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Where are we at?
Q: Are any of the released birds breeding yet?
A: Cranes rarely breed before they are 4 years old, so we were amazed that two separate pairs built nests in the Spring of 2013. Although both went on to incubate eggs, neither pair were successful.
Spring 2014 saw five pairs hold territories in Somerset, with 2 pairs going on to lay and incubate eggs. Sadly both these pairs failed, with the eggs taken - presumably by ground predators. In the same year two pairs at the Slimbridge Reserve bred with Monty & Chris successfully hatching 2 chicks in late May. Sadly both chicks were lost - one at 5 days and the other at 20 days. The second pair (Bart & Ruby) didn't hatch their eggs, and one was found to be addled, and the other dead inside the shell.
2015 has seen an incredible 16 pairs form and hold territories, many in the Somerset Levels and Moors, but others in South Wales, Wiltshire, Gloucestershire, Oxfordshire and East Somerset. Nine of these pairs are known to have made breeding attempts (build nests /incubate eggs) with 4 of these going on to hatch and raise chicks – ie 44% of the breeding pairs. Three of these four pairs have gone on to raise a chick or chicks to fledging - Alexander (a 2012 male) & Swampy (a 2011 female) on Kingsmoor in Somerset; Minnie (a 2010 male) and Wendy (a 2010 female) on the WWT Reserve at Slimbridge; and Midnight (a 2012 male) and Gemma (a 2010 female) on private land in Wiltshire. These are the first pairs of released birds to successfully raise young to fledging - and we hope - the first of many!
These are excellent results, particularly when you consider that many of these are first time pairs, with no experience, and they are learning all the time. We have already seen an upward trend in success of pairs that have made attempts in previous years –eg they may just incubate for a few days in the their first year before losing their eggs, the next year, they incubate for longer, or get the eggs to hatch, but lose their chicks.
The project aims to establish around 20 breeding pairs in the South West by 2025.
Q: How many eggs were collected for the reintroduction?
A. The project aimed to collect 24 eggs each year for five years. Over the five years 2010-2104 we have transported 121 eggs back to the UK, 114 of which hatched. From these 115 chicks - 93 have been reared to release, with 3 being held back in captivity for welfare reasons.
Q: Has this had any effect on the German population?
A: It would appear not. Our Germany partners have been very diligently monitoring the pairs of cranes from which we take the eggs, and there appears to be no statistically significant difference in fledging success of pairs from which we take eggs, and pairs from which we don’t.
In other words the birds re-lay once we have removed the eggs, and these new eggs go on to hatch and fledge with the same % of success as other pairs in the same study area where we don’t take the eggs.
Q: How many birds did you release on the Levels and Moors?
A: We have released 93 birds in total. 21 in 2010, 17 in 2011, 19 in 2012, 19 in 2013, and 17 in 2014 - one of which was taken back into captivity to leave 92.
Q: How many of the released birds survive?
A: 75 of the released birds are currently known to be alive. This represents an 81.5% survival rate. The project had a target of 60% survival to adulthood as this is the usual survival rate for birds across their range in continental Europe. However, the birds don’t reach adulthood until their 3rd year and there are a number of tricky life-stages to come – such as their first moult, where they become flightless for a period of around five weeks – see below.
Q: What happened to those that didn’t survive and have you any missing birds?
A: Two birds of the first cohort died during their first Autumn. A bird known as Jack flew into powerlines and was killed, and a bird known as Howard disappeared in the autumn, and its remains were found much later, with the cause of death not clear. A third bird, Dennis, from the 2010 cohort was taken back into captivity for his own welfare and is currently within the Pensthorpe Conservation Trust collection. The following autumn, on the release of the 2011 cohort a bird known as Mildred flew off, was seen in Kent and then disappeared. It has not been seen since and we don’t know if it is alive or dead. Another bird from the 2011 cohort, Gizmo, became ill over its first winter, was alone and isolated from the group, and was taken by a fox in the night. In 2012 a birds known as D2 sustained a fairly severe leg injury, but proved uncatchable for treatment. It became a bit of a loner, and was probably pretty under the weather, when it was finally taken by a fox in March 2013. Trinny from the 2011 cohort went missing in April 2013 - but in the company of an unringed cranes - so perhaps is elsewhere in the UK or abroad. Vince from the 2010 cohort went missing in May 2013 around the time of the start of moult. Her whereabouts or life status are unknown. Clarence also from the 2010 cohort started behaving oddly in spring 2013, hanging around on his own a lot - which usually indicates that a bird is ill. We saw him go into moult in June, however, and are pretty confident he was seen in flight following moult in July - but he has subsequently disappeared and his life status is also unknown. The radio tag and a few scraps of feathers and bones of Jess from the 2012 cohort were found in early September 2013 - her cause of death is unknown. Jess had always been quite a weak bird, and a poor flier - but had seemd to be been doing well. The remains of White Green Yellow, who was one of the newest batch of birds, released in August 2013, were found out on the moors on 1st November 2013. His cause of death is unknown, but his remains had been scavanged by a predator, most likely a fox. Charlie - one of the 2011 cohort, went missing in late October 2013, and has not been seen to date and Frieden - one of the 2013 release cohort disappeared during the winter of 2013/14 and has also not been seen since. Pepper - one of the 2011 Cohort was last seen in December 2013. Sven - from the the 2013 cohort had a collision with a powerline in February 2014, and was found, recovered and taken for treatment, but had to be put-down on account of a severely broken wing. Misty Moor, from the 2013 cohort was last seen in May 2014 and his whereabouts are unknown, and two of the 2014 cohort Humbug and Yellow Red Black were found dead in early November 2014. Cause of death of these two were likely to be linked to leg injuries that they sustained shortly before being found dead, although the cause of the initial injury, and cause of death is unknown.
