5) Bingham M. and Mejias E. (1999) Penguins of the Magellan Region. Scientia Marina Vol:63, Supl. 1: 485-493
6) Bingham, M. (1999) Field Guide to Birds of the Falkland Islands.
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The Distribution, Abundance and Population Trends of Gentoo, Rockhopper and King Penguins at the Falkland Islands
by Mike Bingham. Published 1998 in ORYX 32(3): 223-32.
SUMMARY
The Falkland Islands are a globally important breeding location for seabirds, including penguins. The total breeding populations of three of the four main penguin species present in the Falklands were censused in the austral summer of 1995/96. The results for gentoo and rockhopper penguins suggest declines of about 43% and 90% respectively since a similar census in 1932/33. Recent monitoring studies suggest that these declines are still continuing; research to investigate causes (likely to reflect changes in the marine, rather than terrestrial environment) is a high priority. In contrast king penguin populations, currently c.400 pairs, have increased steadily, by 700% since 1980/81, in line with world-wide trends for this species.
INTRODUCTION
The Falkland Islands lie in the South West Atlantic, approximately 450 km. north east of the southern tip of South America. The archipelago is made up of two main islands, and several hundred smaller islands, which are home to large numbers of breeding seabirds, including penguins. The Falkland Islands have the world's largest breeding population of rockhopper penguins (Eudyptes chrysocome chrysocome), and the second largest population of gentoo penguins (Pygoscelis papua) (Croxall et al. 1984).
Data gathered from breeding colonies around the Falklands during the past 10 years, suggested a decline in the breeding population of gentoo and rockhopper penguins (Bingham 1995). The only comprehensive island-wide population census for these species was in 1932/33; a repeat census was needed to confirm whether declines were occurring throughout the islands, and to estimate their magnitude. In addition, the census would establish comprehensive baseline data to complement current monitoring studies. The imminent exploration for oil in Falklands waters, makes the establishment of baseline data for these species particularly important, because of their potential high vulnerability to oil pollution.
The Falklands' population of king penguin (Aptenodytes patagonicus), is very small, but was still included in the census. The fourth main Falklands' penguin, the magellanic penguin (Spheniscus magellanicus), was not included in this census due to the difficulties of censusing a species that nests in burrows.
METHODS
Most breeding site locations were already known from fieldwork conducted prior to the 1995/96 census; however this information was checked by extensive consultation with landowners, to ensure that sites were not overlooked.
For a comprehensive census of such a large area, it was only possible to make a single visit to each site. Counts made during a single visit will inevitably underestimate the total number of breeding pairs, because of omitting pairs that have either not yet laid their eggs, or those that have already laid and subsequently failed. In general, counts were timed to correspond with the end of the egg-laying period, thereby ensuring that few pairs were still to lay, and allowing an assessment to be made of the underestimate due to pairs failing, by using failure rates during incubation from other studies.
The gentoo penguins concluded their first egg-laying by the end of October 1995. The 1995/96 census counted 15% of the gentoo population between 15 - 31 October, and the remainder between 1 November and 1 December. Because gentoos failing early tend to re-lay, and failure rates during incubation are low (c.1% per week), the magnitude of any underestimates resulting from differences in survey dates should be well below 5%.
Rockhopper penguins are much more synchronous, in terms of egg-laying, than gentoo penguins. Laying was concluded by mid-November 1995, and the 1995/96 census counted 98% of the rockhopper population between 1 November - 1 December (2% between 2-18 December). Repeated counts of rockhopper colonies in previous years showed that nest counts drop at a rate of about 3% per week for the first month after egg-laying, as a result of failed nests. It is therefore unlikely that the average underestimate of rockhopper populations exceeded 10%.
For most rockhopper and all gentoo breeding sites, the recorder made two separate counts of all occupied nests using a tally counter. The mean of the two counts was taken as the number of breeding pairs. Where these two counts differed by more than 10%, a third count was taken to give a mean value of three counts. In practice this was rarely necessary, and the spread of results was generally well below plus or minus 5%. Reference photographs were also taken at most sites for future comparison.
For the very large rockhopper colonies on Steeple Jason, Grand Jason, Bird and Beauchene Islands, direct ground counts were not possible. These sites were counted using a total of 60 randomly selected sample plots to determine the range of nesting densities, and the areas of the colonies was determined, to enable calculations of total breeding pairs to be made. A minimum of 10% and a maximum of 15% of the total colony area was sampled at each of the three sites. These measurements of area and density taken during the site visits were later compared against aerial photographs taken of the colonies. The margin of error for this methodology is greater than for direct counts, but should be within plus or minus 10%.
The breeding cycle of the king penguin is different from that of gentoos and rockhoppers, with chicks over-wintering at the colony, and a complete breeding cycle lasting over a year. This tends to result in individual birds having their following breeding cycle out of phase with its predecessor; thus large chicks and eggs may both occur in a colony at the same time. This complicates assessment of the breeding populations, and chick counts were taken instead. The estimation of error for chick counts is well below 5%, but will underestimate the number of breeding pairs by about 20% (Lewis Smith & Tallowin 1979).
