A trip to Holne Moor – cuckoos, scrub and flood prevention

I spent the afternoon yesterday with Kevin Cox, who lives in the Mardle Valley, is an RSPB Council member and heavily involved with Devon Birds. We talked about Devon birds, Devon Birds and the management of Dartmoor’s commons. Kevin has recently purchased part of Holne Moor from South West Water.

Holne Moor overlooking Venford Reservoir.

We went up to Holne Moor to have a look around. A very interesting visit for me. This is the key bird research area I have written about recently – the place where Exeter University’s Professor Charles Tyler, his team of research students and nest finders have been working (The Dartmoor Upland Bird Nest Group) – see here and here. This is the area where some of the key cuckoo research is taking place as well as being an area which supports high population densities of whinchat and meadow pipit.

The moor is grazed and has a swaling programme but does have quite a lot of small trees dotted around the landscape – cuckoos need these small trees so that they can survey the landscape and see where the meadow pipit nests are. On many commons now these dotted isolated trees are absent and new regeneration is now difficult due to the grazing and burning pressure.

The area is also very interesting as it gives a clue as to how natural flood management measures might work on Dartmoor in the future and play a part in ‘slowing in the flow’. South West Water have retained a belt of land around their reservoir at Venford. This area has been fenced off.

In this photograph you can clearly see the fence line – with grazed moorland to the right and the lightly grazed enclosure to the left. You can see that patches of light scrub have developed in the closure.

Here is another view of that enclosure.

These two photographs tell me a couple of things.

Firstly, if Dartmoor was not grazed, scrub and eventually woodland would quickly develop – the George Monbiot re-wilding scenario. Dartmoor is of course as I have said many times before an important historical and cultural landscape and therefore if the re-wilding scenario were to happen across the Dartmoor landscape then most of that would be lost. The landscape of Holne Moor is a good example of this as it has been ‘designated’ as a Premier Archaeological Landscape – see here for further details.

Jeremy Butler in his 5 volume Dartmoor Atlas of Antiquities sets out a detailed catalogue of the archaeological interest.

The map and accompanying text details the importance of the area from the Bronze Age, through the Mediaeval period to the present.

The challenge for all those involved with the management of such places therefore is getting the balance right between archaeological interests and biodiversity – both of which are of European Importance. I have written about this challenge before and it seems to prove intractably difficult to solve even though all parties are in fact pretty much in the same place – i.e. everyone wants a grazed landscape.

As Kevin Cox said to me on site yesterday (I paraphrase) – the archaeology has survived on here on Holne Moor for thousands of years through the ebb and flow of vegetation and farming cycles, however at the moment there is a biodiversity crisis and we may only have 30 years to save some species such as the cuckoo. Surely there is enough flexibility and goodwill within the system to tweak a few management techniques and thereby work out how to enable the cuckoo (and whinchats, meadow pipits etc) to flourish (e.g. ensure there are perching places and enough food for cuckoos) – the work that the Dartmoor Upland Bird Nest Group are currently researching.

The second thing that the two photos above tell me is how quick and easy theoretically it will be to naturally add regenerating trees and scrub to the landscape in very small but strategic places so that natural flood management schemes can help slow the flow. If enclosures were erected around specific stream valleys the developing scrub would quickly emerge and add ‘hydraulic roughness’. The areas of grazing land lost would be tiny and as long as the Commoners were compensated and not penalised as the current ‘ineligible feature’ nonsense currently would do then surely this too is a win-win for everyone.

I thought yesterday was going to be dominated by Storm Imogen – it certainly seems to have around our coasts but inland it was pretty windy but in my experience was mostly dry and allowed me instead to make a new friend, see a new place and think more about Dartmoor and its management.

 

More on Devon polecats

A couple of weeks ago I wrote about polecats around East Dartmoor – see here. Since then my colleague Mick Jones, the Lead Ranger for North Dartmoor told me that he had seen a couple of dead polecats on the A38 near Ashburton and collected the corpse of one of them. He has subsequently skinned the animal and prepared the skull as a specimen.

Frontal view showing the teeth

I was surprised how solid and how heavy the skull actually was

Top view – apparently polecats have a great deal of muscle around the neck

It is of course sad to hear that polecats are being run over on our roads but it is an indication of how many of them there now are in the county. Lets hope they continue to flourish and expand in their range. I have also subsequently heard from an old friend of mine from SE Devon that polecats are frequent roadkills also in East Devon and West Dorset.

A lazy Sunday afternoon

I’m having a lazy day! Just taken a few pictures of plants and insects in the lane where I live.

A dandelion’s year is almost over

This is a red campion even though it has pink flowers ….

These are hawksbeard flowers

And this is a common carder bumblebee

There’s always something to see down my lane…

Queen wasp at Parke in the winter!

We had an unexpected visitor in our office yesterday at Parke in Bovey Tracey – a Common Wasp Vespula vulgaris. It just appeared out of nowhere and started buzzing around the office – I expect our log boiler had produced enough heat to wake her up as she is a queen wasp. Surprising as there were very few wasps around last year.

