Frequently-asked questions

There's still a lot we don't know about what young ospreys do on their migration, it's a hazardous first journey and stop-over sites, where they stop to feed up en route, are important to identify and recommend for protection if they are not already conservation sites.

Then, how do they spend the first years of their life in Africa, and when do they start coming north again? Being able to track the birds' journeys will add to our knowledge and understanding of the ospreys' lives and can help inform future conservation work.

We're really excited about sharing this knowledge with osprey fans around the world. We know that thousands of people have enjoyed watching the young birds growing up, so we're sure that you'll be fascinated by what happens to them after they've left Strathspey.

The youngsters will be fitted with small, solar-powered satellite tags that will transmit information about their journey. Initially, every hour – as long as the battery is charged up – the tag will send send the exact position (within 20 metres) on the Earth, as well as details of direction, speed of flight and altitude via the Global Positioning System (GPS) to our computer system. That way, we can build a very detailed picture of each bird's migration route.

Roy Dennis has been studying birds of prey, particularly ospreys, for many years and fitted the satellite tags to Nethy and Deshar.

He says: 'I, and colleagues from abroad, have no evidence that the transmitters cause navigation errors. The tag transmits infrequently and only at certain periods. In good or average weather, the tracks of both adults and young show them migrating without any evidence that the transmitters are affecting their navigation.

'Ospreys, like other migrating birds, sometimes get lost or die when they run into storms and bad weather, especially in heavy rain and thick overcast. Then, whether they have a tag or not, they usually fly downwind and hope to make landfall, feed up and restart their migration; lucky ones even survive major storms.

'The transmitters show that migration can be very difficult, and also the range of difficulties that some migrant ospreys, usually juveniles, have to endure and how many fail to make it to Africa.'

The tag weighs just 30 grams, just 1.6 per cent of the chick's body weight. Thanks to bird of prey expert Roy Dennis's previous work, we know that ospreys can carry them without problems on thousands of miles of successful migration, and back again to breed successfully. If the tags and rings affected the birds' behaviour, it would make the research invalid.

A member of the Loch Garten team will climb up the nest tree and carefully take the chicks out of the nest. They'll be lowered down to the ground in a bag.

Before fitting the tags, Roy will examine each osprey thoroughly to check that it's healthy and strong. He'll also take some biometric measurements – weight and wing length – and we'll find out what sex the chicks are. The birds' welfare and safety always comes first.

As in previous years, he will ring each chick with a British Trust for Ornithology lightweight metal ring and a coloured plastic leg ring on the other leg, to help identify them in future. The tag is attached to a harness that the bird wears, a bit like a tiny rucksack.

The adult ospreys will return soon afterwards to carry on feeding as normal.

The tag will operate for three years, provided the battery is charged with good levels of sunlight from a little solar panel. Sometimes the tags don't work so well while the birds sit around in trees around the nest, but they shouldn't be short of sunlight once they head towards the Mediterranean.

In the Loch Garten Osprey Centre (until the end of season closure in early September) we'll have a flat-screen television hooked up to the internet so you can follow the ospreys' adventures.

If you can't join us in the Highlands, don't worry – you'll be able to keep up with the latest news on the RSPB website, using Google Earth satellite maps to pinpoint their locations.