The Rhyl Warbler - by David Winnard

This blog entry is intended to try and add to the discussion about the Phylloscopus warbler that turned up at Rhyl Brickworks on the 11th November 2019. Here are some of my thoughts and findings so far, but I welcome anyone who has other images or more importantly, sound recordings of the bird to share them. I am by no means an expert on either species for the record.

Monday 11th November 2019 is a day that I will remember well, I was due to trade in my old banged up Toyota Yaris for a new one, so I was at home sorting out car insurance and getting the paperwork work ready for that afternoon. Then at 12:58 a message appeared on my phone "Hume's Leaf Warbler in car park at Rhyl Brickworks. Constantly calling during the 5 mins I was there but blowing a gale". The message was from Alex Jones, the finder of the bird, and indeed it was blowing a gale, the weather was awful, but a Flintshire (in terms of recording area VC51) Hume's Leaf Warbler was too good to miss; my real birding passion in North Wales is my Flintshire list too. Hume's Leaf Warbler would be a 4th for Wales, 3rd for North Wales and 1st for Flintshire (VC51). So I set off in my banged up old Yaris with my camera with the intention of trying to get some evidence of the bird to make sure it would pass any rarity committee, a sound recording would be perfect.

Travelling up from Queensferry it took me around 35 minutes to arrive and I was the only person in the car park, not surprisingly, it was raining and must have been gusting 40-50mph, I was sure there was no chance of finding this bird. Not a sound of a warbler either. After 20 minutes I was still alone looking, then a Long-tailed Tit flock arrived and I was sure it would be in with them, one by one they flew past right in front of me, nothing. Then a few minutes later I heard a call that was not familar too me, and then the bird appeared right in front of my eyes.

The previous year I was lucky enough to find a Yellow-browed Warbler in Flintshire on my patch (although I have seen others elsewhere), picked up on call, and even now I can hear the distinctive call ringing in my ears. This bird at Rhyl was not making that noise, it was shorter and different somehow. I got my phone out to try and get a sound recording, but as soon as I did that it shut up. I must have heard it call 4-5 times and each call was short and not the distinctive 'seaweed' call of a Yellow-browed Warbler. After getting a few brief glimpses through my binoculars, it sat partly obscurred by some small branches not far from me and started to preen. I tried getting a few pics, the wind blowing everything around and the camera not picking the bird up and wanting to focus on every twig and leaf around the bird instead. Then a moment where the sun came out, directly behind me and I managed to get on the bird and fire off a few shots before the bird disappeared through the trees.

A few other birders then finally arrived, although the bird had skulked off, I tried to search for it with them for a little while but my car insurance changed cars at 3pm (after all I was not meant to be out birding!) and if I left any later it would have meant driving back with no insurance. So I left, desperate that the news of it still being there would come through, and by the time I got home it had been seen by others. I quickly editted the above image, posted it on Twitter and off I went to get my new car.

By the time I was home, doubts were circulating on Twitter if this was a Hume's and not just a Yellow-browed Warbler. The bird was too bright and the feet were too pale but the photo was taken with the full sun behind me so was that just exaggerating the features? Surely it was just that wonderful brief spell of beautiful sunlight that was casting these doubts, and what about the call, not calling like any Yellow-browed Warbler I have ever heard.

Some people were arguing that the camera is lieing and in reality the bird was paler. Now here is where I disagree, the camera never lies, but the photographer can. Having spent three years gaining a BA in Wildlife Photography then there are lots of tricks I know on how to create an image to look warmer, cooler, more vibrant, more saturated you name it and it can be done. But the camera just records what it sees, it is down to us to then tell our story in the edit. So over the next hour I started playing around with different edits, if I made it cooler perhaps it would show the birds duller colour, or the legs would be darker. No. Everything pointed to it not being 'grey' and having pale legs. But the call...

I was busy on Tuesday and could not go back for another look, I really wanted to record its call (although again the weather was awful), that way it would be certain as to what the bird was. It was still being seen and others were hearing the bird and all were saying Hume's Leaf Warbler. So the image must just be an odd pose whilst preening and in beautiful wintery golden light making the bird look 'warmer'. As far as I am aware no one got anymore pics or any sound recordings on the Tuesday; that night discussions were still taking place on the ID of the bird and still the majority I spoke with were with Hume's, mainly on call.

The weather was much calmer on Weds 13th November. News came out in the morning that the bird was still there and 'showing well', which means people will have got images, good, now we can compare to my image from Monday. But had anyone got a sound recording? Even on mobile phones you can record something, it might not be perfect but you will be surprised. I turned up around midday, no camera today, others had got pics, I was just interested in sound recordings and after 20mins of no luck, the bird having disappearing after showing so well (but apparently did not call pretty much all morning, so no sound recordings) I was beginning to think it was never going to happen. Then after a short while the bird was found and again calling, though not frequently. I got my phone out and started recording, the bird was a bit faint but it made one call, not calling like a Yellow-browed Warbler, and I got it on the phone. 15 minutes later the bird appeared quite close, 'showing well' (typical when no camera in hand) and called a few more times - a few differenty calls, but not frequently and the phone was struggling to pick it up. But surely something to look at an analyse? The bird disappeared again but I wanted to try and get some better recordings so I stook around.

Then bingo! A proper Hume's Warbler call, disyllabic in nature identical to a recording I was listening to in the car on the way up. I walked round the corner to where it was calling ready to record it and there were two men playing the call to try and attract the bird. In fact the reason why it sounded so familar is they were playing the same recording I had played in the car! A wave of frustration came over me. In the next 30 minutes at least 4 more people were playing Hume's Leaf Warbler calls from devices and I was finding it hard to know what was real and what was recordings. I had assumed that people with their phones out were trying to record the bird, but it was becoming clear they weren't. I could not relocate the bird and gave up.

