Haven't I seen you somewhere before?

Once again I was caught by surprise.  I knew there was a sparrowhawk about because in the past few weeks I have been finding greenfinch and goldfinch feathers where he has made kills.  Two days ago I was about to go into the kitchen garden when suddenly there he was on the perch.  Each winter this window is set up as a hide with a rest for two cameras but this time I hadn't even cleaned the glass.  I went to fetch a camera and when I returned he was still there.  So I moved slowly into a position where I could get a photo.

It was amazing to be standing in full view of this bird only 3m away but I suppose he can't easily see past the reflections in the window and he only reacts to sudden movements.  In the end he stayed for over three hours, the last hour in pouring rain.  He flew off just before dark and I could at last go out to pick the vegetables.  Here he is looking a bit damp in the gloaming.

As soon as he had gone I cleaned the window and reassembled the camera platform inside the window.  First thing yesterday morning he was back on the perch and he stayed for two hours.  Here he is seen through a rain-streaked (but clean!) window.

He was back again in the afternoon, this time trying out a less obvious position at the base of the perch.

And later back on the perch.  I think this photo shows he is growing two new tail feathers (white-tipped and blue whilst most of the old tail feathers are brown).  If I am right this should confirm he is a second year bird.

It is difficult to be sure but I think I may have seen this bird before.  I wrote a post last year about how I thought I might be able to identify individual male sparrowhawks from the dark marks on the cere, the waxy-looking yellow structure at the base of the bill.  This bird has marks on his cere which are similar to those on a pale and scruffy-looking juvenile that turned up in the garden just over a year ago - one that was here for a only few days.  In addition the new sparrowhawk has a transverse nick two thirds of the way down the culmen, the upper ridge of his bill.  The bird last year also had a nick in the culmen, halfway down, but as the bill continues to grow to compensate for wear a nick like this would gradually move down.

If these are the same bird, the new arrival still looks rather pale and scruffy compared with some of the previous birds. He also has a more prominent supercillium (white "eyebrow") than is usual for an adult male, probably because he is only just over a year old.

Here he is compared with the very smart mature adult bird who was here all last winter.

The arrival of a new sparrowhawk has had a profound effect on the birds in the garden.  The  seed in feeder in the kitchen garden normally goes down by about 30-40cm a day.  Yesterday it went down by 2cm and today by about 5cm, even though I haven't seen the sparrowhawk today.  It will be interesting to see if he sticks around.

VoleCam

I had forgotten about the field vole living opposite the front door because the grass grew up in the "meadow" and the vole's network of holes and runs disappeared from view.  When I started to mow the meadow I found the holes again and they looked to be still in use.  So I put some apple cores outside to see what happened - and they disappeared. And of course I then set up a trail camera.  Often the vole is too quick for the camera and at first I put the apple too close to the hole so the camera didn't have time to react.  Putting the apple cores slightly farther away and not all in a run has allowed a few glimpses.

Field voles have short tails (～30% of body length) and are greyish brown.  Bank voles have proportionately longer tails (50%) and are a more reddish brown in colour.  Judging by their colour I am not sure these are all the same species but when I can see the tail it is short.  Watch for the last vole to appear when all the food has gone.  It is tiny and is a young field vole.

In a second sequence I think the first one probably is a bank vole because it is redder, slightly smaller with a slightly longer tail.

 The other is clearly a field vole.

Bank voles and field voles often live in similar habitats although bank voles prefer woodland edge / hedgerow places while field voles prefer long grass.  Here is sort of on the border between these two so it is no surprise to find them both.  The network of holes around the base of the oak tree is extensive so I expect there is plenty of room for them all below ground.

Comings and goings on OtterCam

Having the cameras in the culvert is a great way of keeping an eye on which otters are about because they are rarely seen in daytime, although one did swim right in front of me while I was eating my bacon sandwich the other morning. The cameras have picked up a powerful-looking lone animal a couple of times recently which I suspect may be a male on patrol.

The female and her pup use the culvert regularly.  This was just before midnight.  She is teaching the pup to kiss the camera as they pass.

The disadvantage when they head south is that they don't trigger the camera until they are half way down the pipe. When they head north we can see them go up the ramp.  This was just before dawn one morning.

And just after 06.00 on another morning.  On this occasion there were still wet footprints on the ramp and the gate when I looked two hours later.

This last sequence is puzzling.  The mother otter ran through the culvert on her own, calling for the pup.  When she reached the far end she could hear the pup squeaking from above.  She ran up the plank to collect it and they returned through the pipe.  I don't know which way they were heading in the first place or how they got separated.  The video ends with the obligatory sniff of the camera - I expect the otters recognise my scent by now.

CritterCam - the search for a water vole. Part 2

Following on from my previous post, this is the second report on my attempts to catch a water vole on a trail camera. The second camera was about 50m away from the first, the position of both cameras being determined by where I could get some field of view for them near water.  It was difficult because there was mostly just a trickle of water under the grass and rushes.  This was the position of the camera.

There were again plenty of views of voles but most were field voles. This time I used a 150mm cut section of reed as a calibration and unlike the piece of raspberry cane which was dragged off by the voles (I wonder what they did with it) the reed was ignored and stayed more or less in place.  Here are field voles near the reed.

Checking through the videos I did eventually see a larger vole.  Bank voles are 8-11cm long (head and body) with a tail 50% of body length, field voles are 9-11.5cm long with a tail <40% of the body length and water voles are 14-22cm with a tail 60% of the body length.  Obviously the young of each species are smaller.

Here is the calibration reed.

And here is the large vole with the same calibration line.  It measures about 14cm so it must be a water vole.

