Thursday, 31 December 2015

A ton of gold...

Last night, Silvia and I headed out for our last lamping session of 2015. The weather was by no means perfect for catching, but the moon wasn't up until 22:00 so it was pretty dark. Although all of the rain meant that the fields were great for waders to feed on them, it also meant that creeping up on them was very difficult. Unfortunately the Snipe could here me from a long way away, and as a result I didn't catch any. Thankfully there were a few 'dry' patches where being quiet wasn't as tricky. On one of these patches I spotted a single Golden Plover. Somehow I managed to creep up to it and catch it. Amazingly this is the 100th new Golden Plover I've caught this winter! Although it's been a very mild winter, numbers of Golden Plover on our ringing sites have now dropped to single figures. Early on in the season there were 100+ in some fields, this drop in numbers has also been reflected in the number of birds caught - 3 in September, 48 in October, 35 in November and just 14 in December. Hopefully some of the birds will get re-sighted so we can learn more about their winter dispersal.

Two other milestones were also reached last night when I caught mine and Silvia's 100th Fieldfare of the winter. and in doing so also brought up our 500th 'dazzled' bird of the winter. Hopefully January to early April can also bring us some more good catches.

Roll on 2016!!

Monday, 28 December 2015

Dippers rising!

Just before Christmas, battling the after-effects of my first dose of man-flu for over two-years,  I plunged into the flooded waters of the Rivers Wye and Irfon in order to check a few more roost-sites of Dippers (not a wise move on your own really as I ended up soaked to the skin and almost got swept away!).

Earlier this year we ringed 535 nestling Dippers, an all time high, and checking all known roost sites in the autumn/winter is a great way of finding out how well these birds have survived and where they have subsequently settled following their post-juvenile dispersal. It also allows us to colour-ring the survivors as we don't colour-ring chicks in the nest due to the naturally low survival rate. 

Spray-covered Dipper roosting on a rock-face near a waterfall. Nearby (and impossible to photograph unfortunately) was a bird roosting behind a raging torrent!

So far this season we have checked 257 roost sites and recorded 342 roosting Dippers of which 301 have been caught or identified from colour-rings. Well over 50% of all birds caught were retraps or controls. Dippers are pretty sedentary but females especially will swop river catchments. The furthest movement recorded so far this year is of a nestling that I ringed on the River Rea near Neen Savage in Shropshire and then re-rapped on the upper reaches of the River Teme, a straight-line distance of over 53 km. 

The Dipper equivalent of a Sandwich Tern in Namibia!

Roost counts at occupied roosts were  as follows:-

1 x 12
2 x 9
2 x 7
4 x 6
5 x 5
15 x 4
22 x 3
34 x 2
55 x 1

The remaining 117 suitable or previously used roost sites had no birds present. We still have about 50 odd known sites to check if/when the waters subside.

It is clear from this monitoring that the Dipper population locally is continuing to recover from a population dip in the  1990's almost certainly caused by the use of new powerful Synthetic Pyrethroid (Cypermethrin) sheep-dips (withdrawn from sale in the UK in 2010) and undoubtedly helped by the provision of well over 100 purpose-built nest-boxes.)

Saturday, 26 December 2015

An amazing Christmas Sandwich!

What's the best present you can give a bird-ringer for Christmas? Well you could do a lot worse than a Christmas Sandwich! 

A few years ago we started colour-ringing Sandwich Terns at Ynyslas National Nature Reserve in order to study the annual autumn passage of these amazing birds through the site. In 2013 we caught 83 different Sandwich Terns but were only using BTO metal rings at the time. Few recoveries of these birds have been received so far but as Sandwich Terns are long-lived some may yet arrive. Following our success in 2012 we registered a colour-ringing scheme in 2013. As is often the way, the autumn passage was considerably smaller in 2013 and 2014, with unfavourable weather conditions at crucial times, and we only managed to ring 11 birds in 2013 and just 2 in 2014. In 2015, after another unpromising start, things improved and we colour-ringed 43 birds, including 4 retraps/controls of birds ringed in earlier years/elsewhere. We have already had a number of sightings of these birds in Southern England on their onward journey and some from breeding colonies in the North-East of England. 

