Friday, February 15, 2013

Jack Snipe study.

Recently, when the weather has permitted, I have been trudging around suitable local habitat looking for Jack Snipe. I know that they are around but they are not always easy to locate. Common Snipe, too, have been thin on the ground. I've had a couple of birds shoot out of the vegetation but the pointy wings, white trailing edge to the wing, characteristic zig-zag flight and silly squeaky noise all point to definite Common Snipe. I was explaining to a mate that Jack Snipe have a different flight when flushed and that they only flush when almost crushed under a welly when he asked what was the best ID feature when they are on the ground. Having a few O.K. photos of Jack Snipe I thought I'd use them to try a little ID feature to help.
This first photo of a Jack Snipe's head shows the quite detailed head pattern. There is an obvious split supercilium i.e. two buff lines bisected by a rich brown line above the eye. Common Snipe lacks this feature as you can see in  photos 2 and 4. There is also a brown crescent running under the eye of the Jack Snipe which meets the brown eye-stripe behind the eye. If you look at photo 4 you can see that the brown mark under the eye of Common Snipe is obvious but does not extend upwards behind the eye.

Jack Snipe Lymnocryptes minimus showing deep based bill and head patterning

Snipe Gallinago gallinago showing the pale median crown stripe
Some guide books suggest that Jack Snipe has a dark loral patch but I think that Common Snipe also has a dark loral patch so this is not much use as an identification point in the field. What is striking is the green glossy back and the obviously straw-yellow tramlines of the Jack Snipe which can be seen well in these photos. The Common Snipe has whitish stripes on a more subdued brown mottled back.
Jack Snipe Lymnocryptes minimus showing the all dark crown without median crown stripe.
These two pictures show the difference in the length of the bills. The Common Snipe has a very, very long bill that, to me, always looks a bit unwieldy whereas the bill of the Jack Snipe looks a lot more sensible as it is much shorter and thicker at the base. Both of the pictures of Common Snipe show that the breast and the flanks are quite heavily barred. The Jack Snipe shows streaking in these areas but you can't see this in these photos as the bird stubbornly refused to turn around!

The famous bobbing-up-and-down feeding action of the Jack Snipe is not much use if the bird you see is not feeding and to be honest I've never seen one feeding, they are always flying away or pretending to be totally invisible in the vegetation.
Back to that flushed flight...if it takes off silently from under your boot, frightens the bezeesus out of you, has a very pointed tail and then shoots back into the vegetation not too far away it's almost certainly a Jack Snipe. On the other hand if it's flight is really erraitic, it squeaks and zooms off over the horizon chances are it was a Common Snipe.

Monday, February 11, 2013

Pheasants and Buzzards: Pt 2

A few weeks back I posted a piece on the shooting of buzzards and the increased pressure on this species imposed by pheasant rearing landowners and keepers. You may remember that towards the back end of last year the government proposed and then rapidly withdrew a a plan to "sub lethally" control buzzard populations to limit losses of pheasants. Last week I was handed a paper on this subject and I think it makes for interesting reading. Titled "Pheasants, buzzards and trophic cascades." and written by A. C. Lees, Ian Newton and Andrew Balmford it was released about four months ago. I'm not sure where I stand re. copyright but I would like to quote some of this paper.
The Abstract sets out the discussion quite succinctly: " The partial recovery of large birds of prey in lowland Britain has reignited conflicts with game managers and prompted a controversial U.K. government proposal to investigate ways of limiting losses to pheasant shooting operations. Yet best estimates are that buzzards are only a minor source of pheasant mortality - road traffic, for example, is far more important. (How many road kill pheasants do you encounter on an average rural drive?) Moreover, because there are often large numbers of nonbreeding buzzards, local control of breeding pairs may lead to their replacement by immigrant buzzards. Most significantly, even if successful, lowering buzzard numbers may directly or indirectly increase the abundance of other medium-sized predators (such as foxes or corvids) which potentially have much greater impacts on pheasant numbers.

