An ornithologist for the Roy Dennis Wildlife Foundation, Tim Mackrilll, said it was not one of the eagles the organisation was tracking from the Isle of Wight.
He said: “I suspect it is a juvenile from Scotland.
“There are now around 200 pairs of white-tailed eagles in Scotland and we know that young birds can be highly nomadic in their early years.”
Having seen pictures of the bird, Mackrill believes it fledged last summer and it was be exploring for the first time.
Chief executive of the Northumberland Wildlife Trust Mike Pratt said he was “delighted” to hear the eagle was in the area.
He said: “What a treat for members of the public and bird watchers alike.
“I’m delighted that such a wonderful bird chose to touch down at a number of our reserves along Druridge Bay and our Holywell Pond reserve near Whitley Bay.”