Over the last 20 years the number of cuckoos in the UK has halved.
In order to learn vital information which can help to understand what is happening to the cuckoo, the British Trust of Ornithology (BTO) has been satellite-tracking the species.
PJ was tagged in June 2016 in Suffolk and has since been providing the Thetford-based BTO with knowledge about cuckoo migration.
He is one of only two BTO cuckoos to have gone as far south as Angola - a 4,500 mile journey.
The information received from the tag identified this as a new wintering location.
Last year he returned to Suffolk on April 29 where he remained throughout the breeding season before beginning his migration to Africa for the winter.
He took a more central route from the UK to Angola avoiding the western route where there have been fatalities in other tracked cuckoos.
Dr Andy Clements, chief executive of BTO, says: 'BTO's migration tracking research is pioneering.
'Six years into the programme we continue to discover new facts. For example, some of our cuckoos winter in Angola, previously not well known as a wintering location for UK migrants.'
PJ has now begun to move north, travelling from Angola to Cameroon, on his way back to Britain,
This year the BTO are also tracking another seven different cuckoos - Boris, Larry, Mr Conkers, Peckham, Samson, Selborne and Victor - and following their migrations.
In 2009, the cuckoo was added to the Red List of Birds of Conservation Concern.
Although there was a lot of knowledge on the cuckoo's breeding behaviour while in the UK, little was known about their migratory behaviour.
Through the satellite-tracking the BTO has found out that British cuckoos only spend a small amount of their time in the UK.
One of the tagged cuckoos spent just 15pc of his time in Britain, spending 47pc in Africa and the rest on migration.
The cuckoos followed so far take a different return route to the UK than the one they followed on their outward autumn migration
If you would like to follow PJ and the other cuckoos visit the BTO website.
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