Cuckoo...heard but not seen!

Just travelled up from Portugal via Spain and France. On 21st March we were with French friends at Breuillet, near Royan and all heard a cuckoo calling from the nearby woods. Great excitement all round and a fab way to recognise Spring is on the way...perfect date too!

 Might it be on its way to UK or do they only call once in their chosen habitat and looking for a partner???

Happy birding!