it’s all disyllabic
Was out on the Moorland fringe near Sheffield t’other day. Common Sandpiper, Little Ringed Plover and very fresh juvenile Curlew were good value. A Chiffchaff giving the much discussed ‘swee-oo call’ caught my ear. It appeared to be an adult and I never heard it give any other call type. It seemed to be collecting food and on getting near to what I guessed was a nest location (and probably when I got too close) the frequency of calls increased to a level I would describe as ‘virtually continuous’. Interestingly, to the ear it often sounded like a monosyllabic ‘swee’, interspersed with di-syllabic ‘swee-oo’. However (and my hearing could be better!) the sonagrams shows that every note was disyllabic. Have a look and a listen for yourself:
Recording >>here<< (P.S. it was raining too!)
‘Swee-oo’ calling adult Chiffchaff. 22 July 2011. It liked to stay buried in the willows.