Nial Moores, Birds Korea, Might twenty sixth 2023
Yearly within the second half of Might, a lot of the survey focus at migrant hotspots turns towards “grasshopper warblers” (Locustellidae). This group incorporates a number of poorly identified, extremely skulking and similarly-plumaged species. Thankfully, every species has diagnostic, and infrequently distinctive, songs – typically given near daybreak and nightfall.
Through the morning of Might 26th, winds had been reasonable and from the south, and the solar broke by way of what little overcast remained from in a single day: removed from promising for locating many migrants. Due to bus occasions, I reached Junghwadong within the southwest of Baengyeong Island at about 10 AM, and continued towards the reservoir, en route listening to a few music phrases (brief, common, rhythmic – as on this recording right here) from a Baikal Bush Warbler Locustella davidi (a reasonably uncommon migrant by way of the northwest of the ROK) and some alarm trills and 1-2 music phrases from 2-3 Pallas’s Grasshopper Warbler Helopsaltes certhiola – maybe the most typical “locust” in spring. It was virtually 11:30 once I then heard a for much longer, deeper, raspier, crackling buzz of a music, given in bursts of three seconds as much as 7 and even 8 seconds or so in size. I instantly acknowledged this music from recordings on Xeno Canto as a Chinese language Bush Warbler Locustella tacsanowskia: a species with maybe just one sight report nationally, and that unsupported by photographs or sound recordings.
Utilizing a small speaker, I performed some Chinese language Bush Warbler music phrases which I had downloaded earlier from Xeno Canto. Instantly, the hen moved down the closely vegetated slope towards me, growing the frequency of singing in response – and sometimes additionally giving some very loud, barely squeeky churring notes. I used to be in a position to report the music on my telephone, however not these (presumably) aggressive calls. You will want to pay attention at full quantity (finest with head telephones).
Though the hen stayed very largely hidden, there have been brief durations when the music was given from barely extra uncovered perches inside a big bush.
Preliminary impressions, as proven by the digiscope photographs, had been of a reasonably darkish grasshopper warbler, with a really pale throat and barely yellow-washed underparts. It was exhausting to make sure whether or not this color was from mirrored gentle or was real saturation. The supercilium was weak however pretty lengthy and, surprisingly, the hen confirmed apparent recognizing on the higher breast. This recognizing was a little bit weaker and thinner, much less splotchy-looking than anticipated in Baikal Bush Warbler, however was much more apparent than I had anticipated to be proven by Chinese language Bush based mostly on hours of on-line image-browsing in anticipation of encountering one once more (remarkably, nevertheless, the hen appeared nearer in plumage – aside from the supercilium – to a drawing of “varient A” within the on-line Birds of the World by Brian Small than to many of the pictures). The invoice was pretty heavy, with outstanding orange on the decrease mandible – additionally surprising based mostly on on-line accounts.
Thankfully, I managed to take a couple of digiscoped picture…
And even higher – with immense luck and satisfaction – I additionally managed a brief video clip of the hen in music. Please play at full quantity to listen to a brief burst of that incredible music!
If the report is “accepted” (in a nation and not using a formal evaluation course of…) then this presumably turns into the primary adequately-documented report of this species within the Republic of Korea, and presumably on the Korean Peninsula as an entire. As such, the species shall be elevated from Class 3 to Class 1 of the Birds Korea Guidelines throughout the following revision.
This hen follows on from a sight report of a silent, very plain under Chinese language Bush Warbler, additionally on Baengnyeong Island, on Might 25th 2019.
Lastly, based mostly on the mapped distribution of this species proven within the on-line Birds of the World and information in eBird, it appears seemingly that Chinese language Bush Warbler will show to be rather less uncommon on the Korean Peninsula than the Baengnyeong information counsel.
