MAY 2010'S MYSTERY BIRD ANSWERS

An inspiring 29 entrants 'gave it a go' this month, a good return on what looked on the face of it to be a reasonably simple round, or so some thought. Was it all that clear cut though? Is it ever? Let's take a closer look.

Mystery Bird 9

A bird in a bush and on the face of it, a little brown job too. Despite it's apparent featureless first glance there are a few significant traits which can quite swiftly assist us to narrowing down our identification. Firstly though let's look at what it isn't. Reed Bunting managed a single vote but our bird lacks any of that species' much brighter edges to the wing feathers, pale mantle 'stripes' and the tertials of Reed Bunting (as with many species of buntings) have distinctive tertial patterning very different to the pale edged items of our mystery bird. Corn Bunting received two votes, not really too bad an effort but despite one or two other erroneous features for that species, our mystery bird appears to have a rather slim bill just about visible. Rock Pipit got a mention with a single vote but too has several features which are out of place for our mystery bird, most damning being primaries which are practically completely cloaked by the tertials in comparison to our bird's which are clearly fall well short of the primaries. Dunnock received the most incorrect votes with three and it's easy to see why. It's not dissimilar to our mystery bird being a particularly streaky species but would be expected to display much more bright colouration on the remiges and mantle, some white tips to the greater coverts and even in this pose we'd surely see some flank streaking. That leaves our correct answer of which 76% of the entrants managed and it was, Grasshopper Warbler. Or does it? Two entrants atleast mentioned Lanceolated Warbler in their reckoning and despite it not actually gaining a single vote how would we go on separating it from our mystery bird? Well, typically with no small amount of difficulty! Lanceolated (though exceptions and overlap does occur in virtually all features) has very dark, black tertial centres with a stark contrast between them and the paler edges. They are usually more clear cut and even in width than Grasshopper Warbler but those tertial edges on our mystery bird in actual fact (on the image provided) are not dissimilar to those we'd expect on a Lanceolated Warbler, so caution is called for when claiming the next one somewhere in the county! Lanceolated Warbler usually has a shorter, more rounded primary projection and certainly to my eyes from the handful I've seen in the field, a shorter tail. It's darker mantle patterning has a blackish centre reaching all the way to the tip so that the streaking appears continuous, un-broken. Grasshopper Warbler conversely possesses a mantle feather pattern of a complete pale fringe which gives rise to a more 'scalloped' look to the mantle streaking where each individual feather is more obvious. On the mystery bird photo provided, the latter feature is difficult to make out but the photo below illustrates it a little better. Either way and as difficult and subjective as it might be from the original photo, nobody suggested it anyway but patently, a full suite of features is called for in the identification of a Lanceolated Warbler, preferably with some nice photos of the bird as it clambers around your feet!

Grasshopper Warbler, Pennington Flash, April 2010 (Ian McKerchar)

Mystery Bird 10

It's all too easy sometimes isn't it. Big, full frame photo, all the features there right in front of you. Yet we still get it wrong? In fact, occasionally, these full-framers, the apparent dead obvious ones, are the ones that lead us astray. There's no intent to mislead I promise. The photo is as I received it, complete with the incorrect identification and I had to make my own judgement to correct that. So how did our intrepid Manchester Mystery Bird Competition entrants judge it?

