Sykes's Warbler - Hippolais rama

Sykes's Warbler has occurred once at Portland, on July 1st 2000. The record was fully documented in Birding World (13: 274-276), as follows:

They say lightning doesn’t strike twice in the same place, but when, at midday on 1st July 2000, PBO warden, Martin Cade, came across an unfamiliar grey-and-white warbler trapped in one of the mist-nets at the Observatory - almost a year to the day after an Eastern Olivaceous Warbler Hippolais pallida elaeica had been found there in similar circumstances - he might have been excused a distinct feeling of déjà vu.

In truth, any further similarity between the two occurrences quickly evaporated. Whereas the Olivaceous Warbler was easily identified, here I was confronted with a bird that I was unable to immediately place to genus, let alone species. It so resembled an Acrocephalus that my initial thought was that it must be Blyth’s Reed Warbler A. dumetorum. However, anomalies were soon apparent: it had, for instance, pale edged outer-tail feathers and horn-pink legs. These features, as well as the short under-tail coverts, led me to consider the smaller Hippolais warblers, but, perplexingly, none of these seemed to fit either: it was too small for Olivaceous Warbler, but also had the wrong head pattern and too large a bill for Booted Warbler H. (c.) caligata. With this cursory examination of the bird leaving me none the wiser, I set about obtaining as full a range of measurements and photographs as possible.

It soon became apparent that the measurements appeared to eliminate all other possibilities except one that I had not so far seriously considered: Sykes’s Warbler H. (c.) rama. Unfortunately, rama was not covered in detail in the literature immediately to hand (Svensson 1992), and, although identification by default was less than satisfactory, time was pressing and I had to release the bird.

Initially elusive after release, the bird became more visible as the afternoon went on, and it was eventually seen by more than 200 birders. Field observations supported my earlier provisional identification, but it was not until subsequent study of the literature (e.g. Cramp 1992 & Williamson 1968), and a review of the measurements and photographs by Lars Svensson, that the identification could be confirmed beyond doubt.

In the hand, once it was established that the bird was a Hippolais warbler, identification was restricted to just three possibilities: Sykes’s, Booted and Eastern Olivaceous. The table below sets out some of the most important differences in measurements and wing-formula between these forms. These clearly place the Portland bird within the range of rama, as well as excluding the other two forms.

	Portland bird	rama	caligata	elaeica
Wing length (maximum chord)	60	59-65	57-64	62-71
Tail length	52	48-56	43-50	48-59
Bill length (to skull)	15	14.8-16.3	12.9-14.5	15-17.4
1st primary > primary coverts	7	--- 6-10 ---		3-7
6th primary < tip of wing	2	---1-3 ---		3-6
10th primary < tip of wing	10	--- 8-11 ---		11-15
emargination on 6th primary	faint	--- present ---		absent

The measurements bear out what was immediately apparent in the hand: this was a very small, but long-billed and long-tailed bird, lacking the Phylloscopus-like character of caligata. Compared to caligata, its upperparts were colder grey-brown, and its underparts were cleaner silky-white; it also lacked conspicuous white eye-crescents, and did not have a dark tip to the lower mandible. Close examination revealed no trace of a dark upper border to the supercilium, although, surprisingly, there is a suggestion of this feature in some of the in-hand photographs.

In plumage the bird was very like elaeica, but, in addition to its smaller size, there were significant structural differences. The tail was relatively longer, and the primary projection was relatively shorter; also the tertials were unevenly spaced, with a longer gap between the shortest and middle feather, than between the middle and longest (these feathers are usually evenly spaced in elaeica).

Lars Svensson (pers. comm.) has reviewed the measurements and photographs, and commented as follows…“The Portland Hippolais is in every respect a typical rama. Tail/wing ratio (x100) is 86.7, which is conclusive in itself (caligata never exceeds 82.1, and usually has <80), and bill to skull is outside the range of caligata. The distance between the tips of primary 1 and primary 2 was not given, but working from one of the photographs I have calculated it to be 24.5mm, which conclusively eliminates elaeica (which has 27-33). Tail pattern also eliminates elaeica, as do several other details. There are some tricky birds with intermediate characters in one or a few respects….but your bird shows no hint of mixed characters”.

*Syke's Warbler Hippolais rama* at Portland on 6th July 2000**
Wing length (maximum chord)		60
Wing formula, primaries numbered ascendently:	P1	primary coverts + 7
	P2	-4.5
	P3	= longest
	P4	= longest
	P5	-1
	P6	tip broken,estimated -2
	P7	-6
	P8	-8
	P9	-9
	P10	-10
to 1st secondary		-11.5
Primaries 3, 4 and 5 strongly emarginated, primary 6 very weakly emarginated
Notch on 2nd primary 15 from tip of feather
Notch on 3rd primary 14 from tip of feather
Tail length		52
Tail difference t1-t6		4
Bill length to skull		15
Bill length to feathering		11
Bill width at proximal edge of nostrils		3.7
Bill depth		2.6
Tarsus length		19

All measurements in mm (measured as per Svensson Identification Guide to European Passerines)

Views in the field confirmed the structural and plumages details already noted in the hand, but also revealed other features that further supported the identification. On release, the bird showed well for half-a-minute or so, calling frequently and giving a series of slow, shallow, upward tail-flicks. The call was a Lesser Whitethroat-like ‘teck’ - similar to, but distinctly quieter and less penetrating than, the calls given by the Portland Olivaceous Warbler in July 1999.

Later in the afternoon, observations were more prolonged, although the bird was often rather lethargic and spent a good deal of time motionless - seemingly sunning itself. During this period it kept almost exclusively to the middle and tops of trees and shrubs, and was rarely observed feeding low-down in caligata fashion.

At times, a diffuse dark upper border to the supercilium - a feature that had been invisible in the hand - was an arrestingly obvious plumage mark on what was an otherwise rather plain bird; the prominence of this feature appeared to be strongly influenced by posture, subtle changes in feather positioning, and angle of view. Latterly, and in contrast to the earlier observations immediately after its release, the bird rarely called, and the only tail movements seen consisted of occasional downward flicks followed by slight sideways twitches (Richard Millington (pers. comm.).

I am very grateful to Lars Svensson for kindly, and authoritatively, commenting on the identification of this tricky bird.

Svensson, L. 1992. Identification Guide to European Passerines. 4th edn. Stockholm.