27/05/14 - Royal visitors to the LDV

Back in January 2013, three otter cubs were found over the course of a few days, and were soon in the care of Jean Thorpe MBE (Ryedale Wildlife Rehabilitation) - one of our long standing volunteers and key member of the LDV NNR Team. It is likely that these cubs had been orphaned with the females possibly run over on local roads as a result of the river levels being high. Otters don’t tend to swim under bridges for some reason – instead preferring to walk along ledges or the river bank. As the river levels come up this often submerges the banks or ledges forcing the otters to walk up and over the bridge, often bringing them into contact with vehicles and occasionally getting hit by them.

As usual, having assessed the situation and weighed up the options, Jean gave them emergency care in the short term before they were taken to The Chestnut Centre in Derbyshire before going on to their bigger centre, The New Forest Wildlife Park for rearing. They do an amazing job with the rehab of wild otters, which is a fairly long process as the cubs take about 18 months to mature before they would leave their mother naturally in the wild. One of the cubs unfortunately did not make it but the two males grew well.

Both these otter cubs had fur covered that was covered in white spots – a less frequently seen form than the more usually plain brown form – historically known as royal otters.

Around the same time another female cub came into care at Jean’s, from Skerne East Yorkshire, found alone on a cold and frosty night. She was soon revived but had an injury to her tail. Mike Jones from Battleflatts Vets, Stamford Bridge examined her and the tip of her tail had withered and she needed an operation to remove the dead tissue. Mike did a wonderful job and her tail healed well, she was then named Stumpy! She too travelled down to the New Forest and was superbly cared for.

Release plans were put in place and the three adults, Hover and Rye (the spotted royal otters) and Stumpy were to be brought back to the area once the time was right. Hover and Rye were to be released in the Lower Derwent Valley NNR as the site falls within the wider catchment in which they were found. The site also offers a safe, undisturbed and prime area of habitat in which they can settle in and find their feet in their early days in the wild. The timing is also important in that the floods around the valley have receded and there is plenty of available food (fish and amphibians) concentrated into the 90 km of ditches around the reserve. 

A small pen, made from electric fencing in an area of dense wetland vegetation and with a small pond, plenty of willow scrub to lay up under and room for their travelling boxes was made. The day of the release came, and what a glorious one it was, a Wheatear bounced along the river bank fence posts as we headed to the site, and the sounds of displaying Lapwing, Curlew and Redshank overhead could be heard with the constant back ground accompaniment of Skylarks. Loafing drake Mallards, Gadwall and Shoveler were present along the riverbank and ditch sides suggesting the females were incubating clutches nearby, and vast numbers of tadpoles and shoals of fish were present in some of the ponds – what better place to start the rest of their free and wild lives. Hover & Rye were clearly ready to be back in this environment and didn’t hang around for long, not needing to take advantage of the free food hand outs over the next few days – a great result.

Stumpy was taken to her release site in East Yorkshire with our partners at the Yorkshire Wildlife Trust where she was quietly placed in the pen, she was more reserved than the males and didn't come out into the open instantly like Hover & Rye. Her release went well and she now too has gone out into wonderful otter habitat away from roads and people.

Whilst the release was a truly wonderful experience to be involved with, it was just the final hours of a long 18 month journey which included a whole host of people, starting with the concerned householders of Fryton, Slingsby and Skerne who first found and reported them, Ed Heap, Roger Heap, Jason and Donna and all the staff at the Chestnut Centre and New Forest Wildlife Park for their wonderful care of these orphans, Mike Jones, the vet for his support and care for wild animals, Jon Trail at the YWT and all the staff and volunteers at the Lower Derwent Valley NNR. But most importantly, Jean Thorpe for her excellent care and dedication as always, and for coordinating the whole process.