The Look

Pictures were emerging on social media from various birders who had taken photos of the bird during the day, so now it was possible to see how they compared to my images from Monday in terms of plumage colour, leg colour etc.

Dylan Edwards managed to get a few shots, and importantly they were in 'duller' conditions, no harsh light and the bird is slight shadow. Yet the birds legs still looked pale, the bird still had a nice contrast in it with warm tones, especially in the crown and upper parts. When I saw the picture it was not looking good, in fact so much so the bird news services re-identified the bird as a Yellow-browed Warbler from that picture alone.

The bird had been photographed in two extremes of light and both showed the same thing. But the call...

Photo by Dylan Edwards.

Photo by Dylan Edwards (cropped image from above)

The Sound

Back at home I was excited to download what few recordings I had and although faint surely they would prove something. I had been reading up on the sonograms of both species and there is an interesting article that was published in 2001 in Dutch Birding Vol. 23 (5), p. 275 by Teus J. C. Luijendijk called 'Vocalisations of Yellow-browed Warbler and Hume's Leaf Warbler in autumn and winter'. In it Teus states "In general it can be said, that humei's (Hume's Leaf Warbler) call hardly ever reaches a frequency higher than 6 kHz...On the other hand, the call of inornatus (Yellow-browed Warbler) almost always reaches a frequency of 7 kHz or even higher".

I pulled up the first recording...

The top end was nearly at 7.5KHz, not good. But the call is too short and not right for Yellow-browed Warbler surely? Teus (2001) in his article also states that "On average, the duration of the contact call of inornatus (Yellow-browed Warbler) is over 0.30 sec., a length humei (Hume's Leaf Warbler) never seems to reach". Well this call is closer to 0.20 sec.

I then tried going through a number of websites looking for sonograms of Hume's Leaf Warbler making a similar call. It is said that Hume's can have quite a varied array of calls so perhaps this is one of them. No luck, I could not find anything for Hume's that matched.

I then started looking over sonograms of Yellow-browed Warbler from various sources and found something very similar on xeno-canto.org, I then tried putting the two sonograms together with the frquencies aligned. Not a typical Yellow-browed Warbler call, but someone else had recorded a Yellow-browed Warbler in Brittany, France, doing a very, very similar call. Even the length of call, much shorter than the traditional call, was the same.

Stanislas Wroza, XC443439. Accessible at www.xeno-canto.org/443439.

(My recording on the left, the Brittany bird recording on the right)

What about some of the other calls I had recorded, they weren't the best recordings by any stretch of the imagination, but could I find any Hume's recording with a similar pattern? No. Again back to Yellow-browed Warbler. Below the comparison again of the bird calling, not typical Yellow-browed and shorter too, but someone else had recorded a Yellow-browed doing the same call, this time on Cape Verde. Again well above the 'normal' frequency for Hume's.

Marcin Sołowiej, XC456851. Accessible at www.xeno-canto.org/456851

(My recording on the left, the Cape Verde bird recording on the right)

The last call I recorded, a different call from the others and not as high frequency, surely there were no sonograms of Yellow-browed Warblers doing this call? At least two looked very similar, and considering my recording was not the best, again same note type call, same frequency and and roughly the same length as the others too. These birds were from Yell (Shetland) and Island Schiermonnikoog (Netherlands).

Dougie Preston, XC39394. Accessible at www.xeno-canto.org/39394

Sander Bot, XC149179. Accessible at www.xeno-canto.org/149179

(My recording on the left,the Shetland bird recording middle, Netherlands on the right)

What I find interesting is all the birds 'non typical' calls I found have been recorded well out of their 'normal' range, France, Scotland, Netherlands and Cape Verde. Is there a reason for this or is it simply there are more birders carrying sound recording equipment in these areas? Or is it because these birds are rare in these parts they are more likely to get recorded?

Conclusion

I have found this bird fascinating. The birds call is not a 'typical' Yellow-browed Warbler and all the calls I heard and recorded are much shorter than the norm. But the frequency seems to be too high for Hume's and I can not find any sound recordings that match for Hume's. Yet for 3 totally different calls I have found, in my opinion, sonograms that match from other recordings of Yellow-browed Warbler.

Let us not forget the plumage, the warm tones especially in the crown and upper parts, the pale legs and feet, the yellow in the supercillium and even birders there had said, if it had not have called it would be a Yellow-browed Warbler all day long. From the photos being posted many observers were saying from the pics alone it is a Yellow-browed Warbler. It was not just the beautiful golden light for the brief window on Monday when I took the first shots that were making the bird look bright and pale legged, the bird was actually like that.

There is an interesting article to another similar case as this one from Scilly in 2012, having spoke to a few people about it it seems this bird is now thought to be a Yellow-browed Warbler too. Have a look at the article here http://www.rarebirdalert.co.uk/v2/Content/humes_scilly_2012.aspx?s_id=480827887

So what is my humble opinion on the bird?

How does the saying go....if it looks like a duck and a quacks like a duck....

**Since writing this article I have had an email from Magnus Robb (soundapproach.co.uk) who has kindly taken the time to make his own sonograms of the same calls I recorded, he writes, "For this bird I would be thinking Yellow-browed Warbler. Nothing about the calls really suggests Hume’s to me, and they are not too low for Yellow-browed. However, clearly they are not the most typical call you hear from Yellow-browed".

*A big thank you to Alex for finding the bird and sharing the sighting as well as discussing the ID with me, and also to Henry Cook for his contributions and to everyone else who has been in touch about the bird.