RESULTS
KING PENGUIN
The 1995/96 census recorded a total of 339 chicks for the Falklands as a whole. Allowing for losses during incubation and chick-rearing, and the staggered breeding cycle, this figure gives an estimated Falklands population of around 400 breeding pairs. Volunteer Point, on the north-east coast of East Falkland, was the only king penguin breeding colony in the Falkland Islands, with individual pairs breeding in gentoos colonies at all other sites .
GENTOO PENGUIN
The 1995/96 population of gentoo penguins in the Falkland Islands was about 65,000 breeding pairs, with an estimated range of 61,750 - 68,250 pairs. There was a total of 81 breeding sites distributed throughout the archipelago, ranging in size from 7 to 5100 breeding pairs. Eighteen sites had breeding populations of >1000 pairs, between them totalling 58% of the overall population. The general distribution was: East Falkland - 16,000 pairs (24.5%), West Falkland - 24,000 pairs (37%) and Outer Islands - 25,000 pairs (38.5%).
ROCKHOPPER PENGUIN
The 1995/96 population estimate for rockhopper penguins in the Falkland Islands was 297,000 breeding pairs, with an estimated range of 267,000 - 327,000 pairs. There was a total of 36 breeding sites, ranging in size from 83 to 115,000 breeding pairs. These sites are distributed around most of the Falklands, but the greatest concentrations are on the outer islands. The general distribution was: East Falkland - 21,000 pairs (7%), West Falkland -11,000 pairs (4%) and Outer Islands - 265,000 pairs (89%).
DISCUSSION
KING PENGUIN
The present Falklands` population of around 400 breeding pairs is almost entirely concentrated at one location on the north-east of East Falkland. This colony has expanded from 38 chicks in 1980/81 (N. Keenleyside, unpublished data) to 330 chicks in 1995/96. Nevertheless this comprises less than 0.1% of a world population that has been increasing consistently since the 1970's (Woehler 1993), and the high rate of increase in the Falklands during this period is likely to be due in part to immigration from the large and expanding population on South Georgia. At least one bird banded on South Georgia has been resighted in the Falklands (O. Olsen, pers comm).
GENTOO PENGUIN
The Falkland Islands are one of twelve major breeding sites for this species (Robertson 1986). The 65,000 pairs in the Falklands are widely distributed throughout the archipelago, and represent about 20% of the world population; second in size only to South Georgia. Within the Falklands there are three sites (New Island, Steeple Jason and Saunders Island) that each hold more than 1% of the estimated world population of 318,000 pairs. However, comparison with Bennett's (1933) total of 116,000 pairs for the Falklands during 1932/33 suggests an overall decline of around 45%.
Comparison of single years, widely separated in time, can sometimes be unreliable, especially in a species whose population shows considerable interannual fluctuation (Croxall & Rothery, 1995). However, population counts from 21 colonies which have been monitored since 1988/89 show that the 1995/96 census did not coincide with a season of especially low population. Moreover, these data suggest that the decline has been continuing in recent years. Although no records exist as to the methodology employed during Bennett's (1933) census, his numerous publications testify to his reputation as a meticulous and experienced observer and naturalist, and gentoo penguins are a particularly easy species to count accurately. Even if the larger and hence more difficult sites such as the Jason Islands are excluded, comparable counts for the remaining sites still indicate a decline over the 60 year period.
ROCKHOPPER PENGUIN
The Falklands population, of around 300,000 pairs, represents the world's most important breeding site for this species. In addition, the Falkland Islands have 63% of the world population for this sub-species, with most of the remainder being on islands around the coast of Chile (Bingham and Mejias, In press). In the Falklands, the islands of Steeple Jason and Grand Jason to the north-west, and Beauchene to the south, hold the only very large concentrations (> 20,000 pairs) and these account for around 75% of the Falklands population.
Population counts from study sites monitored throughout the 1990's show that the 1995/96 census did not coincide with a year of naturally low populations. Thus the current population estimate is very considerably lower than the 3,169,000 pairs recorded by Bennett (1933) in 1932/33. Although Bennett gave no account of the methodology used, he states that his figures were most likely to be underestimates, and did not include the large colonies on Beauchene and Bird Island which currently hold 28% of the Falklands population. It therefore appears that the Falklands population has declined to about 10% of its 1932/33 level.
POPULATION CHANGES
Whereas populations of king penguins in the Falklands have increased in recent years, in line with world-wide trends, populations of gentoo and rockhopper penguins have decreased substantially over the last 60 years, perhaps by as much as 50% and 90% respectively. This is supported by data from more recent site studies which also suggest that the declines have continued into recent years. Kidney Island's rockhopper population declined from 3,000 pairs in 1960/61 to 240 pairs in 1994/95 (Bingham 1995), rockhopper colonies at New Island declined from >100,000 pairs in 1976/78 to 4,000 pairs in 1992 (Thompson 1993), and at Beauchêne Island the colony had declined from 300,000 pairs in 1980 (Lewis-Smith and Prince 1985) to 71,500 pairs in 1991 (Thompson 1993). The 1985/86 summer season was especially bad for rockhoppers, with tens of thousands of adults dying from starvation during their annual moult. Analysis of carcasses showed that they had died from starvation, and this was likely to have resulted from food shortages prior to the moult (Keymer, 1988).
