After all the driving out to Tarout Island and Futaih and then back again yesterday, I decided to stay local this lovely Saturday morning* and headed to Al Ahsa National Park. I’m hoping to turn up Pallid Scops-Owl there in the tall tamarisk trees that can be found throughout the park, but to do that will require spending an unknown number of hours prowling beneath the trees, scanning the branches near the trunks, and muttering supplications to the birding gods in the hopes I get lucky. Today marked the start of what just may become another Saudi birding obsession in line with my ongoing quest for Dunn's Lark. Ultimately though, no owls today, but the nice weather and a few new sightings for the spot made it an enjoyable morning.
For starters, a late Eurasian Wryneck was working its way up a Mesquite Tree like a proper woodpecker, true to its familial affiliation, and the freshening north wind this morning brought a small flight of Greater Spotted Eagles soaring by. Then, of course, I turned up a few of the resident Black Scrub-Robins, a couple of which were singing somewhere in the treetops. However, the birds that kept me the busiest were the dozens of Lesser Whitethroats of the halimodendri subspecies, which were all around the park this morning. The past few visits have proven that this is a great place to find whitethroats.
Now even those still relatively new to birding in this part of the world are sure to be familiar with the Greater Whitethroat (Sylvia communis), a common spring (April – May) and fall (August – October) migrant in Arabia. However, when it comes to pinning down just what “Lesser Whitethroat” you’re looking at, the situation becomes a bit more challenging. This is due in part to how subtle some of the differences between the various subspecies of Lesser Whitethroat (Sylvia curruca) are and also to the fact that ornithological authorities don’t agree on just how many subspecies there even are, where they range, and which of them might warrant full species status.
Currently, the accepted wisdom is that three taxa from the “Lesser Whitethroat complex” occur in Saudi: Lesser Whitethroat (Sylvia curruca curruca), Central Asian Lesser Whitethroat (Sylvia curruca halimodendri), and the rarer Hume’s Whitethroat (Sylvia curruca althaea). The nominate subspecies (S. c. curruca) in the superspecies group that is the “Lesser Whitethroat complex” is a common spring and fall migrant, whose passage more or less lines up with that of the Greater Whitethroat. By mid October the “Desert Whitethroat” begins showing up from the steppes and deserts of Central Asia and can be encountered throughout the winter. A fourth form, the Siberian Lesser Whitethroat (S. c. blythi), is said to winter in Arabia but that’s a taxon in the complex not considered viable by some, and I’ve yet to see any reports of birds fitting their description in these parts.
When I first came to the Middle East, the “desert” form – sandier brown above than the nominate – was regarded as a separate species (Sylvia minula) as was Hume’s Whitethroat (Sylvia althaea). However, these birds refuse to be pinned down and the debate continues as the taxonomical authorities variously split, lump, and reassign the taxa that comprise the complex. Recent research has banished Sylvia minula to a more restricted breeding range in western China, so the “Desert Whitethroat” frequenting Arabia in the winter is now believed to be S. c. halimodendri, aka the Central Asian Lesser Whitethroat. Unfortunately, the Birds of the Middle East, currently the only guide to the region on the market, hasn’t been updated regarding the recent developments in the taxonomical designations of lesser whitethroat subspecies since I bought my first copy back in 2010. While the descriptions coupled with the illustrations are sufficient for separating the “desert whitethroat” forms from Sylvia c. carruca and Sylvia c. althaea, halimodendri only receives mention in the description of Sylvia minula and only as a migrant in the region at that. Any visiting birder would be best advised to bring another field guide – I recommend Collins Bird Guide – and do some additional research on those trickier subspecies.
Unlike Hume’s (Lesser) Whitethroat, which are often silent on passage, halimodendri call constantly. During my time in the UAE, I got comfortable IDing them by their call alone, which is faster and more rattling than S. c. curruca – check out the audio I recorded today of halimodendri’s call on Xeno-Canto. Besides the call and the sandy-brown upperparts fading into the gray of the cap and cheeks, I wasn’t really clued in to any of the other diagnostic features for this form until today. I spent a good portion of the morning trying to get decent images and video of the birds, especially footage of them singing, which I could then convert to audio files for Xeno-canto and Cornell's Macaulay Library. Thankfully I captured what I needed to fully distinguish these birds from the nominate Lesser Whitethroat and the Hume’s Whitethroat.
Overall, the desert form from Central Asia is smaller, shorter beaked, and with a shorter primary projection than the other two. The upperparts are a light sandy brown that gradually fades to gray up the nape to the bird’s cap. Like the other lesser whitethroat subspecies, there’s a partial white eye-ring around the lower half of the eye, but on halimodendri the lores and ear patch are a darker gray than the rest of the head, creating a more distinct masked appearance. The extent of white in the tail feathers is a critical means of separating them from the other subspecies occurring in Saudi. Whereas as S. c. curruca has white showing only on the outermost tail feather, S. c. halimodendri shows white on two or three of the tail feathers, as can be seen in two of the images above.
As with birding in general, there’s alway a new frontier, always new things to learn, and today I learned more about these charming warblers.
* Originally posted on November 2019