The egg was laid at about 0410 BST on Friday
An elderly female osprey has laid her 50th egg at a Perthshire bird reserve.
It happened at the Loch of the Lowes, near Dunkeld, at about 0410 BST.
It is the first egg of the season for the osprey. More are expected in the next few days.
Ospreys tend to average only 30 eggs in a lifetime.
Volunteers and staff will mount a 24-hour guard to protect the nest until the chick hatches.
North East reserve manager, Rab Potter, told the BBC Scotland news website it was "fantastic news" that the osprey had laid an egg.
He said: "We have surveillance 24-hours at the moment and will continue to do so until the chicks have hatched.
"We have a group of about 70 local volunteers who help us do that.
"Our main threat would probably come from potential egg thieves.
"It may perhaps be seen as a challenge [to steal the egg] because it's such a high-profile bird."
The bird has been nesting at the Loch of the Lowes since 1991.
There had been questions about the paternity of any potential chick because the female was seen mating with a bird who was not her usual partner.
However Mr Potter said she only mated with the other male, who was her son, once.
He feels it is more likely her usual partner is the father, as they have mated many times.