21 research outputs found
Population Trends of a Mixed-Species Colony of Humboldt and Magellanic Penguins in Southern Chile after Establishing a Protected Area
Worldwide marine protected areas (MPAs) have been designated to protect marine resources, including top predators such as seabirds. There is no conclusive information on whether protected areas can improve population trends of seabirds when these are further exploited as tourist attractions, an activity that has increased in past decades. Humboldt Penguins (Spheniscus humboldti) and Magellanic Penguins (S. magellanicus) breed sympatrically on Puñihuil Islets, two small coastal islands off the west coast of Chiloé Island (41° S) in southern Chile that are subject to exploitation for tourism. Our goal was to compare the population size of the mixed colony of Humboldt and Magellanic Penguins before and after protection from unregulated tourism and freely roaming goats in 1997. For this purpose, two censuses were conducted in 2004 and 2008, and the numbers compared with those obtained in 1997 by other authors. The proportion of occupied, unoccupied, and collapsed/flooded burrows changed between years; there were 68% and 34% fewer collapsed burrows in 2004 and 2008, respectively, than in 1997. For the total number of burrows of both species, we counted 48% and 63% more burrows in 2004 and 2008, respectively, than in 1997. We counted 13% more burrows of Humboldt Penguins in 2008 than in 1997, and for Magellanic Penguins, we estimated a 64% increase in burrows in 2008. Presumably, this was as a result of habitat improvement attributable to the exclusion of tourists and the removal of goats from the islets. Although tourist visits to the islets are prohibited, tourism activities around the colonies are prevalent and need to be taken into account to promote appropriate management
Tendance d’une colonie mixte de Manchots de Humboldt et de Manchots de Magellan dans le sud du Chili à la suite de l’établissement d’une aire protégée
Worldwide marine protected areas (MPAs) have been designated to protect marine resources, including top predators such as seabirds. There is no conclusive information on whether protected areas can improve population trends of seabirds when these are further exploited as tourist attractions, an activity that has increased in past decades. Humboldt Penguins (Spheniscus humboldti) and Magellanic Penguins (S. magellanicus) breed sympatrically on Puñihuil Islets, two small coastal islands off the west coast of Chiloé Island (41° S) in southern Chile that are subject to exploitation for tourism. Our goal was to compare the population size of the mixed colony of Humboldt and Magellanic Penguins before and after protection from unregulated tourism and freely roaming goats in 1997. For this purpose, two censuses were conducted in 2004 and 2008, and the numbers compared with those obtained in 1997 by other authors. The proportion of occupied, unoccupied, and collapsed/ flooded burrows changed between years; there were 68% and 34% fewer collapsed burrows in 2004 and 2008, respectively, than in 1997. For the total number of burrows of both species, we counted 48% and 63% more burrows in 2004 and 2008, respectively, than in 1997. We counted 13% more burrows of Humboldt Penguins in 2008 than in 1997, and for Magellanic Penguins, we estimated a 64% increase in burrows in 2008. Presumably, this was as a result of habitat improvement attributable to the exclusion of tourists and the removal of goats from the islets. Although tourist visits to the islets are prohibited, tourism activities around the colonies are prevalent and need to be taken into account to promote appropriate management.Les aires marines protégées ont été établies à l’échelle mondiale pour protéger les ressources marines, dont les prédateurs au sommet de la chaîne alimentaire comme les oiseaux marins. Rien n’indique de façon concluante que la protection
d’aires permet une hausse des populations d’oiseaux marins dans les cas oĂą ces populations reprĂ©sentent toujours une attraction touristique, activitĂ© dont la popularitĂ© a augmentĂ© au cours des dernières dĂ©cennies. Les Manchots de Humboldt (Spheniscus humboldti) et les Manchots de Magellan (S. magellanicus) nichent de façon sympatrique sur les Ă®lots Puñihuil, deux petites Ă®les au large de la cĂ´te ouest de l’île de ChiloĂ© (41° S.) qui font l’objet de visites touristiques dans le sud du Chili. L’objectif de notre Ă©tude Ă©tait de comparer la taille des deux populations de manchots avant et après l’établissement d’une rĂ©glementation touchant le tourisme et les chèvres en libertĂ© en 1997. Ă€ cette fin, deux relevĂ©s ont Ă©tĂ© effectuĂ©s en 2004 et 2008, et les rĂ©sultats ont Ă©tĂ© comparĂ©s Ă ceux obtenus en 1997 par d’autres auteurs. La proportion de terriers occupĂ©s, non occupĂ©s ou effondrĂ©s/inondĂ©s a variĂ© selon les annĂ©es; ainsi, il y a eu 68 % et 34 % moins de terriers effondrĂ©s en 2004 et 2008, respectivement, qu’en 1997. Pour ce qui est du nombre de terriers des deux espèces, nous avons comptĂ© 48 % et 63 % plus de terriers en 2004 et 2008, respectivement, qu’en 1997. Nous avons comptĂ© 13 % plus de terriers de Manchots de Humboldt en 2008 par rapport Ă 1997, et avons observĂ© une hausse de 64 % pour les terriers de Manchots de Magellan en 2008. Nous pouvons prĂ©sumer que ces hausses rĂ©sultent de l’amĂ©lioration de l’habitat consĂ©cutive Ă l’exclusion des touristes et au retrait des chèvres des Ă®lots. MĂŞme si les visites touristiques sont maintenant interdites sur les Ă®lots, l’activitĂ© touristique aux abords des colonies a toujours cours et doit ĂŞtre prise en compte si on veut mettre en place une gestion adĂ©quate.Fil: Reyes Arriagada, Ronnie. Universidad Austral de Chile; Chile;Fil: Hiriart Bertrand, Luciano. Universidad Andres Bello; Chile;Fil: Riquelme, Victoria. Universidad Austral de Chile; Chile;Fil: Simeone, Alejandro. Universidad Andres Bello; Chile;Fil: PĂĽtz, Klemens. Antartic Research Trust; Suiza;Fil: LĂĽthi, Benno. Antartic Research Trust; Suiza;Fil: Raya Rey, Andrea NĂ©lida. