A DAY AMONG THE MIGRANTS

New Zealand Listener, Volume 14, Issue 355, 12 April 1946, Page 30

A DAY AMONG THE MIGRANTS

(Written for "The Listener" by DR.

R. A.

FALLA

ruary, and through the month of March, there is a good deal of excitement and activity amongst thousands of birds which are preparing for the annual migration to the Northern Hemisphere, It passes unnoticed in the main because the birds themselves are inconspicuous and drably coloured, and their haunts are tidal mudflats, estuaries, and brackish lagoonsareas which are otherwise deserted. The name of one of them, the Godwit, has become somewhat legendary and most books about New Zealand make some reference to the annual migration of this bird to and from Siberia. Most New Zealanders have at least read something of this marvellous flight, of the Maori legends connected with it, and the various theories which seek to explain why the birds migrate at all and by what means they find their way over such amazing distances. At the moment it is not my intention to deal with, this aspect of the story, but merely .to describe a field day spent on Lake Ellesmere, which is one of the South Island feeding grounds much frequented, not only by the visiting waders from Siberia, but by many resident native water birds as well. The lake itself, as most people know, is a very shallow but extensive lagoon south of Banks Peninsula, separated from the sea by a narrow bank of sand and piled-up shingle. At irregular intervals in the past the sea has burst through at the southern end, often enough to give a permanent brackish quality to the water of the lake. For the benefit of the surrounding farmland it has also been customary to make an artificial channel at the outlet from time to time, but this always closes up again. Normally the tides have no effect, but on such a vast expanse of shallow water107 square miles-the wind that happens the end of Feb-

to be blowing makes amazing differences to the levels. Thus a nortlierly wind will inundate many acres of flat at the southern end and conversely a southerly will flood the northern areas about Motukarara and. Kaituna. It is this fluctuating of the water that provides such a remarkable feeding ground for birds that can swim, paddle, or wade. It means, of course, that the naturalist who plans to pay a visit to observe birds needs to be a practical weather prophet with a good knowledge of the peculiar habits of the lake as well as of the ways of the birds. A Lake in February I was fortunate on a recent trip late in February to have the expert guidance of E. F. Stead, whose long acquaintance with the district and skill as a naturalist have made him our foremost authority on migratory shore birds. I may say that I have made many previous expeditions to the lake with disappointing results, as often as not striking the wrong part of the lake shore for the particular weather at the time. The last trip was made with no, indication of wind from anywhere, but the northern end of the lake was decided on. It was a bright morning and very still, and when we arrived on the flats birds could be seen in all directions on exposed spits and shallow bays. Most of them, however, were very far distant, and as the air was still their cries could be faintly heard. Black swans, Canadian geese, and numerous duck provided most of the deeper sounds; there was plenty of the raucous screaming of gulls, faint yelping of stilts, and closer at hand the chip-chipping note of numerous Banded Dotterel. But we were not out to look at the birds that can be seen all the year round. Time was getting short fot observing the migrants which leave in March, and on such an ideal feeding ground we ‘had hopes of seeing a number busy feeding

OPPOSITE: Photograph of museum exhibits of male and female (on left) Godwit, a migratory wading bird mentioned in this article in preparation for the journey. It appeared at first that, if they were there at all, they must be very busy feeding, for none was to be seen on the wing. However, it was not long before Mr. Stead’s experienced eye lighted on a small grey and white bird feeding with a flock of Dotterel. It was of the same size, and in the distance nothing but a slight difference in its method of running had enabled him to single it out. A little careful manoeuvring with field glasses

soon enabled us to distinguish the stranger as a Curlew Sandpiper. This was a good start, for the Curlew Sandpiper is one of the less common of the Siberian visitors. It is hardly bigger than a sparrow but of very different build, with a slender beak and spindly legs. It looks an absurdly delicate bird to make a journey twice annually from one end of. the world to the other, but some of these travellers, like the Little Stints, are even smaller. Weather Wisdom We were still scanning the lake and shore for more birds when Mr. Stead turned his attention to clouds. There seemed to be no visible change in the weather, but he detected a faint greyish smudge in the south-east, and predicted that within less than 20 minutes we should see all the birds we wanted to without moving from the spot. This seemed to me rather unlikely, but in a very short time a southerly was advancing on a broad front, In addition to the gathering low cloud there was a deep roar as the wind came across the lake, and very soon we could see birds of all kinds being picked up and swept along in front of it like so many scraps of paper. By the time the wind reached us they began to hurtle past in some confusion, much too fast indeed for us to distinguish any but the more obvious

birds like swans, ducks, gulls, and stilts. The little grey and white waders that were mixed up with them might have been anything as they flashed past. It turned out, however, that this was only a temporary retreat. It takes more than a strong wind to. keep birds off their feeding ground, and the lake itself was beginning to move and spread into new areas and form a new shoreline. As it ‘did so the birds began to come back. They came back in small parties, usually one kind at a time. The wind being now steady, the birds flew low, and alighted to rest at frequent intervals. It was from this process that we were able to identify many more of the migrants. Birds Prepare for Spring First three Godwits came over, flying ‘strongly, and passed on. The stocky little Knot, also flying strongly, was the next one seen, and then some Golden Plover, all of these in their winter plumage and not very conspicuously marked. The bird of more striking pattern that came next was the Turnstone. By now we had been lucky enough to see all of the more regular migrants that seem to come every year in fair numbers, but we were still optimistic enough to hope for more of the rare ones. Before we left one of them came along. A party of very trim little birds, six, or seven of them, alighted to feed for a few minutes in a flooded patch of salicornia. They were Siberian Sharptailed Sandpipers, and by the time we had identified them they were already on the wing again. One of them, in richer plumage than the rest, gave’ a trilling call as it passed and hovered in the air like a skylark for a few seconds. This little ceremony and: the brilliant plumage showed that it was an adult bird commencing that train of behaviour that ends on the nesting-ground in North Siberia some two months later. Although it was auturhn here, these birds that belong to the other end of the world were already putting on their spring plumage and practising the rather pretty display with® which they enliven the nesting season on the Siberian tundra.