"There is more variability in Iberian Chiffchaff song than is currently recognised, and I have recordings of two birds singing in Portugal in May 2007 that have a rather monotonus song consisting of a series of flat ‘chip’ or ‘whit’ notes, sometimes ending in a more rapid series of stuttering notes. "
One of my birding highlights of 2007 was the Iberian Chiffchaff Phylloscopus ibericus at Norwich, Norfolk, UK. Recently, a short section of the bird singing on Roy Harvey’s video ( posted on Surfbirds Video) renewed my memories of the bird. However, the video also raised again for me the memory of an odd chiffchaff found singing in Suffolk at Lavenham in May. The frustration of this bird revolves around its very odd song and, after examining the identification of Iberian Chiffchaff and its occurrence in the UK, I will discuss this bird, include some images and more importantly some recordings of the song in the hope that some light might be shed on its identity. I would be very grateful to anyone with the experience who has an opinion if they could shed light on it!
Iberian Chiffchaff has had an odd taxonomic history, with the form initially described by von Homeyer (1871), who advocated that chiffchaffs from Iberia constituted a specific form. He described it from a specimen from Portugal under the name ‘Phyllopneuste Brehmii’, and considered it a distinct species. This Iberian specimen (oddly) displayed characters not usually associated with Iberian Chiffchaff (brown olive upperparts, a different wing-formula with shorter second primary and secondaries, and smaller sizes. At the time Homeyer made no mention of any vocal differences by which the species might be separated from Common Chiffchaff. The holotype of this specimen (now deposited at the Staatliches Naturhistorisches Museum in Braunschweig, Germany) was recently examined by Svensson (Bull. BOC 2001; 121 (4); pp.281-296) and found to be a Common Chiffchaff, as were two other von Homeyer’s specimens: one at the same museum; the other at the Museum of Natural History Tring. Svensson described a new ‘Ticehurst type’ specimen collected in Portugal in 1920, now at Tring, and renamed the species as Phylloscopus ibericus.
In a second detailed study of Iberian Chiffchaff (published in 2003), Salomon, Voisin and Bried (Ibis, 145, 87–97) go further than just describing Iberian Chiffchaff as a species. The authors propose a ‘split’ into two subspecies: nominate ibericus, breeding ‘in an area composed of relatively wet Mediterranean habitats, mainly cork-oak formations sparsely spreading from central Portugal (Coimbra region) to southern Andalusia’; and biscayensis breeding in ‘a region spreading between the extreme north of Portugal and Galiciato the French basque country across the Cantabrian Cordillera (northern and southern slopes), the Spanish Basque provinces and Navarra (Fig. 1). This area is characterized by a wet Atlantic climate, moist and mild throughout the year’. The results of the analyses also show clear-cut biometric differences (relative to the ibericus, biscayensis ‘has significantly longer wings, longer 10th primaries and, relative to body size, shorter tarsi (both sexes) and shorter and wider bills (males only)’, as well as breeding allopatrically in two disjunct regions of Iberia. [The maps in Salomon et al are inaccurate, as I have seen many Iberian Chiffchaffs breeding in coastal woodland north-east of Alcacar do Sal – they show it restricted to a central ‘spine’ running north to Coimbra].
The identification of Iberian Chiffchaff is almost solely based upon the song and call, and despite some extremely subtle plumage and bare-part differences, there is no other certain means by which they can be identified with absolute certainty in the field. The typical and most well-known song of Iberian Chiffchaff is a characteristic rather short song phrase, made up of short rising and falling notes followed by a simple rattle: this is often transcribed as ‘huit huit huit hweet j-j-j-j-j-j’, or variations on that theme. Also, it is now known that the call of Iberian is rather different to that of Common Chiffchaff Ph. collybita, a downward inflected ‘siu’ - this slightly sad and plaintive call is very different from the flat ‘hweet’ calls of Common Chiffchaff and forms a useful further identification tool, especially on migration in, for example, Morocco.
There are a number of recordings of the song and call of Iberian Chiffchaff on the internet. The best ones are on the Dutch Birding website http://www.dutchbirding.nl/, where there are lots of sound files (go to sound gallery then scroll down and use the search engine to find Iberian Chiffchaff – there are also recordings of odd chiffchaff songs and Common ChiffchaffxWillow Warbler).
There is a poor video of a Dutch bird singing.
Here are two recordings of the call of Iberian Chiffchaff I made near a nest in Portugal in May 2007 (on the second you can hear the song of a male in the background).