Well, they decided that seven species were potentially involved so clearly it was never that cut and dried in the first place! All but one entrant suggested that the bird was anything other than a phylloscopus warbler, with Icterine Warbler managing a solitary vote. Our subtle but effective use of assessing the bird's jizz confirms the bird's identification as indeed a phylloscopus Warbler, clearly lacking the overall larger, bulkier feel of Icterine with a much slimmer based bill, distinct supercilium behind the eye and lack of any pale wing panel amongst other features. That left us with six species of phylloscopus Warbler, Wood, Bonelli's, (Common) Chiffchaff, Greenish, Willow and Iberian Chiffchaff. Let's go for the throat and bin what we know to be wrong. Chiffchaff (two votes) goes by the wayside thanks to it's clearly shorter primary projection than our mystery bird. The latter's primary projection is roughly equal to the length of the tertials and no (Common) Chiffchaff comes close to that, although it's always worth checking that all three tertials are present before judging this feature! Greenish Warbler (one vote) goes next. It too has a rather short primary projection and should exhibit a clear pale wingbar along the tips of the greater coverts which our bird does not. Although wear can impact on how pronounced the wingbar might be we would still expect to see something and these wing feathers appear quite fresh in any case. We might also not expect any Greenish Warbler to be quite so bright yellowish but having seen the Lizard Point, Cornwall bird of late autumn 2009 they clearly can be, despite not generally being illustrated in field guides as such! What of Bonelli's Warbler (one vote)? Not right either I'm afraid. They are much more distinctly greyer on the upperparts in both species (Western and Eastern), never so yellowish, have a rather plain, featureless face and once again a shorter primary projection. Now we're whittling them down we get to the still (in my personal opinion) slightly murky waters of Iberian Chiffchaff (which received one vote) and the fact that someone was bound to suggest it! On plumage alone it's a decent option no doubt but reference to the primary projection once again shows that, despite Iberian Chiffchaff having a slightly longer projection than (Common) Chiffchaff, it does not approach the considerable length of our mystery bird. This leaves just two to fight it out, Wood and Willow Warbler. Wood Warbler received the majority of the votes with 45% whilst Willow Warbler managed to raise 34%.  Both species have a very long primary projections and although Wood's is slightly longer, assessing it as a feature to separate the two from the image is tricky and not necessarily definitive. Both species could perhaps be shoe-horned into fitting our mystery birds plumage features, save potentially for two, those being the pattern of the tertial edges and of the 'face'. Wood Warbler has distinctly contrastingly tertials, dark in the centre and pale on the edges, outers in particular. Our bird though seems to have retained old (unmoulted) tertials which appear rather greyish and patternless so are of perhaps little value? The face however tells a subtly different story. Wood Warbler has much cleaner ear coverts than Willow Warbler, with a much stronger yellow wash and little more than a dark eye-stripe and edge to the very rear of the ear coverts. Our mystery bird however has quite extensively brownish ear coverts with very restricted yellow hues. This gives us our clue as to our birds true identity but is it enough to positively claim it as such? Well, for me, the overall look of the bird, lacking in really extensive deep yellow (check out the rear of the supercilium and throat especially which are more washed yellowish than the deeper more vibrant lemon-yellow we'd expect of a Wood Warbler), not really pure white underparts (check out the rear flanks/vent) and much less vivid green on the upperparts and remiges all lend themselves to the mystery bird's identity being secured as a Willow Warbler. To finalize matters though and drive the decisive nail in it's coffin, as an advocate of both using jizz and feather minute in my bird identification/assessment there is one glaring feature which separates the two instantly. Our mystery bird has a displaced first primary, the single obvious feather below the greater primary coverts and this makes it easy to see when usually it is hidden underneath the other primaries. It's length is clearly twice that of the aforementioned greater primary coverts, a feature shared by Willow but not by that of Wood which has a first primary slightly shorter than the greater primary coverts. See, sometimes feather minute wins through! The dark legs of our mystery bird, should you ask, are merely an occasional occurrence within the range for Willow Warbler, potentially misleading of course but nevertheless possible as in this instance.

Only ten entrants nailed this mystery bird, though perhaps only the ringer amongst them utilised the first primary length in his appraisal but either way, well done to them all. Simon Warford, James (household bragging rights) Latham, Mark Rigby, Nick Green, Mike Cooper, Henry Cook, John Tymon, Paul (pulled a few of those out of his nets) Brown, John Frankland and Iain Johnson.

Willow Warbler, Bahrain, April 2010 (Adrian Drummond-Hill)

This round saw only nine entrants manage a clean sheet, an excellent achievement in a tricky round. Simon Warford, James Latham, Mark Rigby, Mike Cooper, Henry Cook, John Tymon, Paul Brown, John Frankland and Iain Johnson.

This round also saw a clear leader emerge at this stage of the year with Paul Brown now the only entrant with ten correct answers so far. Of course there is still a hard chasing pack behind him and the pressure is now on Paul to maintain his perfect score. Can he, will he?

Oh and by the way, many thanks to everyone who joined in again this month. Always appreciated, you can be sure of that. This competition might just yet live on!

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