Some Field Notes on the Breeding of the Greater Kelp Goose PETER GLADSTONE and CHARLES MARTELL

Breeding of the Greater Kelp Goose 25 Some field notes on the breeding of the Greater Kelp Goose PETER GLADSTONE and CHARLES MARTELL Introduction Furthermore, the eggs of various species Together we spent from November 1964 of penguin are more easily collected in to March 1965 in the Falkland Islands, large numbers—and fresh. South Atlantic, with the purpose of study We had evidence that the breeding ing the Greater or Falkland Kelp Goose population was in many places at or near Chloëphaga hybrida malvinarum. It was saturation with a reserve of non-breeding also possible to make observations on the birds. When one female died egg-bound majority of other species of birds found another arrived in the territory and paired in these islands. with the gander within twelve hours. We arrived separately in the islands on When a pair with young were washed 4th November transported as guests of from their territory by a storm, a new the Royal Navy. Peter Gladstone travelled pair moved in within a few days. Apart in H.M.S. Protector, the Ice Patrol Ves from the area immediately around the sel. Charles Martell travelled down the town of Port Stanley we found no suit west coast of South America in H.M.S. able territory which was unoccupied. It Tiger and from South America to Port is almost certainly the specialized Stanley in the tanker R.F.A. Wave Chief. demands of the bird’s ecology which keep We arrived at our first camp on 12th the population comparatively low. November, the day the first Kelp goslings of the season left their nests. Habitat Our chief area of study was at Port The Kelp Goose feeds almost exclusively San Carlos on the west side of East on green algae on the shore. Very occa Island, particularly on narrow Big Island sionally birds feed on short grass and, ( l i miles long), named on maps as Fan probably more regularly, on the berries ning Island, but not so known locally, of ‘ Diddle-dee ’ Empetrum rubrum in near Fanning Head. We also made obser the austral autumn, again nearly always vations round the coast of Port San Car close to the shore. los, which covers an area about the same The breeding territories are found on as the Isle of Wight, on the north end rocky shores where the fine green algae, of Great Island in the Falkland Sound, like Enteromorpha, grow in the inter on West Point Island, Carcass Island and tidal zone, on comparatively calm coasts. New Island to the west. Thus breeding Kelp Geese are found in We were probably lucky in visiting two bays, in sheltered sounds, in areas where areas where the Kelp Goose is particularly there is a wide shallow underwater shelf, abundant, Great Island and Fanning or, frequently, where the shore is pro Island. Roddy Napier, a leading ornitho tected from the main waves by the blan logist who has spent his life in the islands keting effect of the vast kelp seaweed and knows them well, told us he knew Porphyra umbilicalis. This grows to of no other areas with so high a popula great length and the fronds often cover tion. the surface of large off-shore areas. The In spite of the fourpenny bounty on birds can even find territories on the the bills of other ‘ geese ’ the Kelp Geese north coast, where kelp abounds, though suffer little from persecution by man. there is no land between there and the The bills are not acceptable for the British Isles and the sea is seldom calm. bounty and are easily recognised, the It has been recorded by Boyson (1924) female’s being pink and the male’s having and by Cobb (1933), and frequently re a white spot on the upper mandible—a peated, that the birds feed on this sea fact that may well have saved the bird weed. This is certainly not the case. from near extinction. Other factors Their basic requirements appeared to be favouring their survival are that the eggs at least seven yards width of intertidal are laid rather later than those of the zone (tides average seven feet in height) other Chloëphaga species, at a time when with enough algal growth to make it lamb marking and castrating keep the appear greenish, rocks which will not local inhabitants busy; the nests are move in storms and so destroy the algae, usually less accessible to human settle some nest cover close to the high tide ments than tnose of the Greater Magel mark, and shelter or a blanket of kelp. lan Goose Chloëphaga picta leucoptera During the breeding season territories and the eggs are said to be foul-tasting. are closely defended by both sexes, the 26 Wildfowl male being seen to chase away intruding are a slightly creamy white. The shape males and females, and the female other varies very considerably, some being long females. The size of the territories varies and thin but the majority tending to a considerably with local conditions. A blunter ovoid. single pair may be alone in miles of coast The clutch sizes of 44 nests found in line because there is only one small bay which laying was complete and where with the necessary conditions. In other there was nothing to suggest disturbance places nests may be as little as fifty yards or that they were second clutches were apart, though seldom does a territory as follows: cover less than a hundred yards of shore Clutch size 6 5 4 3 line. No. of nests 21 17 5 1 Nests We heard that a clutch of eight has We found 56 nests in use and a number been seen but could not get details. which had been in use before we dis Clutches of seven eggs do appear occa covered them, or were from previous sionally. Mr. Napier found one on West years. Some of the latter were close to Point Island in 1957 but he considered present ones, suggesting traditional attach it unusual. Pettingill (1955) records one ment to sites. Indeed in some cases we on Kidney Island. Boyson (1924) recorded found several layers of old down and clutch size as 2 to 4. This is suggested as grass, one on top of the other. the normal size for the Lesser Kelp Goose Nest cover varied from a dense cover Chloëphaga hybrida hybrida on off-shore of ten-foot high tussac grass Poa flabel islands in Chile by Johnson (1955). We lata to planks of old sailing ships (which found two newly-hatched broods of littered the coast and provided much of seven young after a storm in territories our fuel for cooking and for heating hot- where neighbouring adults were missing water bottles—for our tame goslings). and there may have been amalgamation, However, with practice, we could usually also two broods of seven well-grown pick out where the nest would be in any young in February on New Island. Mr. given territory. It would be partially hid Napier saw a brood of nine on Dunbar den, but allowing the highly cryptic Island in 1957. female to have a view out. Usually the We measured the eggs of 10 clutches, bird could walk at least a couple of yards 48 in all, and found the average to be to the nest, though she might have to 82.5 X 55.6 mm. (ranges 78-89 X 53-58). fly direct to a small hole in the vegeta One exceptional egg from an otherwise tion. All nests save one were within ten normal clutch measured 105 X 65 mm. yards of the high tide line, and most were Schcnwetter (1960-1) gave the measure closer than that. The exception was 100 ments of 27 eggs as 83.5 X 54.0 mm. yards from the shore of Great Island, (75-91 X 53-58). Boyson (1924) gave against the first bit of cover inland from ranges of 80-84 X 55-58 mm. an otherwise perfect feeding territory. When we arrived on 4th November Where available a ledge amongst stunted most clutches were well incubated and tussac grass four to eight feet up a little we did not get a chance to discover the cliff was preferred. On Great Island, incubation period. (Delacour (1954) gives where sheep have exterminated the tus it as 30 days.) From the first sign of sac grass except on such cliffs, ground chipping, individual eggs hatched within nests were beside drift-wood, an out 12 to 48 hours and the young normally standing boulder, amongst Empetrum, or left the nest together some hours after in the coarse white grass Cortaderis the last eggs hatched. In the majority of pilosa with which most of the islands cases this was about 48 hours after we are covered. had found the first egg chipping, but The scrape was lined with any avail sometimes considerably longer. Cobb able vegetable matter and down was (1937) states ‘ . young leave the nest added when the last egg was laid and one by one as they hatch . ’ and ‘ . incubation started. Where incubation was but the Kelp Ganders just sit about or advanced there was normally a consider feed, and do not appear to care if they able quantity of grey down and the eggs lose the lot or not. This is perhaps a were covered with this when the female good thing, or the place would become left to feed. The white male does not smothered in Kelp Geese ’. We saw one take any part in incubation and has no newly-hatched young tended carefully by brood patches.

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