Monday, March 14, 2011
Yellowhammer alternating song types
The course of an old railway line between Knockentiber and Springside in Ayrshire provides some good scrubby habitat for Yellowhammers (Emberiza citrinella). While surveying the territorial males there last May, I heard one bird that was singing two song types which were alternated almost one after the other. Most of the birds in this area sing about eight strophes (or deliveries) per minute and stick to one song type for quite long periods, though occasionally dropping the final ‘cheese’ phrase. Listen to this excerpt of a recording below of this bird and you’ll see what I mean. The first strophe I’ve termed the ‘Fast High’ song type/strophe and the second, the ‘Slow Low’ song type/strophe.
The ‘Fast High’ strophe is around 1.84 seconds with the first phrase comprised of a rattle of 10-11 syllables spanning 4.22-6.76 kHz and lasting 1.07 secs. The second phrase – just a single element, and the familiar ‘cheese’ of the popular British mnemonic for this species – is around 4.85 kHz and lasting 0.68 secs.
The ‘Slow Low’ strophe is longer at around 2.11 seconds with usually 12 lower-pitched rattles spanning 3.07-5.04 kHz and lasting 1.37 secs. The 'cheese' phrase is also lower pitched at 4.4 kHz, lasting 0.55 sec.
Another element in the song that is quite difficult to detect in the field with the human ear (and while listening to playback of recordings) is the very short (0.04 secs) and high pitched (up to 8 kHz) element that immediately proceeds the rattle. It is visible on the sonogram but see if you can pick it out in the recording.