Buzzard Buteo buteo. Guilty of a minor impact on pheasant numbers
When Wildlife Minister Richard Benyon suggested that buzzard numbers could be controlled by nest destruction and translocation the general public and conservation NGOs were not pleased. When he changed his mind (not a U-turn!) it was time for the Countryside Alliance and similar outfits to get annoyed. Between 20 and 35 million pheasants are released by the shooting industry annually, adding to the wild bred stocks. The paper uses a case study of 486 reared pheasants that found that 37.5% were shot and 36% predated or scavenged - principally by foxes. "In this study, raptors were implicated in the deaths of <1% of individuals." Another study in Dorset found that 5-13% of pheasants are killed on the roads.

Conceptual map of interspecific interactions taken from the paper by A.C.Lees et al.

"It is estimated that for each paired buzzard in southern Britain there are up to three additional non-breeding birds (Kenwood et al 2000)" So get rid of your local buzzards and more will soon move in. "Two recently prosecuted Shropshire gamekeepers discovered the extent of such immigration for themselves when they illegally killed over 100 buzzards on one estate in less than six months (Evans 2008)" Over 100 buzzards in less than six months!! Anyone who likes to see a buzzard soaring overhead will no doubt have a strong reaction to news like this.
Ring-necked Pheasant Phasianus colchicus 20 - 35 million released in Britain every year.
An interesting point made by the authors is that : "Although buzzards may have a minor negative impact on game populations by direct predation, this may be more than compensated by buzzard predation on other predators such as corvids which, through nest predation, may have significant impacts on the reproductive success of the wild breeding stock of pheasants." The authors go on to point out that rabbits cause damage reckoned at £180 million annually - and we know what buzzards do to rabbits! Removing buzzards may impose subtle economic penalties on land-owners as well as leading to increased numbers of foxes, which kill at least four times as many pheasants as do buzzards.
Fox Vulpes vulpes. The main predator of Pheasants
The main concern of most people who are not stakeholders in the pheasant business was that the Benyon proposal: " would inadvertently give the greenlight to wider raptor persecution - this at a time when illegal persecution already looks set to drive Hen Harriers Circus cyaneus to extinction in England." I believe that this would definitely be the case. The current laws are already ignored as it is by some.
Common Buzzard Buteo buteo
The paper makes no bones about its findings stating that: "By ignoring their population biology and interaction with other species, ad hoc local control of predators such as buzzards could just as likely exacerbate losses of pheasants as reduce them. In the future, effective game management interventions will require far more rigorous analysis of the ecological, conservation, and economic consequences of maintaining supernormal densities of introduced game species than has been achieved so far."
I'd like to bet that this will not happen. Money talks!

Common Buzzard Buteo buteo
The paper ends, as expected, with a comprehensive list of references but, it does not give a link to an online version and I only have a hard-copy.

