CHIFFCHAFFS FROM THE SOUTH-EAST (2020)
- short note, thinking out loud
- ssp. brevirositris or caucasicus proven on DNA in the Netherlands and Germany
- can these vagrants be identified in the field based on calls?
Figure 1. Mystery Chiffchaff, 22 February 2015, Lauwersmeer, Groningen, the Netherlands: is this a bird all the way from the Middle East or Transcaucasia? (Martijn Bot/ Birdingholland.nl)
Who would have thought chiffchaffs from Turkey or Transcaucausia could end up in NW Europe? But they did! Molecular analysis proves no less than three birds either belonging to ssp. brevirostris or caucasicus have been sampled in the Netherlands and Germany. This web note gives a little background, and focuses on the vocal ID of these taxa. Because there might be Dutch field records, too!
Peter de Knijff already mentioned these three birds in his lecture on the Dutch Birding Day in 2018. During late 2015, two birds with brevirostris/ caucasicus mtDNA were sampled in the Netherlands and one in Germany. Whether these birds are from Turkey (brevirostris) or Georgia, Armenia or northwest Iran (caucasicus), they originate from a very unexpected corner!
A paper summarizing our 10 year genetic study on chiffchaffs is expected to be published this year. More details and photographs will be shared later.
Interestingly, the German bird uttered a “sad” call, reminiscent of Siberian Chiffchaff (Jochen Dierschke in litt.). Unfortunately it was not recorded, but that surely does fit a bird from the south-east!
A field sighting of a puzzling chiffchaff on 21-28 February 2015 in Lauwersmeer, Groningen, the Netherlands came to mind. Due to its odd calls the bird was initially reported as a possible (but extremely unlikely) winter record of an Iberian!
It’s intriguing that former rarity committee member Rik Winters mentioned the similarity of the calls with brevirostris at the time (here). With birds from the south-east now being confirmed as vagrants, I wondered if this also sheds light on the ID of the Lauwersmeer bird. And, consequently; can these south-eastern vagrants be recognized in the field? This is what the Lauwersmeer bird sounded like:
Dimitri Mulder, who found the bird, recorded these "down slurred" calls. With a descending pitch (somewhat Siskin-like), it's no wonder he thought of an unseasonal Iberian!
Same bird, recorded a week later by Ellen de Bruin
Figure 2. Mystery Chiffchaff, 22 February 2015, Lauwersmeer, Groningen, the Netherlands: could this be a bird all the way from the Middle East or Transcaucasia? (Martijn Bot/ Birdingholland.nl)
For starters, plumage of the mystery bird - especially the greenish hue, the yellow on the lores and brownish legs, does not a fit a Siberian Chiffchaff. Though the leg colour could fit, it doesn't seem to have the long primaries and long bill of a 'classic' Iberian either (though they tend to be variable). I don't know much about plumage features of south-eastern birds, but the calls might help.
Slightly 'problematic' is that at the time of writing (February 2020) only calls outside the breeding season of the south-eastern taxa were available on xeno-canto. That's rather inconvenient for a call-analysis, since I do not want to mix things up with a possible migrant from elsewhere.
Fortunately José Luis Copete – who has been working on chiffchaffs for a long time – was kind enough to share some breeding season calls of Turkish birds.
Common and Scandinavian Chiffchaffs are easily excluded, even by ear. I will therefore focus on Iberian, Siberian and Turkish/Caucasian (for now I'd say too little is known to separate these on call with certainty, but see conclusions/ questions).
A very typical Iberian by Jorge Letão, Vila Real, Portugal, July 2018 (XC428200) - similar, but not identical! Note higher pitch.
A very typical Siberian from the core-areas in Russia by Albert Lastukhin (XC336654). Note these calls are nearly "straight".
Breeding season brevirostris calls from José Luis Copete, May 2008, Osmaniye, Turkey. To the ear, this is more like it!
brevirostris/caucasicus (outside breeding season) by Johan Buckens, March 2019, Antalya, Turkey. Hmmm, similar vibe but sounds different.
Maybe the sonagrams shed some light on this. I blew them up to see more detail.
Figure 3 (below). This is the Lauwersmeer bird.
Average duration per call 0,18 (n=5; +0,01/- 0,03). Range: 4,75-3,5 kHz (usually 3,75)
Figure 4 (below). I first compared the Lauwersmeer bird with Iberian. These calls are obviously shorter and they descent more steeply in pitch. Both calls end around the same frequency, but the start of the call is (also audibly!) higher in Iberian.
Average duration 0,14 (n=5 calls, 2 ind; - 0,02). Range: 5,5-3,5
Figure 5 (below). Siberian then. The duration is similar, but these call hardly drop in pitch, they are almost 'flat'.
Average duration 0,18 (n=10 calls, 2 ind; +0,01/- 0,01). Range: 4,5-4
Figure 6 (below). Now let's have a look at the brevirostris from Turkey from José. The range of the frequency is almost exactly the same! It drops in pitch just like the Lauwersmeer bird does, from roughly 4,75 kHz to 3,5/3,75! The calls recorded by José are a bit shorter though in length though.
Average duration 0,18 (n=10 calls, 2 ind.; +0,01/- 0,03). Range: 4,75-3,5 (usually 3,75
Figure 7 (below). This is the Lauwersmeer bird again, just for comparison.
Figure 8 (below). What about the presumed brevirostris/ caucasicus calls from Johan then? Well, the range differs a bit, the shape perhaps, too (slighty), but the length in this bird is very comparable.
(n=5; 1 individual):
Average duration 0,17 (n=5 calls, 1 ind. +0,01/- 0,02). Range: 4,5-3,1 (ending frequency variable: 3.1-3.5)
Conclusions and questions
With Chiffchaffs from the south-east now being proven as vagrants to NW Europe (on DNA), the next question is: can we ID them in the field? Well, maybe we can! IMO the calls of the bird in Lauwersmeer in 2015 match those made in Turkey better than they match any other taxon. A perfect match was not found though, but with all individual variation within chiffchaffs in general this is might not be all that surprising. I'm actually convinced it's not an Iberian or a Siberian, so what other options are there? Sonagrams of birds from Armenia and Iran recorded by Alan Dean seem to be different, flatter, more Siberian-like (bottom of page). Calls from both brevirostris (especially) and caucasicus in Clement et al. (1998, pdf; also depicted on Alan's website) look far more similar at first sight. I'd love to see more detailed ('stretched out/ blown-up) sonagrams of these calls. And the one 'uprising' call of caucasicus raises questions: could that be a migrant? Or are they really that variable? A lot of questions still surround brevirostris and caucasicus. Can they be separated on plumage? Many more recordings of both taxa from the breeding grounds would be very usefull for a detailed analysis. Stuff we, as a birding community, will probably find out in the future. Birds like the one at Lauwersmeer can hopefully be identified with more certainty then.
First of all José Luis Copete shared recordings of brevirostris from the breeding grounds. Martijn Bot, Ellen de Bruin and Dimitri Mulder (who found the bird) kindly gave permission to use there sound recordings and/or photographs of the Lauwersmeer bird. Without Peter de Knijff's DNA-analyses I would never have guessed chiffchaffs from the SE might reach NW Europe.
Dean, A., 2017/2019. Southern forms of Chiffchaff Phylloscopus collybita: observations from Iran and Armenia, personal website. Hyperlink.
Clement, P. & A.J. Helbig, 1998. Taxonomy and identification of chiffchaffs in the Western Palearctic. British Birds 91: 361-376 (pdf)