01/05/14 - Whimbrel'ing on Wheldrake

On Tuesday staff and volunteers from the LDV Team spent the night on Wheldrake Ings catching Whimbrel – and with 109 birds coming into roost the previous night things were looking good. The nets were positioned in three different areas which we believed the birds may pass through on route in to the roost. At 2010hrs the first birds, a group of four, flew into Swantail Ings and by 2050hrs a total of 58 were present. A final flock of 51 (which had roosted and come in as a single flock the previous night) flew in around 2100hrs, another hour’s wait for complete darkness then we could start doing the rounds. Over the course of the evening and into the early hours many miles (or what felt like!) were walked in chest waders, through deep water, thick mud and long vegetation but it was all worth it for a catch of 8 Whimbrel, 1 Lapwing and 1 Mallard.

One of the newly c/r Whimbrel for 2014

 

Out of the 8 Whimbrel 6 were new with 2 from previous years – one from 2009 and one from 2010. With the difficulty of reading colour-rings in the field this year it was most pleasing to catch these two birds. Full details are listed below:

EL49894: Yellow//Green Yellow 

2009 - Ringed on 29^th April at the Wheldrake roost

2010 - Re-caught at the Wheldrake roost on 26^th April

2012 - Sighted on 4^th May at Nosterfield Gravel Pits, North Yorkshire

2013 - Re-sighted on 22^nd April at the favoured feeding fields in Storwood

2014 - Re-caught at the Wheldrake roost on the 29^th April

EL49985: 

2010 - Ringed on 2^nd May at the Wheldrake roost

2014 - Re-caught at the Wheldrake roost on 29^th April

Since the initial ringing date the oldest bird here (EL49894) ringed in 2009 has travelled at least 80,000 Km on its many journeys between the Lower Derwent Valley to Iceland (to the breeding grounds between May to August) and then on to the West African wintering grounds from September to March before returning once again in the spring to the Wheldrake roost.

As mentioned previously we’ve struggled so far this year to read colour-rings from birds in the field during the day, which over the years is how we’ve managed to build up such a great set of data – with to date over 195 sightings of 53 colour-ringed Whimbrel (out of 106 which is the total number of birds colour-ringed since the start of the project in 2004).

Interestingly this year we also haven’t seen the birds as frequently in their favoured feeding fields – which is presumably down to the fact that the fields are so dry (and with a good growing season, the vegetation is too long to favour them) so they seem to be struggling to feed and find available earthworms and leather jackets (cranefly larve) - their favoured food. In fact the only feeding birds found this year have been unusually found on newly ploughed fields which have presumably offered them an easy, but temporary feeding opportunity. This was then confirmed at the roost as out of the 8 birds that were caught the weights ranged from 385 being the lightest with 425 being the heaviest. The average weight/what we would expect at this time of year and at this stage in the valley is around 450 to 500 grams so about 100 grams down on what might be expected. Whilst that doesn’t sound like much it is about 15-20% of their body weight. These individual birds are likely to only be here for another 8 days or so, and during this time they feed up on their main prey items of worms and cranefly larve, almost doubling their body weight before setting off on their 24 hour non-stop journey to Iceland, and with such a long journey before them it’s so important that they manage to feed up during their short stay in the valley.

During the evening of the roost we were treated to views of Greenshank and Little Ringed Plover, along with listening to Snipe drumming. Whilst walking the fields we also came across three clutches of Lapwing eggs (all of 4 eggs) and a Coot incubating 13 eggs. A late passage Jack Snipe was seen twice, a Roe Deer was heard barking on several occasions and a male Barn Owl was quartering over the site during the evening.

29/04/14 - A good haul

Following on from our post a couple of weeks ago regarding the local heronry we returned last week to ring the chicks, knowing that they should be the right size by now – and before they become too big. We were successful with 29 chicks ringed from 10 nests with young – many others nests still had eggs. The broods varied in number (from two to five, with three being the average) and in size – with the biggest and smallest photographed below. Each chick was fitted with one of our yellow darvics with two black numbers. Once the chicks fledge they tend to appear on Wheldrake with it being the nearest water body, before leaving the area and heading north, and hopefully with 29 newly darvic'd birds soon to be out there we've a good chance of getting a return back. For more information on our herons, and where they go and what we've found out so far see last weeks post here.