Wednesday, February 6, 2013

A Birding Weekend in Norfolk

I spent the whole of last weekend birding in Norfolk trying to find wintering species and at the same time trying to keep as warm and dry as possible. On Friday morning I drove down to Thetford and met the rest of the guys in the car-park at Nunnery's. The first target bird was the long-staying Black-bellied Dipper Cinclus cinclus cinclus. This bird is an example of the nominate north European race with the black/brown underparts (as can be seen in the picture below). The mainland British race, gularis, has a strong chestnut area below the white breast. It was easy to find but not so easy to photograph as the light was really poor and, stupidly, I had not brought a tripod. So hand-held, 400mm lens whacked up to 1600 ISO and I could only manage 20th sec. Hence slightly blurry shots. Still, good views of the bird and a good start to the weekend's birding. Jay, Kingfisher and Marsh Tit also put in an appearance to add to the list.
Black-bellied Dipper Cinclus cinclus cinclus Thetford
A real bonus was a sighting of an Otter working its way down the bank of the river Little Ouse (I think!). It was more-or-less permanently underwater but by following the bubble trail it was possible to follow the beast underwater and plan ahead to take a picture when it momentarily broke the surface. Again the light was poor and so is the photograph.
Otter Lutra lutra on the Little Ouse in Thetford.
After Thetford it was off for a couple of hours walk around Lakenheath Fen RSPB reserve on the Suffolk-Norfolk border. A brief sighting of Bittern and a lone Whooper Swan were good to start with but we failed to see any Common Cranes. There were swift views of Bearded Tits, a couple of Stonechat and at least five Marsh Harriers hunting over the extensive reed beds. A powerful Peregrine Falcon belted along the river hoping to catch an unwary Teal or wader and so were we! But there weren't many waders to be seen apart from hundreds of Lapwing on the move - as were Fieldfare. After a good period of grubbing about at Lakenhath it was time for the mini pork-pies and then the drive to north Norfolk to our weekend's accommodation.
Whooper Swan Cygnus cygnus. The lone bird at Lakenheath
By the time we arrived at our digs it was getting dark so that was the cue to start worrying the wine that needed tackling before setting off to the local boozer for beers and food. Then it was back to do damage to the Talisker single malt!
The following morning saw a bitingly cold and strong wind with rain in the offing. But being as tough as commandos on a mission we were up and at it down at Titchwell RSPB reserve fairly early (After a leisurely full cooked breakfast, coffee, juice toast etc. - commando food) It was freezing and spitting with rain but we managed to rack-up a number of species including a female Red-crested Pochard, a good number of Brambling but unfortunately not a lot on the sea. Sea-watching was difficult as the sea was cutting-up and the wind was whistling in from the North-east blowing optics and people all over the place. It didn't seem to bother the birds though as this shot shows:
Oystercatcher  Haematopus ostralegus battling against the wind and waves at Titchwell
After Titchwell we drove down to the beach at Holme to search for a flock of approximately 80 Snow Buntings that had been reported from there. It didn't take long to locate these birds as they were very flighty and there were a lot of walkers about. We finished the day at Holkham trying to see Woodcock and Tawny Owl before heading back to the digs for more wine and more whisky.
Sunday and the wind was colder and stronger than yesterday and it was bloody freezing. Still being commandos we were out at Choseley drying barns early morning (after a leisurely full cooked breakfast, coffee, juice toast etc. - commando food). This was a good decision as we had great views of a Merlin as it came zipping through the fields and we passed a flock of at least 5 000 Pink-footed Geese searching for suitable feeding fields - a great spectacle as they flew over us in the early morning light. The hedges held good numbers of Yellowhammer and Brambling and there were a few Corn Buntings hanging about.
From Burnham Overy Staithe we walked the sea wall out to the dunes and saw virtually nothing apart from a couple of Common Scoter and a couple of Red-throated Diver out at sea. So we set off for Holkham Pines to look out from the Tower-hide for White-fronted Geese - duly found; Rough-legged Buzzard - not found and Barn Owl - found. There were at least seven Marsh Harriers competing for food over the marsh as well as three Common Buzzards, a Sparrowhawk, a couple of Kestrel and a Barn Owl. Who'd be at the bottom of the food chain?!
We twitched a Purple Sandpiper feeding in a pool in a field at Cley. Strange habitat for a Purple Sandpiper we thought but apparently feeding in freshwater pools by the sea is a well-known feeding strategy of these birds.
On the way back we had great views of a Barn Owl feeding by the side of the A149 and a number of cars had pulled over to enable the occupants photographic opportunities. So we joined them. Again poor lighting and poor photographic skills prevented me from securing some decent shots.
Barn Owl Tyto alba feeding by the side of the A149
We had to cut the birding short as the pub was was the Talisker and yet more wine. We popped into the supermarket at Wells for some milk and came out with three more bottles of wine...just in case.
Pink-footed Geese Anser brachyrhynchus - Part of a flock of at least 5 000 birds near Choseley
The tally for the weekend was 114 species which was not bad considering the iffy conditions. We had seen anumber of mammals too and quite a lot of dead things!