Autumnwatch's Chris Packham and Kate Humble come to Portland
The BBC Autumnwatch team have been filming on Portland.
It is regarded as one of the most important places for bird migration.
Presenters Kate Humble and Chris Packham visited Portland Observatory in the Old Lower Lighthouse on the island.
Kate Humble said: "There is no better place in the country than Portland Bill to talk about and witness migration."
Chris Packham described his visit to Portland as a 'homecoming'.
He said: "I used to 'migrate' here every Saturday during bird migration season.
"Throughout the eighties and nineties on every Saturday or Sunday during the migration season in either spring or autumn I'd be here on Portland.
"I had a friend who was obsessed by the place."
"At the time I didn't have a car, at least for the early part of that period, and I would camp out at Portland Bill."
"I mean I've stood here, I can tell you about those bushes down there, I can tell you about a bird I saw down by the lighthouse.
"I can tell you about a wryneck I spent about four hours photographing down by the ladies toilet in about 1984!"
Portland Bird Observatory Warden Martin Cade said: "Autumn starts in what most people think of as mid-summer.
"We start to get British breeding birds, such as willow warblers and sedge warblers, leaving in the middle of July.
"Most of those have gone now and will be in Africa for the winter."
Autumnwatch 2009 runs from 2 October to 20 November, Fridays at 9pm on BBC Two. Portland will feature on Friday 9 October.