Bird news from Subhojit Chakladar (with Dr Nial Moores, Andy Lee and Justin Lee)
Peak of the spring migration on this island is a delightful experience. This year however, birds seemed to be in reduced numbers partly due to the wind direction and intensity, and probably partly due to unusually cold temperatures in southern China. Compared to last year, most of the days the diversity of species and numbers seemed much less (185 species observed in 2021 from May 1~9, compared to 172 species this year). There was only one single day where birds were seen moving in significant numbers.
Arriving on the island at around mid day, I met up with NM and we birded the main wetland and the western part of the island. A Pied Avocet and a very unseasonal Tundra Swan were the highlights of the day. A Great Bittern was also heard booming.
The eBird checklist for the day can be found here.
We continued to focus on the western part of the island. 92 species were spotted which would be a good number for any island region in the country but was rather slim pickings by the standard of the island given the time of the year. Swinhoe’s White-eye, which is almost exclusively confined to the outer islands in Korea, were seen in good numbers including a flock of around 35 individuals.
This was the only day where we could observe movements on any significant scale. The morning session was spent almost exclusively in the north-eastern part of the island watching (and at times counting) the moving birds. Good number of buntings were on the move with Yellow-browed Bunting being the majority followed by Little Bunting and Black-faced Bunting. Good numbers of Chinese Grosbeak, Olive-backed Pipit and Eastern Yellow Wagtail were also on the move. Mixed groups of snipes were also seen flying around with some of them settling down in the reedbeds as the wind picked up from the north. All 4 species of snipe that migrate through Korea were observed. Breeding plumaged Chinese Penduline Tit were busy feeding. Single Pacific Golden Plover and White-throated Needletail were also seen in flight, while Japanese Quail was heard singing and later flushed from a grassy trail.
The eBird checklist for the day can be found here.
AL after having arrived the previous day, joined SC and NM. We hit all the major birding spots on the island with close to a 100 species spotted. New birds for the trip was a Wryneck, a couple of Asian Stubtail and a White-shouldered Starling.
An Alpine Leaf Warbler was the highlight of the day. JL arrived by mid day and joined AL and SC for the afternoon session of birding.
The Alpine Leaf Warbler was still hanging out in the same group of trees. However, the highlight of the day was a “golden spectacled warbler” first seen by SC and poorly sound recorded. For the next 4 hours, all members of the team were able to get a visual of the bird though it remained rather out of reach for good photos. At first view, the bird appeared to have a striking head pattern with the grey in the crown being clearly demarcated from the greenish tones of the ear covert. The underparts appeared rather bright yellow. Observed from a distance, the bird seemed to have quite a heavy bill with the lower mandible being almost completely orange. JL (very skillfully) managed to get a few record shots of the bird as it perched momentarily in view amongst the dense tangle of vegetation that it kept to. Even though the shots were distance (and not fully focused given the difficult conditions), the photos still highlight some of the distinct characteristics of the bird. Given that the “golden spectacled warbler” complex can be extremely similar looking, the only reliable way to distinguish them in field is by their calls and songs. Sometimes, it’s easier to “visualize” the call in terms of its spectrograms. Certain species (Pale-legged and Sakhalin Leaf Warbler for example) have similar sounding calls but the frequency range of the calls as seen in the spectrogram don’t overlap.
The call can be visualized as a spectrogram shown below
Based on visual observation alone, the bird could have been any of the 4 species of golden spectacled warblers. However, the call and its frequency distribution helps exclude Alstrom’s Warbler (bisyllabic call) and Bianchi’s Warbler (non-overlapping frequency range). This narrow’s it down to either Grey-crowned Warbler or Martens’s Warbler. Having been a witness to last year’s Martens’s Warbler and analysis of the call that helped establish it’s ID helped eliminate that species as well. This left Grey-crowned Warbler as the only possibility.
Indeed when compared to the call sonogram of recordings of the species by Bram Piot in Laos (XC625377) both the pattern and frequency range seems to match.
The bird was identified as a Grey-crowned Warbler based on this evidence and the photos below.
Incidentally, this species was also reported from nearby Socheong Island by National Migratory Birds Center last year based on visual record only. Our observations add the analysis of the call in addition to the photos making it the 3rd observation of this tricky to separate complex within the span of 1 year.
The eBird checklist of the day can be found here.
With fog blanketing the island for most of the day, birds were greatly reduced in numbers. Despite searching for the presumed Grey-crowned Warbler, we failed to relocate the bird.
With the fog dissipating and winds picking up, birds were on the move once again. However, the strengthening winds made it difficult to bird and also kept birds in cover. A Daurian Starling gave good views while the number of Brown Shrike seemed to have increased a bit. The presumed Grey-crowned Warbler was heard briefly once again in the same area but we didn’t manage to get a visual. New birds for the trip were Sand Martin, Mugimaki Flycatcher, White-breasted Waterhen, Spotted Redshank, Purple Heron, Amur Falcon and Siberian Thrush. Early afternoon, a decent number of snipes were also seen in wet fields with at least 3 different species being identified. Buntings and flycatcher numbers were also picking up in the south-west of the island. The highlight of the day was a presumed Plumbeous Water Redstart seen briefly by SC.
We spent the final day on the island once again focusing on the western part. Highlight of the day was a Yellow-streaked Warbler (heard by NM in the morning and later by AL).
On the ferry back, about a dozen Streaked Shearwater, a heavy set Loon in flight and 2 flocks of Ancient Murrelet.
Thanks to Dr Nial Moores for first suggesting the ID as Grey-crowned Warbler, Dr Jungmoon Ha for very gracefully sharing the analysis of the sonograms and Justin Lee for skillfully capturing the images under rather difficult conditions.