I’ve been fortunate enough to have done some birding on islands, namely Amherst Island in Canada, on Kinmen Island and mainland Taiwan, and on some of the small islands off the coast of Korea, namely Eocheong-do (오청도) and Heuksan-do (흑산도). Large islands can often offer the adventurous birder endemic species, found nowhere else on Earth. Smaller island, on the other hand, are havens for birds during migration, and one never knows what will show up.
Unlike the other islands I’ve birded in Korea, Gageo-do (가거도) is about as isolated as a Korean island can get. It’s out in the middle of the Yellow Sea, about 140 kilometers from the nearest mainland port, and has a very small population compared to its size. The island itself is quite rugged, characterized by high, forest-covered mountains in the interior, surrounded by rocky cliffs around the coast. It’s not an easy terrain to navigate on foot, and the trails that do exist are not maintained and barely deserve the name. As compared to Eocheong-do, with its well-kept hiking trails and convenient paved roads, Gageo-do is challenging…but it makes it that much more rewarding.
Island birding in Korea means pelagic birding, as the islands are only accessible by ferry. Depending on the destination, this rare opportunity to observed the ocean’s unsung avian wonders can be thrilling or a complete miss. The ferry to Gageo-do takes between 4 and 5 hours to reach the island, making a few stops at other islands along the way. However, unlike the ferry to Eocheong-do, passengers are not permitted to go outside of the cabin throughout the trip, so all birding must be done looking through the window.
Nevertheless, the sea was surprisingly calm and the skies were clear. At about the one hour mark, we came onto several groups of red-necked phalaropes out in the ocean. These shorebirds spend the breeding season on land in the northern latitudes, but retreat to the open ocean for the winter. It wasn’t until we were nearing Gageo-do that I began to see my first pelagic species. Gageo-do has a breeding colony of Swinhoe’s storm petrels, which nest on the surrounding islets. There were dozens of groups of threes and fours, flying quickly from the path of our ferry. Hidden among these small birds were three unusual specimens. Swinhoe’s storm petrels are bat-like in appearance, and have dark plumage all over their bodies. So imagine my surprise when I picked out three birds showing bright white rump patches as they evaded the ferry. Reviewing my copy of Onley & Scofield’s Albatrosses, Petrels & Shearwaters of the World, I narrowed it down to either Leach’s storm petrel or (more likely) band-rumped storm petrel. Reviewing my observations, I decided on Band-rumped, as the birds I observed did not have the forked tail common in Leach’s. I doubt this is the first recorded sighting of this species in Korean waters, but it is nonetheless an exceedingly rare occurrence. Both A Field Guide to the Birds of Korea and the Birds Korea Checklist for the Republic of Korea only list Swinhoe’s storm petrel as occurring in Korean waters; even the checklists on Avibase fail to mention any other storm petrel species. If only I had been able to get a photo for confirmation…
When we finally arrived at the island, my first encounters were with the resident species. Blue rock thrushes were plentiful, and the prevalence of first-year birds indicate there was a successful breeding season on the island. The marina held dozens of grey herons and smaller numbers of great egret and little egret. The village of Gageodo-ri was patrolled by a pair of common kestrels, which would put in an appearance everyday of my trip. Elsewhere around the village were numerous light-vented bulbuls; these rare breeders actually outnumbered the brown-eared bulbuls which are far more common on the mainland. And flitting about the harbors were numerous wagtails, including grey, white, and eastern yellow wagtails.
But it was the migrants that I was interested in. There isn’t much in the way of shorebird habitat at Gageo-do. The beaches that are there are rocky and the sand is replaced by smooth pebbles. However, a few migrant shorebirds were around, including singles of Pacific golden plover, red-necked stint, long-toed stint, and several wood sandpipers that could be found on the grassy common area at the center of Gageodo-ri. Cryptic Latham’s snipes were flushed from their hiding places in the tall sedges around Gageodo-ri and Hangri-maeul.
I was hoping for some migrant warblers and flycatchers, which should be moving through in good numbers. The few trails that I had located around Gageodo-ri were too overgrown to bird effectively – I spent more time avoiding thorns and watching my footing than watching the birds around me. Luckily, there are two roads that traverse the island, connecting the main village of Gageodo-ri to the small hamlets of Hangri-maeul and Sam-gu. Most of the migrant passerines could be found along these roads, where the edges of mountain forests met the rocky coastline.
The most common bird along these roads, besides the blue rock-thrushes, were grey-streaked flycatchers. I am not sure whether this species breeds on the island; I usually found them in groups of three or more, flitting along the roads and into the air as they hawked insects and dragonflies. Migrant warblers could also be found along the roadsides. I didn’t find many warblers in large numbers, but there was definitely a good variety of species. Dusky warblers were probably the most numerous; although I rarely actually saw them, their distinctive chip note could be heard frequently along the road. Eastern crowned leaf warblers and yellow-browed warblers were present in smaller numbers, and I had a brief glimpse of a brightly colored Pallas’s leaf warbler. However, the best Old World warbler (and the best bird of the entire trip!) was Middendorff’s grasshopper warbler, a drab brownish warbler that I located twice near the village of Gageodo-ri.
Although it isn’t much to look at, the Middendorff’s was officially my 700th species!
The most numerous bird of all, however, was the Japanese white-eye. These small greenish birds were literally dripping off the leaves. I would often have to sift through large flocks of white-eyes just to spot that one non-white-eye.
The island also hosted a few predators as well. In addition to the pair of kestrels that patrolled the skies above the main village, at least two peregrine falcons were also making use of the thermals over the mountainous interior. Shrikes were also fairly common on the island, with three species present. Brown shrikes are often found on the islands offshore around Korea; I found one on Eocheong-do during the spring migration. On Gageo-do there were two brown shrikes, each on a different side of the island. A single juvenile bull-headed shrike indicated that there was likely a breeding pair of adults somewhere on the island, even though they remained unseen during my stay. The big surprise was not one but two long-tailed shrikes, again on either side of the island. These shrikes are quite common in China and Taiwan, but almost entirely absent from Korea. Occasional records do crop up on some of the islands, but overall it is quite a rare bird for the country.
The four days on Gageo-do were a great way to kick off the fall migration. There was a good variety of resident and migrant species, and I was treated to some rarer species that I can’t find on the mainland. In total I saw just over 50 species, and picked up 4 life birds, including #700!