Q: So with many of the birds now over 3 years old... they must have had their first moult?
A: Yes – most of the 2010 release year birds underwent their first full wing-feather moult in June/July 2013. They found very quiet areas down on the moors where they were undisturbed and could roost in safety. It was a tense time for us all - but it would appear that they all made it through safely - although one 2010 bird (Vince - see above) disappeared shortly before and one (Clarence) shortly after the moulting period. 5 of the 2010 cohort did not moult in 2013. Most of the 2011 birds moulted in the summer of 2014 and all have been seen again. We expect that most of the 2012 cohort will moult this coming summer. (2015)
Q: Are all the birds in Somerset still?
A: No and Yes! A handful of birds moved further north and appeared to have made a home in the Wetlands of the Severn Vale and could often be seen feeding on the WWT Slimbridge reserve. However in early September 2013 these five birds came back to Somerset. In late October 2013, 12 from the group headed back north again leaving 54 in Somerset, with 6 of these returning in November to leave a flock of 60 in Somerset, and 6 in Gloucestershire. In the spring of 2014 there was a lot more movement - but finally 7 birds settled at Slimbridge (Three pairs and a 'spare' female) where they remained, being joined by 2 more from Somerset in November 2014 to make 9 - 4 four pairs and 'spare' female. There have been other movements of birds between the two areas and the picture is complicated and often confusing! The birds certainly don’t seem to find it any effort to move between the sites – with the biggest movements usually coinciding with periods of high pressure and good thermals. Ringed, released birds from the project which have ended up back in Somerset - have also been seen on occasions as far north as Staffordshire, as far west as Glamorgan, Wales, as far South as Devon and incredibly as far east as Suffolk! More information on the movements can be found in the annual reports.
Q: Have they mixed with other resident cranes from the wider East Anglian population?
A: An unringed crane turned up in the autumn of 2011 and stayed with the flock in Somerset over the winter. This bird then left the flock in the Spring of 2011 – at the same time as one of the ringed birds turned up in Suffolk. The origin of this bird is unknown – but it could well have been from the UK population rather than from the continent – and may have led the ringed bird to Suffolk. An unringed crane (Miss Wild Naked Legs) appeared with the birds at WWT Slimbridge in autumn 2013, and then moved to Somerset for the winter of 2013/14. The origins of this birds are unknown. It is inevitable that, in time the birds released through the project will come into contact with cranes already here in the UK. We hope that the two populations will eventually mix and the project’s aim of helping to secure the long-term future of the crane in the UK will be realised. Another (or possibly the same?) unringed crane turned up with the Somerset flock in Spring 2014 and has remained with them ever since.
Q: What about the habitat aims of the project – how is all that going?
A: Very well! Along with the release of the birds the project has been working to create new suitable crane breeding habitat across the Levels and Moors so that the project can achieve its target of 20 breeding pairs by 2025. Currently works have been carried out the RSPB’s own landholding at West Sedgemoor and Greylake, and on private land on Aller Moor to the West of Langport, Walton Moor near Street, Northmoor near Aller, Cossington Moor, Kings Sedgemoor near Henley, and Moorlinch Moor to the North of the RSPB's Greylake Reserve. Sites on the Somerset Levels and Moors that are managed by the Somerset Wildlife Trust and Natural England at Catcott Lows and Shapwick Heath are now being managed with cranes in mind too.
Last updated - September 2015
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