Many thanks to the tree climbers at Lewis Trees for their once again excellent service with scaling the trees quickly and safely and in their safe handling of the birds.

 

13/04/14 - Climbing high

Last week we paid the first visit of the year to the local heronry to ascertain how the breeding season was going so far. A good number of adults were present, and many empty egg shells were located beneath the trees. Calls of young birds could be heard and so the spikes were donned ready to scale the dizzy heights of the larch and pine trees, however upon reaching the top most of the young were newly hatched with just one bird being of a ring-able size. This isn’t what we were expecting to find compared with previous years, with the milder spring and higher temperatures a number of species started breeding earlier than last year and so we were expecting the chicks to be much further on. Herons are one of the species known to be early nesters with some records as early as February for birds on eggs, however March is the usual time for herons to start laying with the incubation period c27 days. We shall now return in c10-12 days to hopefully ring and darvic a number of the young.

Herons have bred in the heronry here for at least 40 years, along with Little Egrets in 2010, which went on to produce two young. These two species are known to nest alongside each other, however the latter is a much later breeder. Herons are rather sociable birds, breeding in close quarters, a single tree has been known to hold as many as 10 nests! Herons are known for nesting in long established heronries with data going back as far as 1928 when the first survey by the BTO took place, since then heronries have grown in number with the biggest heronry being on an RSPB reserve in Kent with over 150 nests, down from 200 in previous years.

Last year we managed to ring and darvic 22 birds over the course of four days throughout April and May, with the first visit being on the 16^th April and the last being on the 17^th May. Out of the 22 birds ringed last year we’ve had two sightings, which is much in line with the national reporting rate of 11%. The first bird was seen briefly locally however the second was seen at Nosterfield Nature Reserve, nr Ripon on the 16^th August, three months after being ringed in our heronry.

From the ringing recoveries that we’ve collected over the years in the valley we’ve found out that our young herons undergo a rapid post breeding dispersal to the north, with recoveries 50-60km north of the LDV by July/August. Given that heron numbers also peak in the valley at this time would suggest that these birds include at least some that have dispersed from other sites presumably further south, and are not just the local breeding population as previously thought. 

Foreign recoveries from birds ringed in Britain only make up 3% of the total with the most being in France, and prior to 1940 the proportion of recoveries in foreign countries has declined from 12% to 2% in the 1990’s but the reasons remain unknown as to why. Despite herons being relatively common and widespread there are gaps in our knowledge of heron movements, including the movement during the year of adult birds and the apparent population shift towards coastal areas in the winter as suggested by counts. The national data does however suggest that general dispersal movements occur over the first five months of life, later returning to the natal site to breed, which fits with what we suspected was happening in the valley.

27/03/14 - From Wheldrake to West Africa

Long term followers may remember that in its early days this blog was largely focused on the ringing projects and activities in and around the Lower Derwent Valley NNR, as a way of sharing our experiences and results with other ringers and interested individuals elsewhere in the country. Since then the blog has covered a wider range of activities undertaken by the team (staff and volunteers) here at the Lower Derwent Valley and other NNR’s in North Yorkshire, but our ringing activities have continued throughout, albeit at times restricted due to flooding and seemingly endless weeks of unfavourable weather conditions.

The reason we ring birds is for the purpose of gathering data and in waiting to hear about recoveries and controls of the birds we have ringed which can provide us with insights on dispersal, migration routes and longevity. Some of these recoveries have featured on the blog during the last year such as our elderly Tawny Owl and our first dispersing Grey Heron chick.

Here are some recent and some not so recent recoveries we’ve received concerning birds ringed or recaptured in the Lower Derwent Valley NNR.

Whimbrel

We’ve recently received a few more sightings of our colour-ringed Whimbrel from the long term study at the nationally important Wheldrake Ings spring staging site in the Lower Derwent Valley. Once again it shows the importance and use of colour-rings in helping to gather data which otherwise wouldn’t have been possible to get. 