It is not easy to account for these declines. Direct exploitation of penguins has diminished to insignificance. Killing birds to extract oil ceased at the beginning of the 20th century, and collecting of eggs for food has now declined to very low levels.
Commercial fisheries started around the Falklands in the 1960's, expanded greatly during the 1970's and 1980's, and in recent years has been generally stable since the Falkland Islands Government imposed a licensing regime in 1985. There is some evidence that penguin population size and breeding performance is related to food availability around the Falklands (Keymer, 1988; Thompson, 1989,1993; Bingham, 1995). There is no direct evidence that food availability to penguins has been affected by commercial fishing, but this possibility cannot be ruled out, especially in respect of squid fisheries, larval/juvenile squid being an important element of the diet of both rockhopper and gentoo penguins (Thompson 1994). It should also be noted that the breeding season diet of rockhoppers, appears to comprise of more Euphausids and less commercially fished species than that of the gentoo (Thompson 1993).
Loss or degradation of breeding habitat has probably occurred at some sites. due to erosion, fire or other anthropogenic activity. Disturbance from humans and stock may also have been (and remains) a problem in some areas, though there is little firm evidence that this or the current level of tourist visits have any discernible influence. Overall, none of these effects can explain large scale changes, especially at sites where breeding habitat loss and disturbance have been minimal or non-existent. There is also no evidence of increased impact from introduced predators, and many sites lack any introduced predatory species.
Rockhopper Penguins (of the subspecies E.c. filholi) have declined very substantially at the New Zealand Sub-Antarctic islands since the 1940's (Cunningham & Moors 1994, Cooper 1992). At these sites also there was no evidence that land-based influences were responsible. It was therefore suggested that changes in the marine environment may have occurred and affected the survival of penguins, either directly through physical factors or, more likely, indirectly through changes to the food web.
At a recent international workshop reviewing the status of penguins, it was clear that the large-scale declines in rockhopper penguin populations were of such magnitude as to justify treating the species as globally threatened (Vulnerable), according to the new IUCN criteria. A co-ordinated programme of research on this species at its most important population site, the Falkland Islands, is now long overdue.
ACKNOWLEDGEMENTS
My thanks go to the RAF Ornithological Society, and other dedicated volunteers who assisted with the surveys, the Commander, British Forces Falkland Islands, for arranging logistical support and aerial photographs, the Wellcome Trust for funding the project, and Dr. John Croxall for assisting with drafting the manuscript. Thanks to all the landowners who, virtually without exception, offered support in providing information, assistance and access to their land.
REFERENCES
Bennett, A.G. 1933. The penguin population of the Falkland Islands in 1932/33. Government Press, Falkland Islands. 4pp.
Bingham, M. 1995. Population status of penguin species in the Falkland Islands. Penguin Conservation, 8.1, 14-19.
Bingham, M. and Mejias, E. In Press. Penguin populations of the Magellanic Region. Scientia Marina.
Cooper, W. 1992. Rockhopper Penguins at the Auckland Islands. Notornis, 39, 66-67.
Croxall, J.P. 1992 Southern ocean environmental change: effects on seabird, seal and whale populations. Philosophical Transactions of the Royal Society of London, B, 338, 319-328.
Croxall, J.P. and Rothery, P. 1995. Population change in Gentoo Penguins Pygoscelis papua at South Georgia: potential roles of adult survival, recruitment and deferred breeding. In Penguin biology: Advances in research and management (eds P. Dann, I. Norman and P. Reilly) pp. 26-38. Surrey Beatty & Sons, Chipping Norton, Australia.
Croxall, J.P., McInnes, S.J. and Prince P.A. 1984 The status and conservation of seabirds at the Falkland Islands. In Status and conservation of the world's seabirds. ICBP Technical Publication No.2. 271-291.
Cunningham, D.M. and Moors, P.J. 1994. The decline of Rockhopper Penguins Eudyptes chrysocome at Campbell Island, Southern Ocean and the influence of rising sea temperatures. Emu, 94, 27-36.
Fraser, W.R., Trivelpiece, W.Z., Ainley, D.G. and Trivelpiece, S.G. 1992. Increases in Antarctic penguin populations: reduced competition with whales or a loss of sea ice due to environmental warming? Polar Biology, 11, 525-531.
Keymer, I.F. 1988. An investigation of Rockhopper Penguin mortality in the Falklands during the 1985/86 breeding season. Falkland Islands Foundation Project Report, Falkland Islands. 19pp.
Lewis Smith, R.I. and Tallowin, J.R.B. 1979. The distribution and size of King Penguin rookeries on South Georgia. British Antarctic Survey Bulletin, 49, 259-76.