There is more variability in Iberian Chiffchaff song than is currently recognised, and I have recordings of two birds singing in Portugal in May 2007 that have a rather monotonus song consisting of a series of flat ‘chip’ or ‘whit’ notes, sometimes ending in a more rapid series of stuttering notes. These were both made on Monchique in the south of Portugal. These recordings are quiet, so you may need to turn up the volume on your computer.
A small number of chiffchaffs performing odd song phrases have been recorded occasionally in the UK and in the Netherlands. As previously mentioned, there are recordings of these birds (putatively claimed as Iberian) at Dutch Birding, but also one of a bird at Skelmersdale in the UK ( http://media.putfile.com/Skelmersdale-Chiffchaff ). Quite what these birds are is open to question, but some have suggested the possibility that ‘they are mostly first-year birds which have yet to crystallise their song’. There are also purported to be mixed singers from a small contact zone between Common and Iberian Chiffchaffs in the Pyrenees, and such birds when out of range might be hard to identify. It is therefore essential that the documentation of a vagrant Iberian Chiffchaff includes sound-recordings of song phrases and the distinctive call. If you compare the songs of Iberian Chiffchaff above with those of the Skelmersdale bird there are some undoubted similarities, but are we willing to accept these ‘odd’ birds if they fall outside the ‘normal’ range of song?
In addition to the voice characters described above, some very subtle differences in plumage and structure can also be noted: a relatively long tail, wing and bill, as well as bright plumage coloration and well-marked supercilium - the problem with plumage is the variability of both Common and Iberian Chiffchaff plumage. Dealing with plumage characters first, it can be seen that Iberian Chiffchaff is generally a brighter bird compared with Common Chiffchaff; support may be gained from biometrics may help, but only if rather intricate measurements are taken and placed in equations.
Salomon, Voisin and Bried (Ibis, 145, 87–97, 2003) made a comparison of the mantle and breast colours of a relatively small number of Common Chiffchaffs and Iberian Chiffchaffs (34 museum skins, ten were Common Chiffchaffs and 23 Iberian Chiffchaffs). They used a standard colour scheme called the ‘Code Universel des Couleurs’ of Séguy (1936)’ which contains 720 of the colours ‘most frequently encountered among living organisms’, each is given a code number (between 1 and 720), which are further translated into vernacular expressions like ‘turquoise blue’ or ‘vermilion red’, etc. In their study, Salomon et al describe the Iberian Chiffchaff as displayin ‘a ‘bistre-green’ (261 or 262) mantle and a uniformly coloured breast – its coloration spanning from pure white to buffish yellow, but mainly lemon yellow (white, 234,250, 258, 260, 265, 320). However, in the Common Chiffchaff, the mantle has an ‘old moss-green’ (276)or ‘holly-green’ (301) colour; and the breast is a less pure hue – whitish either soaked with buff, or with various greyish tinges (259–336; 260–522; 260–524).’
In Svensson (Bull. BOC 2001; 121 (4); pp.281-296) the brightness of the upperparts has been, in my opinion, greatly over-exaggerated: he describes the upperparts of Iberian Chiffchaff as ‘moss-green’ (note that in the Salomon study they equate ‘old moss-green’ with Common Chiffchaff), ‘about as green as in Wood Warbler Ph. sibilatrix’, and with a more saturated green hue than in Willow warbler Ph. trochilus’. This is surely an over-statement and I would say that actually Iberian is similar to Willow Warbler and to most eyes Iberian is slightly more olive above than Common. Iberians I have seen in Portugal in May are often rather tatty, as they must arrive early, breed early and start to moult early, and their upperparts can seem quite dull.
The prominence of the supercilium, amount of yellow in the supercilium, face, breast and vent does, as Salomon et al point out, seem quite consistent in Iberian, but I wonder whether some Commons may match this. The legs also seem to be a paler brown in Iberian than in Common; the bill which sometimes seems more spikey, tends to have the lower mandible totally pale and slightly less flesh (ochreous in colour).
There are in-hand, biometric differences in the wing formula, but they do seem to be incredibly complicated, and are they truly replicable – with ringers often getting small, but significant differences in measuremnts of the same bird. For example, there are two formulae, by Salomon et al and by Svensson.
