A pair of ospreys have returned to their Gwynedd nesting site for the fifth year running.
The ospreys are thought to be the only nesting pair in Wales
The male bird arrived at the nest at Glaslyn, near Porthmadog, on Monday, followed by the female on Wednesday.
Observers said the male began displaying immediately, flying high into the air and calling, before the pair started mating 20 minutes later.
They are the only known nesting ospreys in Wales, and fly in from Africa every year to raise chicks.
There was initial concern that the male was not the same bird that has returned for the past five years, as its orange tag was missing.
Staff feared any intruder could have clashed with the regular male.
Emyr Evans, RSPB Cymru's osprey officer said: "The orange ring was an easy way to recognise the male but this has now gone.
"The ring would receive quite an impact each time he plunges in the water to catch a fish, plus he has just completed a long and arduous migration.
"The ring could have come off anywhere between Wales and west Africa - we won't be trying to find it."
Two chicks fledged from the man-made nest in 2005, followed by another two in 2006.
Mr Evans added: "This pair have arrived back even earlier than last year, and are probably among some of the first ospreys to arrive back in the UK.
"It's as if they couldn't wait to get back to sunny Wales."
A viewing platform at the Pont Croesor site will be open to the public from Saturday, and live images from the osprey nest-cam will be shown in the visitor centre.
Around 56,000 people visited the centre, run by the Royal Society for the Protection of Birds, last year.
Ospreys survive on a diet of fish and are most commonly seen in the UK in Scotland.