Lewis Smith, R.I., & Prince, P.A. 1985. The natural history of Beauchene Island, Falkland Islands. Biological Journal of the Linnean Society, 24, 233-283.
Robertson, G. 1986. Population size and breeding success of the Gentoo Penguin at Macquarie Island. Australian Wildlife Research, 13, 583-587.
Thompson, K.R. 1989. An assessment of the potential for competition between seabirds and fisheries in the Falkland Islands. Falkland Islands Foundation Project Report, Falkland Islands. 94pp.
Thompson, K.R. 1993. Falkland Islands Seabird Monitoring Programme Summary of Results. Falklands Conservation Report SMP/3, Falkland Islands. 25pp.
Thompson, K.R. 1994. Predation on Gonatus antarcticus by Falkland Islands seabirds. Antarctic Science, 6, 269-274.
Woehler, E.J. 1993 The Distribution and Abundance of Antarctic and Subantarctic Penguins. Scientific Committee on Antarctic Research, University Printing Services, Cambridge. 76pp.
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Censo de los Pingüinos de las Islas Falklands
by Mike Bingham. (1996)
INTRODUCCION
Durante el verano de 1995/96, hubo un censo de todos los pingüinos de cria en Islas Falklands, para las especies Pingüino de Penacho Amarillo, Pingüino Papua y Pingüino Rey. El censo contó todas las poblaciones de cria para estas especies, y estudió el tamaño y situacion de cada colonia de cria. El Señor A.G.Bennett contó estos pingüinos en Islas Falklands durante 1932/33. Por esta razon, fue posible determinar los cambios durante los sesenta años pasados.
Hay cuatro principal especies de pingüinos que habitan en Islas Falklands:
PINGÜINO DE PENACHO AMARILLO (Eudyptes chrysocome chrysocome)
Estos pingüinos habitan en treinta y seis localidades en Islas Falklands, y en islas de Chile y Argentina. Viven en acantilados, en colonias de unos mil nidos. Abandonan las localidades de cria en invierno, y vuelven siempre en octubre a las mismas localidades. En Islas Falklands comen crustaceos (Euphausia lucens, Euphausia vallentini, Thysanoessa gregaria, Themisto sp.), calamar (Gonatus antarcticus, Loligo gahi, Teuthowenia sp.) y pescado (Croxall et al. 1985, Thompson 1993, 1994, Bingham 1995).
PINGÜINO PAPUA (Pygoscelis papua)
Estos pingüinos habitan en ochenta y uno localidades en Islas Falklands, y en las islas de Los Estados, Marion, Crozet, Kerguelen, Macquarie, Georgias del Sur, Heard y Prince Edward (Woelher 1993). Habitan en llanos costeros, en colonias de unos cien nidos. Quedan en estas localidades todo el año. En Islas Falklands comen pescado (Patagonotothen sp., Thysanopsetta naresi, Micromesistius australis), calamar (Loligo gahi, Gonatus antarcticus, Moroteuthis ingens) y crustaceos (Munida gregaria) (Thompson 1993, Bingham 1995).
PINGÜINO REY (Aptenodytes patagonicus)
Estos pingüinos tienen solamente una localidad de cria en Islas Falklands, y esta colonia es muy chica, pero son mucho mas grande en Islas Georgias del Sur. Permanecen en las localidades de cria todo el año. No existe informacion de su dieta para Islas Falklands al presente.
PINGÜINO DE MAGALLANES (Spheniscus magellanicus)
Estos pingüinos viven en cientos de kilometros de llanos costeros en Islas Falklands, Chile y Argentina. Porque viven en madrigueras, son demasiado dificil de contar en este censo. Abandonan las localidades de cria en invierno, y vuelven en septiembre. En Islas Falklands comen pescado (Micromesistius australis, Sprattus fuegensis, Patagonotothen sp.), calamar (Loligo gahi, Gonatus antarcticus, Moroteuthis ingens) y crustaceos (Munida gregaria) (Bingham 1995, Thompson 1993)
METODOLOGIA
El censo conto los pingüinos durante noviembre y diciembre 1995, despues de que los pingüinos pusieron sus huevos. Vehiculos de todo terreno, motocicletas, caballos, barcos, aviones y helicoptero fueron empleados para contar las colonias.
El censo conto todos los nidos de pingüinos para la mayor parte de las colonias, y estas sumas tienen exactitudes de mas o menos 5%. No fue posible contar todas las nidos de las colonias de Pingüinos de Penachos Amarillos en Steeple Jason, Grand Jason, Beauchene y Bird Islas. Para estas colonias solomente, el censo midio la densidad y area de los nidos, y calculó el numero de nidos. Estas cuatro sumas tienen exactitudes de mas o menos 10%.
Los Pingüinos Rey no tienen nidos, porque soportan su huevo o pollito en sus pies. Tambien no ponen huevos juntos, y la colonia tiene pollitos grande y huevos en el mismo tiempo. Por estas razones no es posible contar nidos, y para los Pingüinos Rey solomente el censo conto pollitos.