I caught her in my butterfly net and then put her in this specimen tube

 

 

 In this picture you can see the distinct black spade like marking on the front of the face which distinguishes his species from other types of wasp

Just before Christmas we had a drone hoverfly in the office Eristalis tenax – this is a photo of the same species which I took outside in July  – it is a honeybee mimic

I also heard a report of two red admiral butterflies in our Widecombe Shop over Christmas too – all signs of our mild winter.

Just for the record – I let the wasp go and she flew off towards our Walled Garden.

Green and brown shield bugs

Most of the insects have now disappeared for the winter now but if you look in hedges and on bushes now you will still find some shield bugs – these insects over winter as adults which is quite unusual for an insect. Here are a couple of common species you will see on the edges of Dartmoor and the rest of Devon.

The Green Shield Bug (Palomena prasina) – a very common species

A brown shield bug Coreus marginatus – another common species – often found with the green shield bug

Inside the ice house

A few weeks ago I did a blog about cave spiders in the Bothy at Parke and mentioned the ice house in the grounds as another potential site for cave spiders.

Well the nice folks at the Dartmoor National Park Authority have kindly changed the rusted padlock so I have now been able to get inside and have a look around. The floor of the ice house is rather like a scene from The Hobbit – tangled, wet, dark and hiding all sorts of evil …. so I didn’t venture too far from the steps but I did manage to find what I was looking for!

The entrance to the ice house – new padlock installed.

I found six sets of cave spider (Meta menardi) egg sacs – here is one with an attendant female

Here is the male – about 3cm in length

The ice house was also home to this hibernating Herald moth – note the other tiny insect in the photo too – potential prey for the cave spiders!

 

Another couple of craneflies before the deluge

The weather has come in with vigour  this morning – I think the Devon drought has ended.

Before the weather arrived I managed to photograph this pair of mating craneflies (I think the species is Tipula maxima).

 

The wings are clearly mottled and it tends to live in wet woodlands – it is common throughout Britain. Whether are interested in creepy crawlies or not just look at the detail in this picture – nature is amazing down to the last detail!

The last few days of sunshine

The weather is forecast to change over the weekend but before then are still quite a few ‘summer’ insects on the wing. Here are a few from Parke yesterday.

This is the green leafhopper Cicadella viridian which is a pretty common and attractive bug which lives in wet meadows

A small copper butterfly sunning itself – 3rd brood this year

A common darter dragonfly – these insects will keep going until the first frosts

A drone fly which is mimicking a honeybee. These insects get sustenance from ivy  which is coming into flower right now – an important autumn source of nectar

Cant imagine I’ll be taking many more insect pictures this year ….

 

Daddy long legs everywhere

Over the past couple of weeks there have been large numbers of daddy long legs about. They have been in my house near Exeter and up on the high moor on Dartmoor.

‘Daddy long legs’ are also known as craneflies  – there are over 90 different species. This individual has a blunt abdomen – meaning it is a male

This one has a pointed abdomen – its a female. Craneflies on Dartmoor provide an important food source for various birds such a dunlin and meadow pipits

The species that is so numerous at present is Tipula paludosa. Looks a bit like something out of Star Wars!

Here is a close up – flies only have a pair of wings (bees have two pairs) in this picture you can see a stalk with a blob on the end below the pair of wings. This is known as the haltere – it is used rather like a gyroscope to help flies fly – it is also the ‘second’ pair of wings – all flies have halteres instead of the second pair of wings.

 

Bog bush crickets – doing well?

The bog bush cricket is a pretty rare animal nationally and one of its strongholds is south east Dartmoor and its hinterland. There are two colour forms – a brown animal with a green line on the underside of the abdomen and a brown form with green lines on top and underneath. They are pretty smart looking animals!

Here is a male with green on the top of the body – you can clearly see the reduced wings which are used to stridulate i.e. make the characteristic buzzing noise – when I photographed this individual at Chudleigh Knighton Heath (the Devon Wildlife Trust reserve) I could clearly see the wing cases moving.

This is the song of this actual individual singing recorded through a bat detector

Here is the brown version – another male – again at Chudleigh Knighton Heath

Here is the female – again a green form – note the long sickle shaped ovipositor – I photographed this individual in 2008 at Yarner Woods

Here is the distribution map of the bog bush cricket courtesy of the National Biodiversity Network

 Bog bush crickets are secretive animals and can be difficult to find. However using the bat detector their inaudible high frequency calls become audible and are a real help in locating individual males. One thing that has been obvious on my last few bog bush cricket trips has been the prevalence of another species – the long-winged cone-head in the same habitat. This is interesting as prior to 1990 long-winged cone-heads were absent from Devon (see here for the distribution maps) – on Chudleigh Knighton heath I would estimate that the cone-heads outnumber the bog bush crickets 3 to 1.

Here is a female long-winged cone-head (long sickle shaped ovipositor) photographed at Chudleigh Knighton – it was 12 ” away from the green male bog bush cricket above. This photograph demonstrates why they are called cone-heads
– their heads are shaped like a classic seaside ice cream cone!

Bog bush crickets appear to be flourishing and are common at their classic sites but I do wonder whether the cone-heads are having / might have an impact in the future- I guess time will tell and monitoring of their progress will be required.