point, they could fly (dart, in fact!) to chase any potential prey.
Dragonflies will generally only fly in warm, sunny weather. They like the heat, but, it is possible for it to be too hot even for them. Another characteristic of the Darters in very hot sunshine is that they will raise their abdomen and point it towards the sun to reduce the surface area that is exposed to the heat  - this is called  "the obelisk position".
That's what this male Ruddy Darter was doing.

Ruddy Darter - Sympetrum sanguineum

The area was also full of butterflies feeding on the nectar of Ragwort flowers. There were Gatekeepers, Small and Essex Skippers, and this lovely little Brown Argus (Aricia agestis).

Brown Argus - Aricia agestis

Wednesday, 16 July 2014

A Migrant Hawker - not the end of summer!

I love Migrant Hawker dragonflies. Males searching for a mate will often pause their cruising flight to hover for a few moments, offering me an opportunity for a decent flight image.

Migrant Hawker - Aeshna mixta
I captured this image of a hovering Migrant Hawker in late August 2013

I often think of my first Migrant Hawker of the year as a sign that the end of summer is approaching. I refuse to think so this year, as I've already seen my first one, and there's lots of summer still to come!
As I was walking through the Woodland at RSPB Rainham Marshes yesterday (15th July), I saw a medium sized dragonfly fly past me and perch under a branch of a hawthorn next to the path. The choice of perch already suggested that it was a hawker, but it was clearly much smaller than the Emperors that I'd been watching all day.

It only took a few moments of viewing through binoculars to confirm that it was an immature male Migrant Hawker.
an immature male Migrant Hawker at Rainham Marshes on 15th July 2014

Sunday, 13 July 2014

Wild sounds from my archives - an early spring morning in an English Lake District valley

Not much more than a mile north of the village of Coniston, in the English Lake District, is the small side valley that leads to High and Low Tilberthwaite. 

You're never far from Yewdale Beck anywhere in the first mile of the valley and, travelling up the minor road on the eastern side, you soon pass right next to it.

Early one May morning, I set up my microphones on the bank of the beck.  At this point, the beck is about 5m wide, tumbling over a bed of rocks and pebbles.

A little further up the valley, the road passes into oak woodland. On a sunny spring morning, the colour of the light under the trees is a rich green. The soundscape is full of green birds, too. 
Here is a Wood Warbler (Phylloscopus sibilatrix) singing high in the trees, just below the canopy. The descending trill and the piping are both his calls, and he sings as he flies between branches.

Even further up the little valley road, we come to the extraordinary scene of Hodge Close, a disused slate quarry. The hand of man is obvious everywhere. Rusty machinery, square-cut blocks of rock and, most impressive of all, a large deep quarry hole, 150ft deep with a blue pool at the bottom.
The wildlife doesn't seem to mind! On this particular morning, I heard Tree Pipit, Garden Warbler and, at the top of a tall conifer tree, this male Redstart (Phoenicurus phoenicurus).

Wednesday, 9 July 2014

Emerald Damselflies at Rainham Marshes - coming soon?

I don't really know why, but I've not found any Lestes damselflies, the Emeralds, at Rainham Marshes in the last couple of years - despite looking for them.

Rainham Marshes has been known for both Lestes sponsa (the common Emerald Damselfly) and the much rarer Lestes dryas, Scarce Emerald Damselfly, which can be found in well-vegetated ditches and pools at sites along the Thames estuary.

We're not yet in the main season for either species, but I've been very pleased in the last couple of weeks to find a total of 4 individuals of Lestes sponsa - a male and 3 females. I've not found any dryas yet, but I'm still looking!

Here's a female Emerald Damselfly (Lestes sponsa) from yesterday (8th July 2014)

Emerald Damselfly - Lestes sponsa

Friday, 4 July 2014

A Jewelwing at Cornmill Meadows

My latest imagea male Banded Demoiselle (Calopteryx splendens) at Cornmill Meadows Dragonfly Sanctuary
Banded Demoiselle - Calopteryx splendens

Monday, 30 June 2014

Pink spots on metallic blue

A beautiful day-flying moth... Six-spot Burnet - Zygaena filipendulae.

Six-spotted Burnet Moth - Zygaena filipendulae

Friday, 27 June 2014

Just a moment to rest

My latest imagea male Banded Demoiselle at RSPB Rainham Marshes.

A turquoise flash and an orange splash

My latest video - the male Kingfisher who successfully raised chicks at RSPB Rainham Marshes earlier this year.

Sometimes, you just have to be lucky

My latest sound  - a Great Reed Warbler that I was lucky enough to find at Westwood Marsh, Suffolk, on 16th May 2014.