Rare osprey chicks previously extinct in England fitted with identifying rings in Northumberland
Four rare osprey chicks have been lowered to the ground by Forestry England climbers to be fitted with unique identifying rings and weighed and measured.
The species was until recently extinct in England, but it is making a big come-back in the nation's biggest forest.
The identifying rings will allow ornithologists to track the birds and map their family.
Forestry England ornithologist Martin Davison said: "It's always a highlight of the year when we start ringing the Ospreys. Always.
"If you want to know anything about a bird, you've got to identify it. And that's where the rings come in. The birds will disperse away from Kielder. And remember, these birds are wintering in Africa. So when the birds return, we can tell who's mated with who. We can come along and look at the nests and say, right, that male's mated with this female, that male's from Kielder."
Scientists say that to have four chicks on one nest is exceptional adding that the parents of this brood are some of the most successful in the forest, breaking all local records for the number of offspring.
Joanna Dailey is from the Kielder Osprey Project. She said: "They've raised nearly a quarter of the birds that have fledged from here. They've been together since 2013.
"They're our longest-running pair and they're magnificent to watch because you just feel this is what it should be all about everywhere. That's such a reward to watch a successful pair like that.
"She's been an amazing mother. And so it's nice that they're getting the reward of of their chicks thriving fledging and some of them will come back in the breeding."
Listen to ITV News' What You Need To Know podcast: