A group of 40 enthusiasts dashed to the Hebrides to catch a glimpse of the brown, black and blue bird, which breeds in Asia and winters in Australasia.
But instead of being treated to a wildlife spectacle they were left with a horror show when it flew into a wind turbine and was killed.
John Marchant, 62, who had made the trip all the way from Norfolk, said: “We were absolutely over the moon to see the bird. We watched it for nearly two hours.
“But while we were watching it suddenly got a bit close to the turbine and then the blades hit it.
“We all rushed up to the turbine, which took about five minutes, hoping the bird had just been knocked out the sky but was okay.
“Unfortunately it had taken a blow to the head and was stone dead.
“It was really beautiful when it was flying around, graceful and with such speed. To suddenly see it fly into a turbine and fall out the sky was terrible.”
The last sighting of a white-throated needletail was 22 years ago.