Dug out a notebook on bird behaviour I started 20 years ago in 2000. The first entry in the book was of a Common Cuckoo seen at Barbondale, it was published in the British Birds issue in January 2002.
The Call of the Common Cuckoo.
I watched a male Common Cuckoo through a telescope at Barbondale in Cumbria. The bird was calling continuously for several minutes before flying off. During my observations, I realised that the call was produced through the nasal, and that the bill appeared to remain closed throughout. Further observations of the Common Cuckoo 2 years later at the same location, confirmed to me, that the birds bill did indeed appear to remain closed, and this behaviour was new to me.
British Birds Editorial Comment.
The first syllable of the familiar advertising call of the male Common Cuckoo is delivered with the bill opened, whereas the second syllable is uttered with the bill closed. As demonstrated by the observations reported here, there appears to be some variation in the manner in which the call is delivered. BWP Vol.4
There was an interesting follow-on by Dr T.J.Roberts to the notes on 'Call of the Common Cuckoo' in the issue of British Birds November 2002.
The note by Pete Woodruff in British Birds January 2002, prompts me to add the following observations, based on 34 years living in Pakistan. In the Himalayan foothills, I was able to observe at close quarters the Common Cuckoo, the Oriental Cuckoo, and the much less common Lesser Cuckoo, at times calling from the same area. I noted that all three species of Cuckoo kept their bills closed when calling, while the gular pouch, or throat, ballooned out visibly with each call. I recorded these observations in detail in The Birds of Pakistan.
Red Admiral. Pete Woodruff.
A Red Admiral was the first this year to our garden, and as an occasional visitor, it was good to see a Coal Tit in the garden this morning.