RESULTADOS
PINGÜINO DE PENACHO AMARILLO
Habian 300,000 nidos de Pingüino de Penacho Amarillo en Islas Falklands en el verano de 1995/96. Este poblacion es mucho mas pequeña que en 1932/33, cuando Snr. Bennett conto 3,169,000 nidos (Bennett 1933). Ahora el poblacion de Pingüino de Penacho Amarillo en Islas Falklands es solomente 10% de la poblacion de hace sesenta años.
El numeros de pingüinos durante el censo de 1995 (Bennett 1932/33 en parentesis) estan:
Continente Este 21,000 nidos (154,000 nidos)
Continente Oeste 11,000 nidos (24,000 nidos)
Otros Islas 265,000 nidos (2,991,000 nidos)
TOTAL DE ISLAS FALKLANDS 297,000 nidos (3,169,000 nidos)
PINGÜINO PAPUA
Habian 65,000 nidos de Pingüino Papua en Islas Falklands en el verano de 1995/96. Este poblacion es mas pequeño que en 1932/33, cuando Snr. Bennett conto 116,000 nidos (Bennett 1933).
El numeros de pingüinos durante el censo de 1995 (Bennett 1932/33 en parentesis) estan:
Continente Este 16,000 nidos (18,000 nidos)
Continente Oeste 24,000 nidos (16,000 nidos)
Otros Islas 25,000 nidos (82,000 nidos)
TOTAL DE ISLAS FALKLANDS 65,000 nidos 116,000 nidos
PINGÜINO REY
Habian 339 pollitos de Pingüino Rey en Islas Falklands en 1995/96. Snr. Bennett no conto estos pingüinos, pero Snr. Keenleyside conto 38 pollitos en la colonia en 1980/81. La poblacion de Islas Falklands es mas grande ahora que hace quince años, pero todavia es muy pequeño.
DISCUSION
Todavia Islas Falklands tienen lamitad y mucho mas de la poblacion mundial de esta subespecie de Pingüino de Penacho Amarillo. La mayor parte de otros Pingüinos de Penachos Amarillos estan en islas de Chile, especialmente las islas de Noir, Diego Ramirez, Barnaveldt, Ildefonso y Recalada (Venegas 1984, 1991, Soto 1990). Los otros Pingüinos de Penachos Amarillos estan en Argentina en Islas de Los Estados y Puerto Deseado (Frere et al. 1993). Es importante saber cuantos nidos hay en estas islas, y si estas colonias van disminuyendo tambien.
Ahora Islas Falklands tienen un cuarto de la poblacion mundial de Pingüino Papua. Solomente la poblacion de Islas Falklands va disminuyendo, y es importante saber por qué.
Islas Falklands tienen menos que 0.1% de la poblacion mundial de Pingüino Rey, y otras colonias aumentan tambien.
Es importante contar la poblacion de Pingüinos de Magallanes en Islas Falklands. Es probable que la poblacion de Islas Falklands haya entre cien mil doscientos mil nidos. Islas Falklands tienen una importante proporcion de la poblacion mundial de Pingüinos de Magallanes. Sera necesario facilitar la metodologia mas indicada para este especie. Los otros Pingüinos de Magallanes estan en Chile y Argentina, y es posible que estos pais pueden ayudar con este.
REFERENCIAS
Bennett A.G. (1933) The Penguin Population of the Falkland Islands in 1932/33. Imprenta de gobierno, Islas Falklands.
Bingham M. (1995) Population Status of Penguin Species in the Falkland Islands. Periodico "Penguin Conservation" Tomo 8, Numero 1, 14-19.
Croxall J.P., Prince P.A., Baird A. y Ward P. (1985) The diet of the Southern Rockhopper Penguin at Beauchene Island. Zoological Society of London206, 485-96
Frere E., Gandini M., Gandini P., Holik T., Lichtschein V. y Day M.O. (1993) Variacion anual en el numero de adultos reproductivos en una nueva colonia de pingüino de penacho amarillo en Isla Pingüino. Hornero 13: 293.
Soto N. (1990) Proyecto de proteccion y manejo de las colonias de pingüinos presentes en isla Rupert e isla Recalada Reserva Nacional Alacalufes. CONAF, República de Chile Ministerio de Agricultura, Punta Arenas, Chile.
Thompson K.R. (1993) Falkland Islands Seabird Monitoring Programme Summary of Results. Reportaje de Falklands Conservation SMP/3
Thompson K.R. (1994) Predation on Gonatus antarcticus by Falkland Islands seabirds. Antarctic Science 6. 269-274.
Venegas C. (1984) Estado de las poblaciones de pingüino de penacho amarillo y macaroni en la isla Noir. Informe Instituto de la Patagonia, Punta Arenas, Chile. #33
Venegas C. (1991) Estudio de cuantificacion poblacional de pingüinos crestados en isla Recalada. Informe Instituto de la Patagonia, Punta Arenas, Chile. #55.
Woehler E.J. (1993) The Distribution and Abundance of Antarctic and Subantarctic Penguins. Scientific Committee on Antarctic Research, Cambridge, UK.
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Penguins of South America and the Falkland Islands
by Mike Bingham. Published 1998 in PENGUIN CONSERVATION 11(1): 8-15. .
INTRODUCTION TO THE REGION
World-wide there are 17 species of penguin, of which 7 regularly breed around South America and the Falkland Islands. Three of these species are of the Genus Spheniscus, and are found nowhere else in the world. These are the Magellanic Penguin (Spheniscus magellanicus) common around southern South America and the Falkland Islands, the Humboldt Penguin (Spheniscus humboldti) restricted to the Pacific coast of Chile and Peru, and the Galapagos Penguin (Spheniscus mendiculus) found only at the Galapagos Islands off the coast of Equador.
The King Penguin (Aptenodytes patagonicus) has a limited presence in the region, with a breeding population of around 400 pairs in the Falkland Islands (Bingham 1996). King Penguins have not bred in South America since the colony on Islas de los Estados was wiped out by sealers during the last century. The Falkland Islands hold around 20% of the world population of Gentoo Penguin (Pygoscelis papua), with a total population of 65,000 breeding pairs at 81 sites (Bingham 1996).
The Falkland Islands and South America are home to two species of the Genus Eudyptes; the Southern Rockhopper (Eudyptes chrysocome chrysocome) and the Macaroni (Eudyptes chrysolophus). The Southern Rockhopper is a subspecies that is restricted to the Falkland Islands and South America, with the Falkland Islands holding a breeding population of about 300,000 pairs at 36 sites (Bingham 1996). The Falkland Islands population of Macaroni Penguins is very small, with no individual colonies and only individual pairs found breeding amongst Rockhoppers colonies. The total Falklands population stands at no more than about 50 pairs.
THE CENSUS
By comparison to other areas of research, conducting counts of breeding populations can seem fairly mundane. Nevertheless the value of data obtained from population censuses should never be underestimated. It is only by recording population size and distribution that we are able to determine with any accuracy whether a population is thriving or declining, or how a population has been affected by disasters such as an oil spill or El Niño.
During 1995/96, a population census of all penguin species (except the Magellanic Penguin) was conducted around the Falkland Islands (Bingham 1996). Every breeding colony was visited, and population totals for each species obtained. Comparing this data with previous studies revealed that the Southern Rockhopper population had crashed to a fraction of its former size (Bennett 1933, Bingham 1994c Bingham 1995a, Bingham 1996). With no obvious reason for this dramatic decline, apart from speculation about commercial fishing, it became a priority to census the remainder of the world population located in South America, to determine how wide-spread the decline had been.
It had been shown during the 1995/96 census of the Falkland Islands, that it requires little extra effort to census all penguin species during the course of such a census. The only exception to this was the Magellanic Penguin, which because of its widespread, low-density distribution in burrows, made it impossible to census with methods employed for surface nesting species. For this reason the Magellanic Penguin had been excluded from the Falkland Islands census.
On that basis it was decided that a census would be conducted of all South American penguins during the 1996/97 breeding season, except for those of the Genus Spheniscus. In theory this meant that all species covered by the Falkland Islands census would be included, although King and Gentoo Penguins were not expected to be encountered during the South American census.
During the 1995/96 Falkland Islands census it had been possible to conduct ground counts of incubating pairs at each of the breeding colonies, because most colonies were relatively accessible (Bingham 1996). By contrast, many of the South American colonies are remote and inaccessible, and any attempt to conduct ground counts of each and every colony would have been doomed to failure. It was therefore decided from the outset that the census would be conducted by light aircraft, thereby negating the need to get ashore at difficult and remote sites.
The location of all the Falkland Islands breeding sites had been known prior to the commencement of the 1995/96 census (Bingham 1996), but this was certainly not the case for South America. Although data did exist for a number of known breeding sites around South America, it was likely that other sites existed that had not been recorded. This was another reason for favouring an aerial census, since it provided the opportunity to cover large areas of suitable coastline in search of previously unrecorded colonies. This certainly reduced the margin of error that would otherwise have resulted from new sites being overlooked, however the margin of error for the actual counts was clearly greater for aerial counts than for ground counts.
In order to quantify the margin of error likely to be expected from aerial counts, a number of aerial censuses were made of Rockhopper colonies in the Falkland Islands for which the number of breeding pairs was also determined by ground counts. These aerial counts differed by a maximum of 14% from ground counts made of the same colony, giving a total margin of error of +/- 20% for aerial census data (Bingham 1996).
The 1996/97 aerial census was conducted throughout the known Eudyptes breeding ranges of Chile and Tierra del Fuego. The Atlantic coast of mainland Argentina was excluded from the census, since this coastline has been well studied, and does not hold any breeding sites for species covered by the census, other than a very small Rockhopper colony on Isla Pingüino, near Puerto Deseado. This colony is regularly monitored as part of an ongoing research programme, and population data from their research was used in favour of duplicating results (Frere et al. 1993).
