Guest post by Stephan Lorenz
St. Paul Island in the Pribilofs, Alaska is famous for its abundance of nesting seabirds and breeding northern fur seals. Rightly so, since millions of alcids, gulls, and fulmars return to the cliffs of the island each summer to nest, creating a spectacle of streaming auklet flocks, wheeling puffins, and screeching kittiwakes. The island also supports the world’s largest northern fur seal rookeries with approximately 400,000 seals present during the height of the summer breeding season. During a windless day the roars of seals can be heard on almost any point of the island. Add to that the approachable arctic foxes, possible orcas, definite carpets of wildflowers, and a few surprise birds and visitors won’t know where to look first.
Bird watchers flock to the island to catch a glimpse of the action and tally up life birds. One of the stars of the show is the Red-legged Kittiwake, a distinctive gull that is nearly endemic to the Bering Sea. St. Paul Island is one of the most accessible places in the world to see it. Another species high on the wish list of the majority of visiting birders is the Rock Sandpiper, a shorebird that is incredibly abundant on the island. So for a minute, let’s forget about flamboyant Tufted Puffins, comical Crested Auklets, and rare Red-legged Kittiwakes and take a closer look at the shorebirds of St. Paul Island.
In terms of sheer diversity, the shorebirds take the crown on St. Paul with an incredible 64 species recorded on the island within the past three decades. Only four shorebirds nest, whereas the remaining 60 species are either regular spring or fall migrants, rare visitors, or exceptional rarities with only one or two occurrences. The aforementioned Rock Sandpiper is by far the most common breeding shorebird on the island and it is not unusual see several hundred gathered on the salt lagoon, a small bay with productive tidal mudflats. Most birders are thrilled to see their first Rock Sandpiper, especially the large and colorful nominate subspecies found on St. Paul Island. But after seeing Rock Sandpipers on the road, the kelp covered beaches, at the edge of every pond, on the mossy tundra, and even on the top of buildings, most birders ask: “Ok, what else is there?” Well, the simple answer is, “During the right time of year, a lot!”
The volcanic St. Paul Island is a remote speck of land, covering only 43 square miles in the vast Bering Sea, which covers nearly 900,000 square miles. St. Paul Island and the four other Pribilof Islands, most notably slightly smaller St. George Island, offer the only landfall for hundreds of miles. Sitting almost midway between Asia and the North American mainland, shorebirds arrive from either continent and one never knows what shorebird is hiding on the island. About 25 species of shorebirds with mainly Palearctic distributions have been recorded, while the remaining species are either from North America or have circumpolar breeding ranges in the northern hemisphere.
Migrating or lost shorebirds find resting places and nourishment along the beaches and in the wetlands on St. Paul Island. Fortunately for birds and birders alike the island has a variety of shorebird habitats, ranging from tidal mudflats, sandy beaches, rocky shores, a few melt ponds, many freshwater lakes, and a handful of heavily vegetated marshes. A network of roads connects to well-known shorebird hotspots like Salt Lagoon, Pumphouse Lake, Tonki Marshes, and Antone Slough. During migration almost any wet spot or flat area on the tundra can harbor shorebirds. Weather and wind direction play an important role and west or southwest winds usually offer the best chances to spot a rarity from Asia. Inclement weather often grounds birds during migration.
Aside from the abundant Rock Sandpipers the remaining three breeding species are common to uncommon on the island, but reliably found in the right habitat. Red-necked Phalaropes are present in good numbers and almost every pond and lake has a few spinning around. They nest along the edges of the wetlands and are easily observed and photographed. In a few sandy or rocky areas on the island it is possible to find pairs of Semipalmated Plovers, vigorously defending their territories. Least Sandpipers are the rarest nesting shorebird on St. Paul Island with only a handful of birds present during most years and they prefer relatively dry areas with short vegetation among sand dunes. The small population of breeding Least Sandpiper on St. Paul Island lies at the extreme edge of the species’ range.
