Sonograms - no rise or fall in pitch

Herman van der Meer kindly provided this sonogram of the soundrecording by Theo Muusse. Theo recorded several calls of the tristis, either did Jaap Dijkhuizen. I am grateful to this help of my friends! Accepting this record by the CDNA will be peanuts now.

Sonogram recording 29/11 - Theo Muusse/Herman van der Meer

The sonogram shows clearly the typical, sonore 'chickencall': 'whee'. Note that the flat line bows a bit down a the end of the calls. But 'no rise or fall in pitch', as Mark Constantine would say.

Recording Theo Muusse With in the background a Water Rail. Recorded with a Sony LS10. Nice device!

More about the calls of Siberian Chiffchaff: Mark Constantine & The Sound Approach 2006: p. 27, 90 and 105.