CENSUS RESULTS
KING PENGUIN
As expected, no King Penguins were recorded anywhere in South America.
GENTOO PENGUIN
Somewhat surprisingly, a very small Gentoo breeding colony was discovered on Islas de los Estados, containing almost 100 breeding pairs. This was the only breeding colony of Gentoo Penguin recorded in South America.
SOUTHERN ROCKHOPPER
The 1996/97 census showed that South America holds a breeding population of about 175,000 pairs of Southern Rockhoppers, at a total of 15 breeding sites. Apart from the very small colony near Puerto Deseado (Frere et al. 1993), these breeding sites are restricted to the islands off Tierra del Fuego and Chile. Combined with the Falkland Islands population of 300,000 pairs at 36 sites (Bingham 1996), this gives a world population of 475,000 breeding pairs at 51 sites for the subspecies Eudyptes c.chrysocome. (South Georgia has been known to hold a few breeding pairs, but no more than 10 pairs have been recorded).
MACARONI PENGUIN
The 1996/97 census showed that South America holds a breeding population of about 12,000 pairs of Macaroni, at a total of 9 sites. These sites are all restricted to the islands off Tierra del Fuego and Chile. Only the islands of Diego Ramirez, Ildefonso and Noir hold more than a thousand breeding pairs.
DISCUSSION
No breeding King Penguins were observed in South America during the 1996/97 census. The Falkland Islands population stood at around 400 breeding pairs during the 1995/96 census (Bingham 1996), and has rapidly expanded from a population of less than 100 pairs recorded during 1980/81 (Bingham 1995a). With a world population of around 1,500,000 pairs (Croxall, In press), the Falkland Islands population is of regional rather than global importance.
A colony of a little under 100 breeding pairs of Gentoo Penguin was discovered on Islas de los Estados during the 1996/97 census. The Falkland Islands population stood at 65,000 breeding pairs during the 1995/96 census (Bingham 1996) out of an estimated world population of 320,000 pairs (Croxall, In press). The 1995/96 Falkland Islands census indicated a population decline of around 45% since a similar census conducted during 1932/33 (Bennett 1933).
Annual counts of selected breeding sites around the Falkland Islands suggested that much of this decline had occurred during the late 1980s and early 1990s, with low breeding success also being observed during that period (Bingham 1994a, Bingham 1994d, Bingham 1995a). Continued monitoring of these sites since then indicates that the Falkland Islands population has now risen to around 81,000 breeding pairs, with high breeding success rates having been recorded since 1993/94. Gentoo populations are known to fluctuate greatly, and it is plausible that the decline observed previously was merely part of a natural cycle.
The world population of Southern Rockhopper Penguins now stands at around 475,000 breeding pairs, with 63% of the population in the Falkland Islands and 37% in South America.
Comparison with previous census data (Bennett 1933) indicates that the Falkland Islands population has crashed to just 10% of its former size, with much of this decline having occurred during the 1980s and early 1990s (Bingham 1994c, Bingham 1995a, Bingham 1996). Evidence of this dramatic decline can also be seen from the breeding sites themselves. The Falkland Islands breeding sites feature old colonies which have destroyed the vegetation by years of occupancy, leaving only lichen covered rocks and stones around the nest-site. The huge breeding colonies that once produced these areas of barren ground, have now been reduced to small clusters of birds huddled in the centre of their stony territories.
The South American population shows no such evidence of decline, with breeding sites featuring a healthy mixture of new, middle-aged and old colonies, indicating a natural cycle of fluctuation and regeneration. Comparison with previous census data (Venegas 1984, Venegas 1991, Woehler 1993) also indicates that the South American population had been stable throughout the 1980s and 1990s, covering the period when over half the Falkland Islands population had died from starvation. The reason for such differing fortunes is unknown, although it is interesting to note that the waters around Tierra del Fuego and Chile are not heavily fished, whilst those around the Falkland Islands are. In the Falkland Islands, even internationally recognised sites, such as Beauchêne Island which is being considered for World Heritage status, have fleets of fishing boats operating just 3 miles from breeding Rockhoppers.
The Macaroni populations of South America (12,000 pairs) and the Falkland Islands (~50 pairs) must be looked at in the light of a world population of around 9 million breeding pairs (Croxall, In press). These populations are therefore of regional rather than international importance. There were no obvious signs of decline amongst the South American population, and no evidence to suggest that the population has changed greatly over recent years. The Macaroni is the most numerous of all the world's penguins.
Although the Magellanic Penguins were not included in the 1995/96 and 1996/97 censuses, that is not to say that no work has been done on this species. The current population along the coast of mainland Argentina is estimated to be 650,000 breeding pairs (Gandini et al. In press). Observations of distribution around Tierra del Fuego and Chile during the 1996/97 census suggest that these regions hold a population at least as large as that of mainland Argentina, giving a South American population of at least 1,300,000 pairs. Studies by the Environmental Research Unit indicate that the Falkland Islands population must be well in excess of 100,000 pairs, giving a minimum world population of around one and a half million breeding pairs.
