Colorado's most famous bald eagle, the Standley Lake female known as F420, is believed to have laid an egg over the weekend.

F420 and her mate, known as Dad, garnered a huge following two years ago — aided by live streaming coverage from the City of Westminster's Standley Lake Eagle Cam — after F420 ran off Dad's former mate and took over the nest. After some initial reluctance, Dad took up with F420 and she laid an egg last year. One eaglet hatched but was killed when the branch on which the nest was built collapsed. The eaglet could not yet fly and was killed in the fall.

F420 sits on an egg in the Standley Lake bald eagle nest on Sunday while Dad hangs out on a branch, keeping watch.

Since then, F420 and Dad took over an abandoned hawk's nest at another location in Standley Lake Regional Park and Wildlife Refuge and enlarged it to accommodate their needs.

Lori Golden, founder of the Standley Lake Eagle Cam Facebook Group, said it was obvious this past weekend that the couple was incubating a new egg.

"Normally the way you can tell when an egg is laid, there's an eagle sitting on the nest," Golden said. "That means they're incubating it, and the other one is sitting on the branch, on guard."

Golden said F420 and Dad are taking turns sitting on the egg. She believes the egg was laid Saturday, which would be 364 days after last year's egg was laid.

Neither Golden nor park officials are disclosing the location of the new nest to prevent crowds from disturbing the eagle couple. The Eagle Cam currently is not operating.

Golden said the new egg likely will incubate for 35-38 days, perhaps 40 if there is more than one, and that it will be obvious it has hatched when F420 and Dad are observed feeding the newcomer. It probably will take another four weeks before the eaglet is tall enough for its head to be seen above the rim of the nest.

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