Migration update and satellite tracking news

Late August and early September always bring mixed emotions for anyone involved in the project. On the one hand it is exciting to see this year’s juveniles growing in confidence on the wing and then setting out on their first migration to West Africa, but on the other it is sad to be waving goodbye to the birds that we have been watching every day since late March. All manner of hazards lie in wait for the Ospreys as they head south; the open ocean of the Bay of Biscay, the guns of hunters and the vast wilds of the Sahara. Whilst the adult birds know where they’re going – our satellite tracking and ringing studies show that they return to the same wintering site each year – for the juveniles it is a journey into the unknown. Some will make it, but the sad reality is that as many as 70% of this year’s chicks won’t ever return. Much depends on the weather on their first migration. Strong easterly winds as they head south may blow the youngsters off course and into the sea; so whenever I look at the weather forecast for France at this time of year, I hope to see either southerly or westerly winds. To survive, the juveniles need a bit of luck – and good weather – on their side.

So which of this year’s contingent have already set off? If you’ve been watching the webcam you’ll know that of the three juveniles, only 3J remains. 1J and 2J are already winging their way south, and may well be in France or Spain already. 3J seems altogether more reluctant to leave. She’s spent much of the past few days either on or very close to the nest, food-begging incessantly. Whilst this is probably very irritating for her parents – who are both still present – it is actually an excellent survival tactic. By remaining in Rutland for longer than her siblings 3J will almost certainly be in better shape when she eventually sets off. Of course she still needs the weather to be on her side, but she has given herself the best possible chance by remaining with her parents – and the constant supply of fish – for longer. Here’s a video of 3J on the nest yesterday morning.

It’s a different story at Site B. As we have come to expect, the adult female left early; heading south on 8th August.  In her absence 03(97), who has now raised a total of 30 chicks, remained at the nest, providing several fish each day for his demanding offspring. Then, one by one, they set-off. By Monday evening this week just 03 and 6J remained. Unlike some males, 03 doesn’t always wait for the last of his brood to leave before he himself sets out on migration; and that proved to be the case again this year. When Tuesday dawned warm and sunny our most-successful breeding Osprey departed on his 16th autumn migration. Next day, 6J followed suit.

Site N is now devoid of Ospreys too. All of the family were present on Saturday morning, but once the weather improved on Sunday and Monday the two juveniles and their mother, 5N(04), took the opportunity to head south. As our migration studies have shown, Ospreys always migrate alone but it was interesting that the three birds departed in such a short period of time. Having seen his family off, 01(09) wasted little in following suit, setting out on the long flight south sometime on Tuesday.

We have much sadder news to report from Site O. On 12th August we revived a call from a local gamekeeper who said he had found an injured Osprey. Sadly when John Wright arrived at the scene he found that 9J – one of the juveniles from Site O – had flown into an overhead power line and had a damaged right wing. We took the bird to Oakham Veterinary Hospital, where we found that the wing was so badly broken that the bird needed to be put down. As the vets pointed out there was simply no way the injury would have  healed in time for the bird to make the long and arduous journey to the wintering grounds. 9J’s untimely death highlights the dangers of overhead power lines to young and inexperienced birds. Bird markers can help reduce the risk and we have since been in touch with the electricity company requesting that markers are erected on this particular section of cable. We will continue to follow this up and update you in due course. The remaining two juveniled at Site O – 7J and 8J – kept out of trouble and, along with their father, 03(09), they have now set out on migration, leaving their mother alone at the nest.

Sadly 9J's broken right wing meant that the bird had to be put down

Sadly 9J’s broken right wing meant that the bird had to be put down

The only other breeding Osprey that has definitely left Rutland is 25(10). Having raised three healthy chicks at Site C, she departed at the end of last week; leaving her mate 11(10) to provide fish for the youngsters. Having fledged later than their compatriots at the other nests, we are expecting the Site C juveniles to remain in Rutland until early September at least. It is worrying, therefore, that one of the females has been absent for a week. Let’s hope that she hasn’t suffered the same fate as 9J and, instead, has set out on migration earlier than expected.

Of course we can estimate how far the various birds have traveled on their migration thus far, but we’ll know far more about one particular Rutland Osprey this autumn. A couple of month ago we fitted a satellite transmitter to 30(05), an eight year-old female who raised eight chicks at Site K with 08(01) between 2009 and 2012. Sadly 08(01) failed to return to Site K this spring and 30 did not pair up with another male in time to breed. Instead she has spent the summer wandering around the Rutland area; visiting the various active nest sites, including Manton Bay. Here’s a video of her intruding at the Manton Bay nest earlier this spring.

Fitting 30(05) with a transmitter has allowed us to study her movements in incredible detail and, in doing so, highlight new areas that could be important as the Rutland population begins to expand. The satellite transmitter means that we’ll also be able to follow her journey to the wintering grounds this autumn. We’ll be posting daily updates on her migration once she leaves Rutland – which could be any day now.

Despite the recent news about 9J, 2013 remains the most successful year yet for the Rutland Osprey Project. 76 young Ospreys have now fledged from nests in the Rutland Water area since 2001 and 03(97) – or Mr Rutland as he is now better known – has become a great-grandfather for the first time. It is another real sign of success for the project and means that this year the inevitable sadness we feel about the birds departure is tinged with a great deal of satisfaction about a superb summer. We wish the birds well on their journey.

An-Osprey-migrating-over-Spain-one-of-the-best-places-to-watch-bird-migration-in-Europe

3 responses to “Migration update and satellite tracking news”

  1. Sally Bell

    Such emotions. Here’s to 2014.

  2. Mike Simmonds

    Tim, Thank you for a comprehensive if sad update. All we can do now is watch and wait once more. I sense in your post about the power lines a typical and total determination to sort out an issue which presents a hazard to ‘your’ birds. My regards to all the team. Mike S.

  3. Rosie Shields

    Tom. Thank you for the comprehensive update – with such a successful year, it is hard to keep track of all the combs and goings. So sorry to hear about 9J but glad to hear a story of a gamekeeper doing something positive for birds of prey; we often only hear when they have done something bad! Hopefully, 9J had not been there long and had not suffered too much before he found her.