Friday, May 25, 2018

High expectations, slim pickings

I left Norwich early this morning with Phil and Will, with soaring expectations: weather conditions could have not been better for a fall, and/or for something really good. Burnham Overy Dunes was our choice. We were surprised to be the first birders there. As we walked out, the White-winged Tern showed nicely, albeit distant and in bad light conditions. A bird I wouldn't twitch in the UK, but was still really nice to bump into:

White-winged Tern

We worked the dunes hard, again and again, from Gunn Hill to the woods. At first there were no migrants to be found at all; evidently there was no fall. In those moments of disappointment, someone always uses the useless phrase 'biggies always travel alone'. If there were any biggies around, we missed them. News started to pour in, of decent arrivals and scarcities elsewhere in Norfolk and along the east coast; this enthused us to do another circuit of the dunes, and another... Then we had to move on, leaving the dunes goodies to be found by others. Between our group of 4/5 (including James and Dave Appleton) we did find eventually singles each of Pied Flycatcher, Common Redstart, Tree Pipit, Whinchat and Cuckoo. There were also 3 Wheatears, presumably local breeding birds. A Little Ringed Plover flew by uttering its sad call over the saltmarsh, and a Merlin bombed around Gunn Hill. On the marsh the distinguished residents showed OK - Spoonbills and Great White Egret. Two Barn Owls hunted out in the open - always fun. On the way out, several Bearded Tits pinged from the reedbed, and among a distant group of lingering Brent we found a striking Pale-bellied. The total for the morning was 95 species (check my eBird checklist here) - not bad I guess. And if you read the list above it feels like a pretty good morning. However, my expectations were much higher, both for quality and numbers. But hey, better to look at the bright side and enjoy what we did see, which ain't too shabby.

Stonking male Pied Flycatcher

Pale-bellied Brent

Barn Owl

Some other fauna and flora included:

One of quite many Wall Brown

Female Muslin Moth

A scarce hoverfly identified by Phil - Scaeve selenitica

Southern Marsh Orchid

We then went to Titchwell for a quick visit. The Greenish Warbler was surprisingly vocal in the midday (relative) heat, and showed OK, demonstrating its very faint wingbars; sadly I failed to get a decent photo.

I sound-recorded its vocalisations with my phone. Song came out rather OK; I need to work more on the calls. James got similar results with his iPhone...
We drove back by Choseley, where we added Corn Bunting and Yellowhammer to our day list, bringing it up to 99. 
Thanks to Will for driving there and James for driving back; good day out - maybe there still is another chance for a fall or a biggie this spring.

Sunday, May 20, 2018

Why I think the Mt. Amasa wheatear was chrysopygia

On the 10th of March this year an intriguing wheatear was found in Mt. Amasa, on the southern slopes of the Judean Mts. This is one of my favourite parts of the country and birding there in march is just brilliant. The bird was first noted by Igal Milchteich and David Raved. At first it was identified as a female Kurdistan Wheatear (Oenanthe xanthoprymna). Very nice but nothing too extraordinary - several are recorded in Israel annually. Then some doubts arose regarding its identification, because of its large size and very long bill, and general plumage tones that didn't quite fit. Only a few days later images of its pale underwing coverts were taken, suggesting it was in fact a Persian Wheatear (Oenanthe chrysopygia) - boom! 2nd record for Israel if accepted. First record was in 1990 in Nizzana.

This image is by Rami Mizrachi, showing nicely the pale underwing:

I was most intrigued by the prominent rufous tips to tail coverts, something I have never seen on Kurdistan Wheatear before. Obvious also in these images by Micha Mandel:

Check the monster bill in this image:

A few days later Yosef Kiat trapped the bird, measured it and kindly allowed me to use his photographsץ Yosef idenified it in the hand as a 2cy.