Unfortunately it doesn't show its tail on the video so we can't use that to check but it is too big even for a large field vole.  As you can see on the video it dragged the apple away and didn't show itself again.  At the start of the video a small vole dashes across, perhaps a bank vole or field vole.  The last clip is a very brief glimpse of a larger vole three days later.

So that is all I saw, not quite as exciting a video as I was hoping for.  There were lots of other brief views of small voles, which could have been bank voles or field voles or young of either species and more brief views of common shrews, wood mice and meadow pipits but once the apple had been dragged away there was nothing to tempt the voles out into view again.

I plan to have another attempt to get better water vole pictures next May when I am up there again.  I may try slightly lower down the stream in the hope of finding a bit more open water and a clearer view.  I think I'll also use larger pieces of apple so they don't disappear so quickly and perhaps fix them so they can't so easily be dragged into cover.  After the excitement of finding three shrew species on the other camera I may put down bait for shrews as well.

Water voles are widely but sparsely spread in this country and are rare in Northumberland.  The map shows sightings reported to iRecord in the last 20 years, indicated by small blue squares, mostly around the rivers South Tyne and Allen in the south west of the county.  This site (red arrow) is about 10km north of the South Tyne and 20km south-east of Kielder (green arrow).

The water vole is one of our most threatened mammals, having lost about 95% of its former sites and being classed as "endangered" on the Red List.  The population decline has mostly been caused by predation by American mink with loss and fragmentation of habitat as additional factors.  In an effort to reverse the decline the Northumberland Wildlife Trust has organised a water vole reintroduction programme - Restoring Ratty.  Since 2016 over 1600 water voles have been released around Kielder in the far west of the county.  Donor animals were collected from the North Pennines, Yorkshire and Scotland and taken to Devon for a captive breeding programme.  The offspring are brought back north for release around Kielder Water.

Kelly Hollings, Northumberland Wildlife Trust's Project Officer in the Restoring Ratty project, says that the released voles have migrated from their release sites to smaller streams and ditches so more recent releases have been in such places, perhaps similar to the one I have been investigating.

The site I have found is between the Kielder release site and established populations farther south.  With luck (and hard work by the Wildlife Trust) water voles will continue to spread and different populations will link up.  This experience also shows that in wilder parts of the country there may be a few more about than are known.

CritterCam - the search for a water vole. Part 1

This all began in May, when I was doing my bird count near the Wark Forest for the BTO Breeding Bird Survey.  At one point I glimpsed a small mammal running across the track out of the corner of my eye.  It was dark, vole-shaped and rat-sized so I wondered if it could be a water vole.  There is a very small stream running through a pipe under the track, no more than 300mm in diameter, and because of the dry spring weather there was almost no water flow.  The habitat is poor unimproved wet grassland with mostly rushes rather than grass at that point, not a habitat I associated with water voles.  (I used to see them 50 years ago in a slow-flowing lowland river.)

Although the BTO BBS records mammal sightings I wasn't confident enough to record a water vole.  I did, however, send a message to Kirsty Pollard, a water vole expert at Durham Wildlife Trust and she passed my email on to Kelly Hollings, Northumberland Wildlife Trust's Project Officer in the Restoring Ratty water vole re-introduction project in Kielder.  Kelly was very encouraging and said the habitat was good for water voles, similar to some of the release sites in Kielder, so I went back with three trail cameras in July.  The cameras were in for a week, one close to where I thought I might have seen a water vole and two on a slightly larger but still very small stream (<500mm across) a couple of hundred metres away.  They recorded hundreds of videos and on a first look through I couldn't see much very exciting.  There were lots of glimpses of small mammals and I could identify field voles and wood mice, as well as reed buntings, meadow pipits and a roe deer's ankles.

Before giving up I had another look through the videos and could pick out a few where the voles looked bigger.  They were all on the on the trickle of a stream where I had my first sighting and there was very little on the other cameras.  It is difficult to judge scale although there is a slice of apple visible in the first clip.  I sent a very brief extract to Kelly and she replied that she was 99% sure it was a water vole.

So I went back earlier this month with two cameras and put them both on the first stream.  In most places it is difficult to see any water at all as it runs underneath the vegetation.  I spent time clearing a view and making sure the apples were better positioned.  Between them the cameras recorded almost 700 video clips so it is taking a while to work through them.  The first camera was set up here.

There are plenty of images of voles but I think they are probably all field voles.  Bank voles are 8-11cm long (head and body) with a tail 50% of body length, field voles are 9-11.5cm long with a tail <40% of the body length and water voles are 14-22cm with a tail 60% of the body length.  On the video it wouldn't be easy to tell a field vole from a bank vole or a juvenile water vole without seeing the tail but in some images the tail is clearly visible and is short.  (The other name for a field vole is short-tailed vole.)  The first two voles in the video are small whereas the last one which appears briefly nearer the camera looks larger although it still clearly has a short tail.

I also put a piece of raspberry cane next to the apple, 150mm long to act as a scale but the voles didn't approve of my measuring stick and moved and then removed it.

One very interesting sighting was of three shrews - water shrew, pygmy shrew and common shrew.  You can see that shrews don't eat apple but they are very curious (and very fast).  To find all three species in the same place on the same night was a pleasant surprise.

There are another 390 videos from the second camera so I'll report back soon on those.

Cucumber green spider

A spider has featured on this blog only once before.  This little beauty is a female cucumber green spider, Araniella cucurbitina.  It weaves a small orb web in a bush or hedgerow and sits in the middle of the web, relying on its camouflage for protection.  The female is about 8mm across and the male is half that size,

This one had built a nest in the protection of a leaf curled over with silk.

Here she is spinning a silk thread and controlling it with a hind leg.

When last I looked there was second clump of eggs surrounded by silk and the spider had moved on.  Freshly emerged spiderlings are red and they change to brown in the autumn.