The first osprey eggs are expected to hatch in the coming days - with one set of parents having a relationship that would be frowned upon if they were human.
This year's chicks could start hatching as soon as Tuesday. However, cooler weather in recent weeks mean that it's not certain, with Joanna Dailey, Kielder osprey observer saying that there is not an "exact science" to knowing when they hatch.
The birds of prey, which return to nest and mate at Kielder in Northumberland after wintering in warmer climes, tend to mate for life, but if one's partner dies, they will mate with a new one. And one of this year's mating pairs, who have already produced an egg, are mother and son.
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However, it's not as uncommon as you may think. According to Joanna: "It's not unusual for birds to breed with other members of their family, in fact it's quite common in some species.
"It's not common in ospreys, but it's certainly not unknown. In bird species, the genetic diversity is huge as they've been around for millions of years so it's not like it would be in the human race."
Their egg is one of 18 estimated to have been laid across the eight nests in Kielder Forest since the first osprey returned to Kielder Forest at the end of March 2023. This year's first egg expected to hatch is on nest 4 and belongs to a returning mating pair of many years.
Despite the estimated 18 eggs, two nests remain unoccupied. Joanna continued: "We're slightly down in terms of occupied nests because a couple of bids didn't return from migration.
"There are two nests that haven't got pairs on, which is disappointing for us because you'd hope another bird would take their place but that hasn't happened."
The birds winter in Spain, Portugal and West Africa, and there are a number of threats which can prevent them from returning home. These include unpredictable weather conditions, occasional shooting in Spain and Portugal, while off the coast of Gambia and Senegal, birds can get caught in fishing nets.
She finished: "It's very unusual for the older male who hasn't returned not to be back in the last week of March. The other is a female who has bred here since 2019.
"We don't know exactly how old she is but she's probably about 7 or 8 and you'd expect ones that age to get back. If they've bred successfully they're going to return to the area they bred in and the partner they bred with, so the fact that we haven't seen her is fairly conclusive that she hasn't made it back."
The Kielder Osprey Project is a partnership between Kielder Water & Forest Park Development Trust, Forestry England, Northumberland Wildlife Trust, Northumbrian Water and Calvert Trust Kielder. Osprey Watch will take place every Saturday, Sunday and Wednesday from April 8 to August 13 between 11am - 4.30pm, with visitors offered views of the nest via scopes and a close up on nest 7 via a camera in the cabin.
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