Grey crown and nape, and rather contrasting rufous ear coverts:

Pale underwing coverts, and pale throat:

During my brief visit to Israel for Champions of the Flyway I paid the bird a quick visit, and was really impressed by its size, elongated head and long bill; it felt very different from my experience with Kurdistan Wheatear, which is smaller, with a 'cute' round head and shorter bill. I didn't get very good photos of it, sadly:

During Champions of the Flyway, I had some discussions on the bird with Hadoram Shirihai and other birders who saw the bird. Hadoram raised doubts about the identification as chrysopygia, and told me about scary hybrid populations that could look similar to our bird. As a good student of Hadoram, I learned never to accept the wisdom of others more experienced than me, and doubt everything said to me. 
A few weeks ago I visited Tring. After I was done with my main mission (Nubian Nightjars), I had a short while left to give the wheatear trays some love and attention before the museum closed down. I took quick measurements of chrysopygia (n=13) and xanthoprymna (n=18) - I focused on three measurements: bill to skull, amount of rufous on T1 (central tail feather) and T6 (outer tail feather). Here are the results:

First - bill to skull. In literature (e.g. here), xanthoprymna has a longer bill than chrysopygia. I found the contrary. Based on my measurements, chrysopygia bill (mean 19.6 mm) is much longer than xanthoprymna (mean 17.3 mm)there is even no overlap between the two taxa. You don't really need statistics to tell that this difference I measured is highly significant. The Israeli bird (blue star) fits right at the top of the variation of chrysopygia that I measured (20.4 mm).
In all graphs (this one and those below), thick black line is median, and top and bottom of boxes are the 75th and 25th percentiles respectively.

Next - rufous on inner and outer tail feathers. Here, chrysopygia shows more rufous at the tips of both tail feathers - means of 3.65 mm on T1 and 3.42 mm on T6, compared to xanthoprymna with 1.64 mm and 1.36 mm respectively. These differences in amount of rufous at tail tip between the two taxa are significant too. But this is not the main point. My results show that all chrysopygia I measured had a proper rufous terminal tail band (as implied by its scientific name).
Contrastingly, xanthoprymna showed variation in this feature - some individuals had a tail band and others did not. This means (based on my measurements), that if a bird has a proper rufous tail band, it can be both, so this is only a supporting feature for chrysopygia; if it doesn't have a rufous tail band it is a xanthoprymna. Interestingly, this feature is shown in the plate of Collins Bird Guide 2nd edition, but not in the text. Sadly, Yosef didn't measure the amount of rufous on tail tips, but from photos it is obvious this individual has a proper terminal tail band:

This is an example of a xanthorpymna with more rufous on the tail:

Some necessary caveats about my measurements:
  • My sample size is small - I had very little time and measured the nearset individuals in the trays I pulled out. This is not a complete set of all individuals at Tring - it is possible that I would have found more variation had I obtained a more complete dataset. However, I did a quick visual examination of those individuals I had no time to measure in the trays I pulled out, and apparently they showed a similar pattern.
  • I had no time to check the age of specimens - it is possible that some measurements, e.g. amount of rufous on TF of xanthoprymna, are age-related.
  • Significant geographical variation has been documented in chrysopygia: kingi that is a questionable taxon, and there is a known hybrid zone in western Iran between xanthoprymna and chrysopygia, resulting in another questionable taxon cummingi - check articles here (sorry, can't find the full article online, only abstract) and here. I measured only the tray of 'nominate' chrysopygia, and did not have time for trays of other chrysopygia taxa. However, caution must be taken when accepting a-priori identification of complex taxa in Tring trays. My bottom line is - there may well be more variation in the above measurements within chrysopygia, that I did not measure.
To summarise, in my opinion the Mt. Amasa bird fits with what is currently known about chrysopygia plumage: pale underwing coverts, blue-grey crown and nape, brown ear coverts. The Israeli bird fits well with what I measured as chrysopygia (but this is contrary to some literature); and tail pattern fits chrysopygia too ('which is only a supporting feature).

