document: David was one of 60 cuckoos fitted with trackers by the British Trust for Ornithology (BTO) from 2011 and has made return trips from Africa since.
  But his tracker fell silent a few months ago.
  A team on BBC Radio Wales' Country Focus is now trying to lure David into the Tregaron woods using a fake female.
  Presenter Gilbert John said: "We're hoping to find out whether the lack of a signal for David shows that he is dead, or simply his equipment [is dead]."
  The BTO tracking project was set up to discover why half the UK's cuckoos have been lost in the last 20 years.
  Since 2011, many of the birds have died or their transmitters have failed, with David one of the remaining six that make  the migration from the Congo rainforest, where they winter, to Wales.
  In previous years, he has returned to the UK between 28 April and the 14 May and experts expected him to be on the move from his wintering location, if not back on his breeding grounds, by now.
  The BTO has set up a mist net, a plastic cuckoo and the accompanying recording of a female in woods in Tregaron.
  "The hope is to entice David if he's within earshot. [Although], I have to admit, she's not a very attractive cuckoo," said John.
  Kelvin Jones, Welsh development officer at the British Trust for Ornithology, said a lot of people think the newer satellite technology would eliminate the need for the more traditional "ringing" system.
  "But without the ringing system - that is catching the birds and handling the birds - we cannot use the new technology," he said.
  Mr Jones said the tracking project had started to unravel the mystery of cuckoo movements.
summary: Conservationists are searching for a missing cuckoo called David who usually returns to his Ceredigion breeding grounds.