Autumn migration on Ishigaki Island is winding down, but an out-of-season typhoon drove in a greater variety of birds.
A Pied Avocet arrived at a paddy field near the town centre.
A work trip to Yonaguni Island gave me a little time for birding. I had hoped for rarities like the Chestnut-winged Cuckoo and Grey-faced Buzzard from the previous year, but it didn't quite work out that way. Even so, I got to see a flock of Eurasian Siskins — a species you rarely encounter on Ishigaki — so it was an enjoyable trip.
My first Naumann's Thrush of the season turned out to be on Yonaguni Island.
A Crested Serpent Eagle was eating a toxic Cane Toad. Below I reproduce the article I wrote on Crested Serpent Eagle venom resistance, published in the newspaper on 19 July.
Cane Toads were introduced to Ishigaki Island around 1978 to control sugarcane pests. They secrete a potent cardiotoxic steroid, bufadienolide, from their skin — a toxin that can stop the heart. There are confirmed cases of the native Sakishima Rat Snake dying after eating one. The Crested Serpent Eagle, on the other hand, shows no ill effects even after consuming the toad's highly toxic skin. Local birdwatchers had long noticed this, but no scientific explanation had been established.
The research team analysed tissue samples from 24 Crested Serpent Eagles that had died from accidents or illness between 2020 and 2023. Focusing on an enzyme responsible for ion transport across cell membranes — the target of the toxin — they discovered an amino-acid substitution in a key region associated with venom resistance, known as the Q111E mutation. This mutation appears to prevent the toad's toxin from binding to the enzyme, neutralising its effects. Similar mutations have been found in snakes that prey on toads and in birds that eat toxic butterflies, and the finding is regarded as an example of convergent evolution — the process by which unrelated lineages independently arrive at similar traits through different evolutionary paths in different places.
Strikingly, Crested Serpent Eagles on Iriomote Island — where Cane Toads have not established — and even a subspecies of Crested Serpent Eagle on the distant Indonesian island of Simeulue carry the same resistance gene. Genetic analysis suggests the trait has been preserved since around the time the Crested Serpent Eagle diverged as a species, long before any alien species was introduced. Tobe of Kyoto University's Wildlife Research Center explains: "The venom resistance of the Crested Serpent Eagle is not a recent adaptation to environmental change, but an ancient trait inherited from its ancestors — one that has, by coincidence, also helped to mitigate the physiological impact of an invasive species. It is a rare example of that."
The study also confirmed similar resistance gene mutations in snake eagles closely related to the Crested Serpent Eagle. There are reports that the Black-chested Snake Eagle in South Africa showed no health problems after being fed toxic toads in captivity for 12 months, suggesting this ability may be characteristic of the group as a whole. Meanwhile, on Japan's Ogasawara Islands, Eastern Buzzards have been recorded preying on the same Cane Toad, but no clear venom-resistance mutation was found in their genes, pointing to the possibility that they cope through a different mechanism.
The study also found that the Crested Serpent Eagle populations on Ishigaki and Iriomote islands are genetically distinct. Despite a separation of only about 20 kilometres, movement of individuals between the two islands appears to be almost nonexistent — a finding the team says "suggests that the Iriomote and Ishigaki populations should be considered independent conservation units." The research demonstrates that an organism's "hidden abilities" may play an important role in responding to environmental change. While the findings offer a significant new perspective for biodiversity conservation, Tobe also sounds a note of caution: "The fact that the eagle is making use of the invasive species does not mean the invasive species problem can be ignored. Once the Crested Serpent Eagle is preying on them, the toads are being incorporated into the ecosystem, and there is a risk of further disrupting the overall balance." As the global impact of invasive species on ecosystems becomes an ever greater concern, this discovery — shining a light on the unexpected adaptive capacity of native species — underscores both the depth of evolutionary processes and the complexity of conservation strategy.
A Crested Serpent Eagle eating a Cane Toad. As the research papers suggest, the toxin seems to pose no problem for it.
A Crested Serpent Eagle rescued in Nagura in September 2024 has been released back into the wild. It had suffered serious injuries — a broken right wing, a broken left leg, and bleeding from the mouth — but after 18 months of treatment and rehabilitation, it has finally been able to return to nature.
For identification purposes, it is fitted with a ring on the right leg stamped with a red "4". This data is valuable for Crested Serpent Eagle conservation efforts, so please get in touch if you spot it.
A Crested Serpent Eagle being released by staff from Ishigaki Yaima Village, which has a rehabilitation facility.
A Black-headed Bunting turned up after a long absence. It was very likely the same individual I briefly glimpsed in the same paddy field about a week ago. It was mixed in with a flock of several hundred Eurasian Tree Sparrows.