The first discriminant function reads: (0.283 x wing length) – (0.036 x length of p10 – innermost primary) + (0.269 x wing pointedness index*) + (0.31 x tarsus); if the value is over 26.4 then it should be Iberian, if below it should be Common. [* wing pointedness index is found by dividing the distance between the tips of p3 and p10 by wing length x 100]. Confused? Imagine trying to remember to take all of the relevant measurements on a live bird in the hand and then applying them to the formula; an error of 0.5mm would have big repurcussions to the results, and Svensson says he found it ‘did not work well on my material’
Svensson’s ‘multiple character value’ for Iberian Chiffchaff is designed ‘with ringers and field workers in mind’. To get the value you must first add seven measurements: wing length; bill length – to the skull; distance from p1 (outermost primary) to p2; distance from wing-tip to p6; distance from wing-tip to p7; distance from wing-tip to p10; distance from wing-tip to s1 (outermost secondary). Then you must substract two: tail length and the distnace from p1 to the primary coverts. He writes this as MCV = W + B + (p1<p2) + (p6<WT) + (p7<WT) + (p10<WT) +(s1<WT) – T – (p1>p.c.). For males, a MCV higher than 73.2 should mean Iberian; an overlap area between 71.9-73.2 exists; anything below 71.9 should equal Common; for females the discrimant value is 70.9. Svensson found 89% of male specimens and 56% of female specimens could be identified by his formula.
A greater primary projection has been proposed for Iberian in some of the literature, but Svensson’s measurements (Bull. BOC 2001; 121 (4); pp.281-296) of 10-14mm for males and 9.5-12.5mm for females are almost identically matched by Common Chiffchaff (9.5-14mm and 8.5-12.5mm respectively). Even the longer bill that seems apparent in the field is not borne out by measurments.
The differences in structure are so slight, and in-hand formulae necessary for identification so convoluted, I don’t know what anyone else thinks, but I think it is best to stick to the voice!
The first Iberian Chiffchaff to be accepted for Britain was at Brent Reservoir, Greater London, on 3 June 1972 – this bird was seen in the field but more importantly it was heard to sing and call with a tape recording made of it. Since the first, there has been a total of 13 records in the UK, all being first identified by their song. Most UK-based birders had their first chance to hear the distinctive song from an Iberian Chiffchaff at Portland, Dorset in 1999 (Birding World 12: 193-200), whilst the first Iberian Chiffchaff for the Netherlands was recorded at Baarn, Utrecht in the spring of 1967. By 2006, there have been a further 17 records have been accepted for the Netherlands, and it appears to be more or less annual in occurrence.
Pete Hobbs found a chiffchaff singing along a disused railway line at Lavenham, Suffolk, UK, on April 13th 2007. Though it’s territory was over 400m distant from his house, he could even hear it from his garden; despite there being public access, given the uncertainty surrounding the identity of the bird, publicity of the bird was initially tentative. When I was contacted in the evening of May 13th, PH had already begun to think that it might actually be an Iberian Chiffchaff – the song was so different to normal Common Chiffchaff. I went to his house the next morning to listen and see the bird, and as it got light the bird was easily heard and seen. I made a series of video recordings - the sound recordings of the bird here come from PH; the photographs were taken by Bill Baston.
[cut 1 is a good example of its more excitable song; cut 2 a more sedate and relaxed bird.]
As can be heard, the Lavenham chiffchaff’s song has similarities with both Common and Iberian. It would start with the nasal chirrup, which both species have, then would cut into a rather slow jumble of chiff notes interspersed with faster series’, being almost Wren-like at times, It never sang like a typical Iberian Chiffchaff, but it also never sang like a typical Common. It displayed to another chiffchaff also present, and so when a Chiffchaff was heard calling its normal ‘hweet’, I was not 100% sure which bird it was that called. I never heard the diagnostic, plaintive ‘seeoo’ at any stage.
The plumage of the bird, as can be seen from the excellent series of photos obtained by Bill Baston, was indeed pretty bright: the supercilium, face and breast were particularly bright yellow – though the super was more obvious in front of the eye than behind; the undertail coverts seemed rather paler yellow; the upperparts were bright for a Common Chiffchaff. The bill was quite yellow and the legs at the pale brown end for a chiffchaff. If we look at this bird in the light of the description of plumage in Salomon et al (Ibis, 145, 87–97, 2003), one might think that it is indeed an Iberian Chiffchaff, and if the song is found, or decided, to be that of an Iberian Chiffchaff, then we will have to change our perceptions of what an Iberian Chiffch aff can sound like. If, however, the Lavenham bird is thought not to be an Iberian and just a Common Chiffchaff, with its ‘odd’ song just that, odd, then it can be seen that the morphological characters mooted for Iberian simply cannot be applied in the field.
Thanks to Pete Hobbs for finding and recording the bird; also to Peter Kennerley for transfering them to mpeg format.