Late September saw a major influx of migrant birds to Bird Island. As expected from previous experience, shorebirds predominated among these early arrivals. Most breed at high latitudes and those that arrive in Seychelles probably nest in northern Asia. There, climatic conditions force them to have a short breeding season, after which they migrate south early to escape the return of inclement conditions.
On Bird island small numbers (believed to be less than ten of each) of Turnstones, Curlew Sandpipers and Whimbrels spent the northern summer on the island, probably young birds that failed to reach breeding condition. In late September, however, numbers increased sharply, leading to estimated populations of more than 250 Turnstones, at least 50 Curlew Sandpipers and similar numbers of Grey Plovers and Whimbrels. The last of these made their presence felt over the whole island with their loud repeated “piu piu piu piu piu piu” calls whenever disturbed. Many of the Turnstones retained some of their spectacular breeding plumage of bright chestnut, black and white, with bright yellow-orange legs, while most Curlew Sandpipers had moulted out of their rusty-red breeding plumage and arrived on the island almost entirely grey and white, like heir offspring. In my blog of 25 August, I mentioned a Grey Plover that had arrived in partial breeding plumage, and which also carried rings on its legs. This bird is still present but has now moulted its black breast and scaly black-and-white back into its less spectacular winter dress. This bird has now been joined by other Grey Plovers in various stages of moult, and by two Asiatic Golden Plovers that retain their black bellies and golden-coloured backs.
The highlight of the month’s arrivals, however, was the first land bird of the northern autumn, on 27 September, and first seen and photographed by a German tourist and photographer, Olaf Zesch, as the bird foraged in rough ground in front of the hotel restaurant. Christine and I found it that evening feeding on the side of the airstrip, were it allowed close approach as it concentrated on replenishing the energy lost in reaching Bird Island. The bird was a Corncrake, a small member of the rail family that outwardly does not seem to be built for long-distance migration. According to the Seychelles Bird Record Committee, this was only the fifth time that the species had been seen in Seychelles; it was the second occurrence on Bird Island however, where I had recorded the first Seychelles record in 1973!
The arrival of northern migrants on Bird Island is always exciting, especially in the knowledge that these birds must have travelled over at least 1500 kilometres of open ocean to reach the island, but it does not always have a happy ending. On 28 September we found a Greenshank close to the hotel. It allowed me to approach closely and pick it up; it was so weak. It was totally emaciated, with breast muscles severely atrophied and was clearly not going to survive.
Each northern autumn several birds are seen to arrive in this condition, having used so much energy on the migratory flight. Most die on the island but few corpses are found – the many land crabs are efficient scavengers. The first Corncrake that I found in 1973 turned out to be one of these casualties. It was so weak that I was able to catch it by hand. When I weighed it, it proved to be less than half of the weight of a healthy bird and stood no chance of survival. This year’s bird was in much better shape and will hopefully survive to return to its northern breeding grounds next year.