A Forest Wagtail appeared on the usual forest road — the sixth individual this season. Arriving this late in the year, there is a good chance it will winter here. Last year one wintered at the same spot. Once they settle into wintering mode, though, they tend to stay deep inside the forest and become harder to observe.
Arctic Warblers have been showing up since early October. Birds fresh in from migration are often in small flocks, but now they have spread across the island and each is holding a small territory. Many individuals will stay through to spring. Come April, they form flocks again in preparation for the northward journey, and some begin to sing.
Brambling have also appeared. They joined up with Eurasian Tree Sparrow flocks and were feeding on second-crop rice grain in the paddies.
White-shouldered Starlings — a few birds — were mixed into a flock of several tens of White-cheeked Starlings, along with around 20 Common Starlings. The wintering White-shouldered Starling population on the island is sizeable in its own right, and flocks of several tens are regularly seen in parks and the like.
At this time of year, snipe are mostly Common Snipe, but among a flock of ten-odd I found just two Swinhoe's Snipe. I expect them to disappear once the second-crop rice harvest gets under way. Other waders lingering in the paddies include Common Redshank, Common Greenshank, Marsh Sandpiper, Black-winged Stilt, Wood Sandpiper, Green Sandpiper, Common Sandpiper, and Long-toed Stint.
Ducks are increasing too — I recorded my first Mallard of the season on Ishigaki. Mallard used to be quite scarce on Ishigaki and Okinawa, but the numbers being seen seem to grow a little more each year.
A Black-headed Bunting standing out prominently among a flock of Eurasian Tree Sparrows. It was constantly harassing them….
Two Pied Avocets have been present for several days. A flock of Black-faced Spoonbills and Eurasian Spoonbills, Bar-tailed Godwit, and Garganey have been staying a long time. Wintering Eurasian Teal and Northern Shoveler are also steadily building up.
Two Pied Avocets with zero wariness are staying in the area.
Pechora Pipits have arrived again this season, in small numbers. Last year I found two among a flock of Red-throated Pipits. This time I noticed them by their calls overhead, and after a flock of five dropped into the paddy I searched and found two individuals. ^^
While looking for the Pechora Pipits, a Brown-cheeked Rail also appeared. It was a brief encounter — the bird was very wary — but a welcome one.
Ducks are growing in number and variety; I had my first Northern Shoveler of the season on this day. By the time the ducks arrive, both Pin-tailed Snipe and Swinhoe's Snipe have already moved on, leaving large numbers of Common Snipe behind.
The Javan Pond Heron that arrived in late July was still present. At peak there were three, but now only one remains. It should stay until around February, being in wintering mode.
Elsewhere, I noted Masked Bunting and Yellow Bittern. A Pied Avocet apparently made its way into the grounds of a facility where a friend of mine works.
Paddyfield Pipit seen again this season.
Red Collared Doves have turned up at various spots around the island. The largest flock I saw was nine birds, roughly half male and half female.
Wintering Common Kestrels are also increasing, and a nearby water area had growing numbers of Little Grebe and Eurasian Coot — these too will be wintering on Ishigaki.
The Crested Serpent Eagles have finished breeding and are now easier to find in open habitats such as paddy fields.
A male Pale-backed Pigeon. Looking worn out after a spell of rough weather.
Ducks have started arriving on Ishigaki-jima. Eurasian Teal and Garganey — the first of the season — are increasing. The first Tufted Duck of the season was also in a drainage ditch on farmland.
In the rice paddies, the snipe are now down to Common Snipe only. Black-winged Stilt, Common Greenshank, Marsh Sandpiper, Long-toed Stint, Wood Sandpiper, Green Sandpiper, and Common Sandpiper are all still present. Eastern Yellow Wagtails are turning up here and there but numbers aren't building much. Could the heat be slowing their movement?
Whiskered Terns have been lingering along the river near my house.
Garganey, juvenile male. Fairly approachable.
Pin-tailed Snipe have dropped sharply and the fields are now full of Common Snipe. A few Swinhoe's Snipe are still hanging on. Last year the final Pin-tailed Snipe of the autumn migration was recorded on 18 October. I wonder how long they'll be around this season. I don't think the 2024 birds will overwinter, but Pin-tailed Snipe and Swinhoe's Snipe were confirmed in February. I know it's getting ahead of myself, but I'd love to find overwintering birds in 2026.
I went back to check on the Grey-faced Buzzards again today after yesterday's visit, but things were quiet — it felt like the main push had already moved through the day before… ^^; At this time of year my daily snipe rounds make it hard to get out and watch the Chinese Sparrowhawk and Grey-faced Buzzard migration properly…
A juvenile Pin-tailed Snipe. This might turn out to be my last Pin-tailed Snipe of the season.
I photographed Red-throated Pipit and Arctic Warbler for the first time this season. I had already confirmed both by sight and call a few days ago.