The diversity of shorebirds is of course greatest during migration. Both spring and fall are excellent, and each season harbors a slightly different mix of shorebirds, although rarities can turn up almost any time between May and September. Spring migration begins as early as the middle of May and continues right through June. Some of the regular spring migrants include Pacific Golden-Plover, Bar-tailed Godwit, Dunlin, and Pectoral Sandpipers which can show up by the handfuls or small flocks. Some of the Bar-tailed Godwits refueling on St. Paul Island may have come from as far away as New Zealand via Asia, an incredible journey over the open Pacific. With great luck a Bristle-thighed Curlew may drop in on St. Paul Island during its migration between Pacific islands and mainland Alaska. Many birders have ticked their lifer Bristle-thighed Curlew on St. Paul’s tundra.
Other Nearctic shorebirds that occur regularly during spring on St. Paul Island include Wandering Tattler, Greater and Lesser Yellowlegs, Whimbrel, Sanderling, and Wilson’s Snipe. Black Oystercatcher, Black-bellied Plover, American Golden-Plover, Solitary Sandpiper, Short-billed and Long-billed Dowitchers are recorded infrequently. Some of the exceptional records of North American shorebirds on St. Paul Island include Killdeer, Upland Sandpiper, Spotted Sandpiper, and Wilson’s Phalarope each with a single occurrence and not to be expected during a short visit.
Most birders of course don’t make the long trek out to St. Paul Island to see a Ruddy Turnstone but instead hope for a rarity or two from Asia. Each spring St. Paul Island plays host to a good number of Palearctic shorebirds. The most regular migrants of Asian origin during spring include Wood Sandpiper, Red-necked Stint, Common Snipe, Common Sandpiper, Ruff, Lesser Sand-Plover, Common Greenshank and Black-tailed Godwit. Several species that are much rarer, but birders can always dream of during migration are Terek Sandpiper, Green Sandpiper, Far Eastern Curlew, Great Knot, and Long-toed Stint.
Fall migration picks up almost as soon as spring migration has waned and it is not uncommon to see southbound shorebirds as early as the end of June and beginning of July. This result in a near constant coming and going of shorebirds passing through St. Paul Island, leaving never a dull moment. Fall migration starts in earnest by the middle of August and continues for about a month with stragglers still moving through by the end of September. The best time to catch up with fall migrants and vagrants from Asia is the last week of August through the first week of September.
Due to the high proportion of juvenile shorebirds on their first southward migration the fall season tends to bring more unusual species and higher diversity of shorebirds than spring. For example some of the rarest shorebird vagrants have been found during the fall season including single records of Marsh Sandpiper, Broad-billed Sandpiper, Spoon-billed Sandpiper, and Pin-tailed and Solitary Snipes. Birders would need a good dose of luck and lots of time spent on the island during the fall to see any of these rare stragglers. There are a handful of species from Asia that are regular visitors, including Sharp-tailed Sandpiper, sometimes in good numbers, Gray-tailed Tattler, almost guaranteed in the fall, and chances for Temminck’s and Little Stints.
Common Ringed Plover, Spotted Redshank, Curlew Sandpiper, and Jack Snipe have been found in a few instances during the fall. The flights of southbound shorebirds are not one-sided of course and many species from the North American continent also stop on St. Paul Island with some of the less common species being Buff-breasted Sandpiper, White-rumped Sandpiper, and Red Knot. Interestingly one of the most common fall migrants is the Ruddy Turnstone, which passes through in ever-increasing flocks of up to several hundred birds.
Birders visiting St. Paul island for a week during the peak of spring or fall migration should not expect to see more than a dozen shorebird species, but it is the unknown or unexpected that makes looking for shorebird so exciting. Each visit will likely turn up one or two species from Asia or possibly more with the right weather system. One never quite knows what to expect on St. Paul Island. For example, Alaska’s second European Golden-Plover during late June was a complete surprise. So bring a scope, as much time as you can spare during either spring or fall, and let’s go searching for shorebirds.
St. Paul Island has a comfortable hotel and good restaurant at the local processing plant. An extensive network of roads allows easy access to the best birding spots. High Lonesome BirdTours has been running trips to St. Paul Island for more than a decade.
If you would like to search for your own shorebird surprise or are looking for one or two Asian vagrant species then join High Lonesome BirdTours during their annual trek to St. Paul Island and let’s see what you can find.
Stephan Lorenz has traveled and birded in literally every corner of the continent, from the Aleutian Islands to Dry Tortugas, from Newfoundland to Baja, and south to the Darian Gap, Panama. He leads birding tours for High Lonesome BirdTours.