Annual monitoring of selected colonies (Bingham 1994b, Bingham 1995a, Bingham 1995b) shows that the Magellanic Penguin population of the Falkland Islands has declined to about half its 1980s level. These declines coincided with observations of low breeding success up until 1993/94.
In addition to its Penguin Monitoring Programme in the Falkland Islands, the Environmental Research Unit now conducts similar studies at a number of Chilean breeding sites along the Straits of Magellan. These studies suggest that the Magellanic Penguin decline observed in the Falkland Islands has not been evident in the Magellanic region of Chile, despite its close proximity and similar breeding habitat to the Falkland Islands.
One such site is Isla Magdalena, which lies in the Straits of Magellan and covers an area of less than 1 sq.km. The 1997/98 census conducted by the Environmental Research Unit shows that this tiny island holds a population of around 41,000 breeding pairs of Magellanic Penguin; equivalent to about a third of the entire Falkland Islands population. Comparison with a similar census conducted during 1940 suggests little significant change over the last 60 years (CONAF).
The 1997/98 population in the Straits of Magellan increased by an average of 17% since 1996/97. Chick survival rates were also high during 1997/98, with the lowest rate observed in the Straits of Magellan (range 1.28 - 1.71 chicks fledged per nest) still being higher than the highest rate observed in the Falkland Islands (range 0.79 - 1.23 chicks fledged per nest).
Further evidence of the differing fortunes of the two regions can be seen from the breeding sites themselves. Magellanic Penguin colonies around the Falkland Islands generally feature a very high percentage of unoccupied burrows, with an average of more than 70% of burrows being unoccupied. Similar breeding sites in the Straits of Magellan hold less than half the proportion of unoccupied burrows (< 35%), suggesting lower levels of adult mortality or higher levels of recruitment. There is no commercial fishing activity around the Straits of Magellan.
South America is also home to the Humboldt Penguin and the Galapagos Penguin, but these species were outside the scope of this census. The Environmental Research Unit has not conducted any research on either of these species, but there are other organisations that have. The estimated world population sizes of these species are less than 15,000 and 1,000 breeding pairs respectively. (Vargas 1996, Zavalaga 1997).
ACKNOWLEDGEMENTS
Thanks go to CONAF, Instituto de la Patagonica, Fundación Otway, Aerovias DAP, Ricardo Fuentes and Elena Mejias.
REFERENCES
Bennett, A.G. (1933) The penguin population of the Falkland Islands in 1932/33. Government Press, Falkland Islands. 4pp.
Bingham, M. - (1994a) Conservation Report on Gentoo Penguins. Penguin News, Vol.6, No.4: 9.
Bingham, M. - (1994b) Conservation Report on Magellanic Penguins. Penguin News, Vol.6, No.20: 10.
Bingham, M. - (1994c) Conservation Report on Rockhopper Penguins. Penguin News, Vol.6, No.21: 9.
Bingham, M. - (1994d) Gentoo Penguin population trends: 1987/88 - 1993/94, The Warrah, 5: 4-5.
Bingham, M. - (1995a) Population status of penguin species in the Falkland Islands. Penguin Conservation, 8(1): 14-19.
Bingham, M. - (1995b). Seabird Surveys: 1994-95 Report. The Warrah, 5: 5.
Bingham, M. - (1996) Penguin Population Census 1995-96. The Warrah, 10: 6-7.
Croxall, J.P. (ed.) - In Press. Penguin Conservation Assessment: Antarctic and Subantarctic Species. In: Ellis, S. (ed.) Penguin Conservation Assessment. IUCN Conservation Breeding Specialist Group.
Frere, E., Gandini, M., Gandini, P., Holik, T., Lichtschein V. and Day M.O. - (1993) Variación anual en el número de adultos reproductivos en una nueva colonia de pingüino penacho amarillo en Isla Pingüino (Santa Cruz, Argentina). Hornero, 13: 293-294.
Gandini, P., E. Frere and P.D. Boersma - In Press. Status and conservation of Magellanic Penguins in Patagonia, Argentina. Bird Conservation International.
Vargas, H. - (1996) Galapagos Penguin Census of 1995. Penguin Conservation, 9(1): 2-4.
Venegas, C. - (1984) Estado de las poblaciones de Pingüino de Penacho Amarillo y Macaroni en la Isla Noir, Chile. Informe Instituto de la Patagonia, 33.
Venegas, C. - (1991) Estudio de cuantificacion poblacional de pingüinos crestados en Isla Recalada. Informe Instituto de la Patagonia, 55.
Woehler, E.J. - (1993) The distribution and abundance of Antarctic and Subantarctic Penguins. SCAR, Cambridge.
Zavalaga, C.B. and Paredes, R. - (1997) Humboldt Penguins at Punta San Juan, Peru. Penguin Conservation, 10(1): 6-8.