On this day, more than 8,500 Grey-faced Buzzards were counted — a record — but by the time I arrived during a break from work the peak had already passed and I ended up counting only around 200…
A small flock of about ten Red-throated Pipits arrived. One or two Buff-bellied Pipits appeared to be mixed in, but I couldn't get a photo.
We held the Ishigaki-jima Snipe Camp again this season — five years running, thanks to everyone who has taken part. This time there was one participant. We met at 9 a.m. and spent the day watching snipe until around 4 p.m.
Because we held it about a month later than usual, Pin-tailed Snipe numbers were low — only 2 individuals out of several dozen snipe seen. Swinhoe's Snipe were the most numerous and are at peak, so almost all were juveniles. Common Snipe juveniles are now arriving to join the adults, and numbers should peak soon.
Please also have a look at past Ishigaki-jima Snipe Camps. The next one is planned for spring next year. Come and sharpen your skills at separating Pin-tailed Snipe from Swinhoe's Snipe. ^^
First Grey-tailed Tattler juvenile of the season, Great Knot, and Temminck's Stint juvenile were all seen. Common Greenshank juveniles are increasing. While watching the snipe, a Ruddy-breasted Crake appeared — the first in a while.
A Pin-tailed Snipe finally squeezed out after scanning through dozens of snipe.
While watching a group of around ten Swinhoe's Snipes, a snipe appeared in the grass. It was a typical Pin-tailed Snipe juvenile, so I followed it with binoculars hoping to get a look at the tail feathers — and it bathed rather sooner than I expected. ^^
A group of around ten Whiskered Terns — adults and juveniles — arrived. Among the snipe, Common Snipe numbers are up while Pin-tailed Snipe have decreased.
Long-toed Stint, Wood Sandpiper, Common Greenshank, and Marsh Sandpiper are also present in good numbers.
White-winged Tern juvenile. Perhaps due to the lack of typhoons, no large flocks have appeared this season.
The Common Ringed Plover that appeared in early September was still present — three weeks into its stay. It seems to be moving widely around the island, between the rice paddies and the coast. The Javan Pond Heron is also on an extended visit.
The first Pacific Golden Plover juvenile of the season has also arrived. When these appear, the wader migration is in its final stages.
Pin-tailed Snipe and Swinhoe's Snipe numbers fluctuate daily as residents mix with birds moving through.
A Kentish Plover still present.
The first Common Greenshank and Ruff juvenile of the season arrived. Also still present: Pin-tailed Snipe, Swinhoe's Snipe, Common Snipe, Black-winged Stilt, Long-toed Stint, Red-necked Stint, and Marsh Sandpiper.
The first Common Greenshank of the season.
Following last week's visit when I was able to see a Willow Warbler, I was on Yonaguni-jima again for work. I made sure to fit in some birding between assignments. ^^
Nothing as noteworthy as last time, but it was striking to find small groups of Black Paradise Flycatchers all over the place. I was of course hoping for Indian Paradise Flycatcher too, but unfortunately didn't come across any likely candidates…
Discovered a flock of Japanese Paradise Flycatchers beside the park car park.
The day before, I had found only one Pin-tailed Snipe on my usual paddy rounds, but numbers were up today. It doesn't feel like a second wave — more likely they were simply hiding in the grass and I missed them.
Pin-tailed Snipe juvenile.
By the second half of September, Ruddy Kingfisher numbers are starting to drop. Even so, on this day I confirmed 9 individuals at 3 locations.
A Ruddy Kingfisher on the forest track. An unwarry individual — I suspect the same bird has been returning for several years running.
By mid-September the Pin-tailed Snipe numbers are falling and Swinhoe's Snipe are coming to dominate. After this, a second wave of Pin-tailed Snipe is expected.
Juvenile Red-necked Stints have started arriving. Long-toed Stint, Common Greenshank, Dunlin, and Superb Lyrebird are also present.
The only Pin-tailed Snipe of the day was at the far end of the paddy field — a long way off….
Birding in the gaps between work assignments on Yonaguni Island. As I cruised the forest road with a sense that autumn migration was well and truly getting under way, I spotted a fig tree that birds were gathering in. While watching a flock of Warbling White-eyes, a yellow warbler flew into my field of view. I got it in the binoculars — it was a Willow Warbler!! It was moving from branch to branch, apparently picking off small insects.
I also had first records for the trip of Chinese Sparrowhawk, Oriental Dollarbird, Dark-sided Flycatcher, Asian Brown Flycatcher, Grey-streaked Flycatcher, Garganey, Common Snipe, and White-shouldered Starling. Yonaguni Island delivers, as always. ^^
Arctic Warbler makes an appearance. It stands out clearly — obviously different from the other Japanese leaf warblers.