A bird that was ringed at the Wheldrake roost back in 2008 was seen in Normandy, France in May last year, full details below:

Whimbrel (EL99843): Red/Lime Red

2008 - Ringed on the 1st May, seen several times afterwards until the 6th May

2010 - Seen back in the LDV on the 22nd April (DT)

2011 - Seen back in the LDV on the 20th April (PR), present until at least the 24th April (PR)

2013 - Seen in a roost at Manche, Normandy, France on the 3rd May 

We’ve also had one seen on return migration following the breeding season, with a single bird seen in two consecutive autumns on the Ythan Estuary in Aberdeenshire.

Whimbrel (EL45771)
 

2005 - Ringed at Wheldrake Ings on the 2nd May

2006 - Seen back in the LDV on the 3rd May

2010 - Seen at the Ythan Estuary, Aberdeenshire

2011 - Seen at the Ythan Estuary, Aberdeenshire 

More recently Dutch researchers working in Guinea Bissau in West Africa photographed two colour-ringed Whimbrel wintering over there. One of them was one of our birds originally ringed at the Wheldrake roost in 2008, full details below.

Whimbrel (EL49639)

2008 - Ringed at the Wheldrake roost on the 25th April

2009 - Seen back in the LDV on the 24th April

2011 - Seen back in the LDV on the 25th April

2013 - Seen back in the LDV on the 22nd April

2014 - Seen in Ilha da Ponta, Bijagos, Archipelago, Guinea Bissau on the 14th January

Seen by Dutch ornithologist, Pete de Boer, this bird was one of 48 roosting on a beach at high tide. Another bird in the flock also had colour-rings, this individual had been ringed as one of the small British breeding population on Shetland.

 

c/r Whimbrel on the beach in West Africa 

We’re now looking forward to the birds heading back to the valley this year – only three weeks or so to go before the first birds arrive at Wheldrake Ings on their way back to the Icelandic or Scandinavian breeding grounds. We’ll be out and about looking for them arriving back, counting the evening roost and searching for the day time feeding fields and checking for our ‘old friends’ coming back.

Shelduck 

Last month we received news that one of our darvic'd Shelducks had been seen at Martin Mere, a bird initially ringed in the valley in 2012, details below.

Shelduck (GR42655 - HJ)

2012 - Ringed as a 7F on the 15th February at North Duffield Carrs

2012 - Re caught on the 15th March at Thorganby

2013 - Seen at Martin Mere WWT reserve on the 11th January 

Shelduck fitted with a darvic ring 'TX'

This is now the fourth LDV Shelduck to go to Martin Mere whilst a single bird ringed there has also been seen here. Fitting our Shelduck with the black and white darvic rings pictured above has produced numerous sightings since the project first began back in 2002, with a total of 300 birds caught and darvic'd during that time. The sightings have largely been UK based, with the furthest recovery on record being of a bird ringed in 2004 at North Duffield Carrs, which made its way to Germany several months later. The most recent recovery out of the country is a bird that was ringed in 2007, and was then seen in Dublin Bay, Northern Ireland, 381 Km from its original ringing location. 

Shoveler 

Each summer we try to put a lot of time and effort into catching ducklings, so that we can try and find out more about how far our British bred ducklings go and how quickly they disperse. Recently we received details of a Shoveler duckling that was ringed in 2006 and later shot dead in France in 2013, full details below.

Shoveler (FP59233)

2006 - Ringed as a pullus on the 25th June at Wheldrake Ings
2013 - Shot on the 10th November in Saint-Pere-en-Retz, Loire-Atlantique, France, 747 Km to the south.

This is the seventh recovery of a Shoveler duckling ringed in the LDV, with four previous birds shot in France during the autumn/winter (August-January). At seven years and five months it also represents the oldest bird recovered so far.

 

Shoveler ducklings - Wheldrake Ings