Late on Christmas Eve I received an email forwarded by Ewan Weston, who co-ordinates sightings of colour-ringed Sandwich Terns in the UK, from Mark Boorman who had recently read the ring of one of these terns at Walvis Bay Oyster Beds in Namibia!! Certainly brightened a wet winter evening and absolutely amazing to know exactly where one of these birds is spending their winter, amongst the Pelicans and Flamingos on the Skeleton Coast on the edge of the Namib desert - it's certainly no turkey!

Sunday, 20 December 2015

Christmas wrapping

At a time of year when people marvel at the beauty of the Barn Owl, because they inevitably will have a Christmas card with one on, I have been busy wrapping my latest Christmas box.

Lee Walker, from the Predatory Bird Monitoring Scheme contacted me last year asking for any dead Barn Owls to be forwarded on to him, regardless of how they were killed. They send out the freepost boxes, I usually have one at home so that I can send it off quickly before the birds start decomposing. They aim to quantify any levels of contaminants in the liver and eggs of selected species, to determine how and why they vary between species and regions, how they change over time and the effects they have on individual birds and their populations.
This is the 3rd Barn Owl I have had from this general location in as many months, no wonder that is our worst performing area!

Posted on behalf of Chris Griffiths, Montgomeryshire Barn Owl Group

Monday, 14 December 2015

A pair of Shorties (or what exactly do Short-eared Owls eat?)

The past couple of nights have seen a bit of very successful lamping, both inland and on the coast. On Friday Jacques and I headed up to the Ceri Ridgeway to try and ring a few more Golden Plover. Halfway across the first field I spot a double eye-shine in the beam (this is unusual as with waders you almost always get just one). Initially I thought it might have been a polecat but as I got closer I could make out the unmistakable shape of a Short-eared Owl. Now walking a bit more carefully,  I edged forward until I was close enough to drop the net on it. Only then could I see that, even whilst under the net, it was still holding on tightly to a decapitated Fieldfare it had partially plucked and eaten. Jacques seemed pretty pleased and got to ring his 101 species as a trainee, which isn't bad going in just over 7 months!!. The rest of the fields yielded 5 Woodcock, 7 Golden Plover, 2 Fieldfares (with heads) and a Snipe. We also watched the same or another Shorty in hot pursuit of a Golden Plover that had just flushed in the beam!

This bird was aged as a first-year female based on tail pattern and the
 buff background colour and barring on the outer secondaries. 

The following evening Jane joined us and we headed down to Ynyslas to see what waders we could catch on the high tide. There were a good number of Redshank present and we quickly caught 23 (and could have easily caught another 10) before realising that I only had 22 'D2' rings on me! Was a bit traumatised to have to release one without a ring!

Having run out of rings for Redshank we decide to have a quick walk around the fields for Woodcock, Snipe and Jack Snipe. Halfway around the usual beat, having failed to get anywhere near any of the 20+ Snipe flushed, I get a double eyeshine in the beam again. As I get closer I can see it is another Short-eared Owl! Only one problem, there's a great big pool of water between me and it. Go round or keep it in the beam and go straight across? I opt for the latter and walk as quietly as I can through the middle of the pool. Thankfully, the owl sits tight and is soon under the net and I can then see why it was reluctant to fly off - it was sitting on the half-eaten remains of a freshly killed Lapwing!

This bird was also aged and sexed as a first-year female although on seeing these photos I'm beginning to doubt the sexing of the first bird? It could just be the different lighting but it appears to be much paler than this one. Advise from anyone with more  experience of the species is very welcome!

Over the past few winters we have caught (or narrowly missed) several Shorties whilst they were on freshly caught prey items - Lapwing (2), Redshank, Knot and Fieldfare. I'm staggered at the size of prey they will tackle - Short-eared Owls weigh around 300g whereas a Lapwing weighs about 250g and a Redshank about 150g so that's a half to well over two-thirds their own body weight! They are clearly fearsome predators of waders and surprisingly nocturnal too!

PS Since this post went live some concern has been expressed to BTO by another ringer that these owls may have been near starvation and that is why they were reluctant to fly off! By way of reassurance I can confirm that both these owls were perfectly fit and healthy and weighed 309g and 335g respectively - well within normal limits. TC.