Chiffchaffs wintering in Kuwait : which subspecies?
Chiffchaff, Al Abraq, Kuwait, December 2nd 2013
Certain Chiffchaffs wintering in Kuwait have enigmatic plumage and calls. The crown and mantle are olive-brown while the underparts are rather pale, with relatively limited yellow streaking. However, there are evident olive fringes to the flight-feathers. The plumage lacks the rusty-buff or 'tan' suffusions typical of Siberian Chiffchaff. Their call is short and can sound similar to tristis to the human ear. Indeed, visiting birders have often equated this call with tristis. However, there is a subtle 'sweeoo' sound to the call, which starts on an even pitch but then rises and then falls. It has a distinctive shape in a sonogram, rather like a 'hook' tipped on its side (see below).
Fig. 1. Call of Chiffchaff ay Jahra, Kuwait, November 2013
The call can be heard here ►. Siberian Chiffchaff calls vary to an extent and include at times a shallowly but evenly arched variant. The 'inflection' in the Kuwaiti chiffchaffs' call is much more pronounced and is positioned towards the end of the call. Within c. 0.1s it rises and falls approximately equally either side of the pitch of the opening section. Hence the inflection is not readily perceived by the human ear and confusion with a tristis call can result. The subspecies involved in these Kuwaiti Chiffchaffs is subject to a great deal of speculation, with suggestions including menzbieri. The 'hooked' shape does not match any of the sonograms of Chiffchaff races published by Helbig et al. (1996) and repeated by Clement et al. (1998). However, the first call illustrated in section 'k' and attributed to caucasicus in Helbig et al. closely matches the flat opening and the rising pitch at the midway point. It apparently lacks the terminal downward turn (just conceivably this been truncated in the recording or subsequent processing of the sonogram, as the downstroke is abrupt and has less impact than the rest of the call). Its attribution requires confirmation, especially since the genetic studies of Raković et al. ( 2019) have brought into question the precise distributions of caucasicus and menzbieri. However, the shape of the Kuwaiti calls is very different from the typical and distinctly straight ('flat') call of caucasicus. A similar shape is evident in calls recorded by Cedric Mroczko at Alogol in NE Iran and placed on xeno-canto (xc513431). Being on the border with Turkmenistan, this location would be within the breeding range of menzbieri but, as the recordings were made in November, it is conceivable that another taxon may be involved.
Fig. 3. Calls of Chiffchaff from Alagol, NE Iran, Nov 2019. Sonogram prepared from recording by Cedric Mroczko on xeno-canto.
See <here> for sonograms and discussion of Chiffchaffs in the central Elborz mountains of Iran, a region spanning the ranges associated with caucasicus and menzbieri.
In Azerbaijan, on March 19th 2012, Timo Janhonen recorded Chiffchaffs with a call comparable to those in Kuwait, with an evenly pitched ('flat') opening followed by a terminal arch . The recording is available <here>.and photos <here> on Tarsiger. The breeding form in Azerbaijan is deemed to be caucasicus but the early date does not confirm birds established on territory. There were several such birds but Timo Janhonen states (in lit.) that they were in lowland shrubberies and meadows by the Caspian Sea (rather than the forest) and, consequently, it is impossible to know whether they were arriving near their breeding grounds or were migrants en route farther afield. Timo also noted a very similar call <here> on xeno-canto (xc212252), recorded in Azerbaijan in January 2015 by Steve Klasan, so individuals with this call apparently winter in the region. Clarification of the distribution limits of caucasicus and menzbieri and the range of their calls is required.
Fig. 4. Calls of Chiffchaffs from Azerbaijan, March 2012
(left), Azerbaijan January 2015 (centre) and Kuwait, November 2013 (right).
(Azerbaijan sonograms prepared from recordings by Timo Janhonen (left) on Tarsiger and Steve Klasan (centre) on xeno-canto.)
Interestingly, in an item on tristis call variants (http://www.elisanet.fi/antero.lindholm/Linnut/Phylloscopus/tristis/trcall.html), Antero Lindholm includes a call with this same distinctive shape (the second call in example 5 - note that the captions and recordings, although somewhat displaced, are positioned below the corresponding figure). However, this call was recorded in Oman in November 2002, so its attribution is perhaps hypothetical. It would not be surprising if the Chiffchaff taxon involved in the Kuwaiti sightings also reached Oman.
Many thanks to Timo Janhonen for providing recordings and other useful data from Azerbaijan, Antero Lindholm for discussions of the Chiffchaffs found in Georgia and adjoining regions and xeno-canto for providing a public platform for sound-recordings.
CLEMENT, P., HELBIG A.J & SMALL, B. 1998. Taxonomy and identification of chiffchaffs in the Western Palearctic. Brit. Birds 91: 361-376.
HELBIG, A.J., MARTENS, J., SEIBOLD, I., HENNING, F., SCHOTTLER, B. & WINK, M. 1996. Phylogeny and species limits in the Palearctic Chiffchaff Phylloscopus collybita complex: mitochondrial genetic differentiation and bioacoustic evidence. Ibis 138: 650-666.