I don't know enough about kingi and cummingi; however, with the current knowledge and my results here, I suggest this is chrysopygia. I have asked the opinion of several birders who see many chrysopygia, and they have a similar opinion to mine. It is possible that there is an unknown population of chrysopygia with a long bill, that I am not aware of. However, currently, I think it is safe to place this bird in the chrysopygia camp, rather than xanthoprymna or hybrid.
If and when new evidence shows that this individual is closer morphologically to another taxon, I'd be really happy to learn more and reassess my results here.

Now it's up to the Israel Rarities and Distribution Committee to make a formal decision (I am a member, so my vote is clear now).

As always, I am grateful to the staff of the Natural History Museum at Tring for their welcoming and friendly approach, especially to Hein van Grouw and Mark Adams. Many thanks to Rami, Micha and Yosef for allowing me to use their photos here. Anderson Saldanha Bueno assisted with creating these graphs.

Tuesday, May 8, 2018

#bathroommoth 2018

Another season of open window brings some common moths into my bathroom. Mainly micros but some finer macros as well. Nice to sit down and ID them. I often fail with their ID and get assistance from friends with better moth ID skills than me. I have already posted some of these images on Twitter - sorry for recycling.

Streamer was a beautiful addition in late April:

Early Grey roosts on the shower curtain:

A rather early Snout, somewhat disheveled, visited me last night but wouldn't pose nicely. It disappeared somewhere in my house:

Many-plume Moth is very common but really special:

Brindled Flat-body - almost got away on the bathroom window sill:

Bee Moth (thanks Josie!)

 And a couple of tiny micros - quite attractive from up-close. Four-spotted Yellowneck (Oecognia quadripuncta) - I think:

White-shouldered House Moth 

Friday, May 4, 2018

Little Green Yanky Heron

After a few days of not going to see the Green Heron, today I finally joined a few desolate souls who needed it (James, Joe and Will who didn't need it but joined anyway); we set off from Norwich early, though probably not early enough. The drive there was long (6.5 hours) and we got to Llan-mill in Pembrokshire just after the bird had ended its morning show. It was on view immediately as we arrived (tick!), but it was active for just another 20-30 minutes; then it took a siesta. It foraged a bit in the small pond - we saw it catching mainly newts. It is a great looking bird - very bright and attractive, and I am very glad I made all this long way to see it. We had brilliant views, especially through the scope, but photographically I was a bit disappointed with my results using my camera gear. It was just a bit too distant for real quality shots, and often partly obscured by branches. Those who digiscoped fared much better. I missed a foraging jump-shot because I was faffing around with my phone, and got it just as it jumped out of the water. Ah well.

Scanning the sky for a passing Red Kite

Thanks to our hosts Simon and Abigail who generously opened their lovely garden to the many visitors. The pond where the heron is was created and is managed by them. 

There was some bird activity in the garden and its vicinity, including this nice male Blackcap:

For my non-British readers, just a bit of context: This rarity has stirred an extraordinary discussion among twitchers, because of its unique circumstances. Simon Hart who found the bird in his garden was heavily criticised by some birders for his past and present roles in the Conservative Party, Countryside Alliance and SongBird Survival. Countryside Alliance backs intensive management of grouse moors for driven grouse shooting, with all the serious issues related to grouse moor management that include illegal raptor persecution; SongBird Survival has (in my opinion) a controversial attitude towards 'Problem Wildlife'. Some birders called on social media to boycott this bird, and a rather ugly and childish banter began online. Personally, I try not to take this hobby too seriously anyway. I felt that the opinions expressed by some birders, whether I agree with them or not, are irrelevant to this twitch. I am happy that we went for it today.

On the way out we stopped to admire some Early-purple orchids just outside of Llan-mill. Beautiful flowers.

And then it was the looooooong way back. We almost drove back via Harris, but decided to give it a miss this time. Many thanks to James, Will and Joe for a brilliant day out.