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones Cientificas; Argentina
Diving patterns of breeding female rockhopper penguins (Eudyptes chrysocome): Noir Island, Chile
The diving behaviour of female southern rockhopper penguins (Eudyptes chrysocome) was studied at Noir Island (54°30′S-73°00′W), Chile, in the southeast Pacific Ocean. This isolated island is located at the edge of the continental shelf in an area where the Humboldt Current originates, and holds a population of more than 150,000 breeding pairs. On 13 December 2005, four TDRs were successfully attached to females at the end of the brooding period and recorded diving activity at intervals of 2 s over the next 4 weeks. In total, 40 complete foraging trips were recorded. Trip duration was on average 42.4 ± 40.1 h and the proportion of overnight trips (60%) was the highest value found so far for this species. Mean dive depth and dive duration was 20.6 ± 19.4 m and 63.7 ± 36.4 s, respectively. The diving effort was higher than that of brooding females from the Indian Ocean and comparable with that of conspecifics from colonies in the southwest Atlantic in terms of diving rate (38 ± 14.2 dives h-1), but slightly lower as regards the proportion of time spent underwater (61 ± 10.5%). This study confirms that the diving behaviour of rockhopper penguins varies as a function of the physical and biological characteristics of the foraging areas and of the particular stage of the breeding season.Fil: Raya Rey, Andrea NĂ©lida. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: PĂĽtz, Klemens. Antarctic Research Trust; Reino UnidoFil: Luna Jorquera,Guillermo. Universidad CatĂłlica del Norte; ChileFil: LĂĽthi, Benno. Antarctic Research Trust; SuizaFil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; Argentina. Wildlife Conservation Society; Estados Unido
Post-moult movements of sympatrically breeding Humboldt and Magellanic Penguins in south-central Chile
Ten Humboldt (Spheniscus humboldti) and eight Magellanic Penguins (S. magellanicus) were successfully equipped with satellite transmitters in March 2009 on Islotes Puñihuil in central south-Chile to follow their post-moult dispersal. Overall, Humboldt Penguins could be followed for a mean period of 49 ±18 days (range: 25–93) and Magellanic Penguins for 57 ±12 days (range 35–68). Irrespective of species and sex, seven study birds remained in the vicinity of their breeding ground throughout the transmission period. All other penguins moved northwards, either only a relatively short distance (max 400 km) to Isla Mocha at 38°S (n=3) or further north beyond 35°S (n=8). However, eight of these birds (73%) turned south again towards the end of the individual tracking periods. The total area used by both species during the tracking period was restricted to a coastal area stretching from the breeding site at 42°S about 1000 km to the north at about 32°S. The area used by Humboldt penguins overlapped by 95% the area used by Magellanic penguins, whereas the area used by the latter species was much larger and overlapped only by 45% with the area used by Humboldt penguins. Overall, our results indicate that Magellanic Penguins in the Pacific Ocean are probably less migratory than their conspecifics on the Atlantic side, while Humboldt Penguins appear to be more migratory than previously anticipated. In general, there was a poor relationship between preferred foraging areas and chlorophyll-a, as a proxy for primary productivity, indicating the limitations of using remote-sensed primary productivity as a proxy to interpret the foraging behaviour of marine predators. In addition, there was also no clear relationship between the preferred foraging areas and the amount of regional fish catches by artisanal fishery
Comparative foraging behaviour of sympatric Humboldt and Magellanic Penguins reveals species-specific and sex-specific strategies
How closely related marine organisms mitigate competition for resources while foraging at sea is not well understood, particularly the relative importance of interspecific and intraspecific mitigation strategies. Using location and time–depth data, we investigated species-specific and sex-specific foraging areas and diving behaviour of the closely related Humboldt (Spheniscus humboldti) and Magellanic (S. magellanicus) Penguins breeding in sympatry at Islotes Puñihuil in southern Chile during the chick-rearing period. The average duration of foraging trips was <20 h and did not differ significantly between species or between sexes of each species. Magellanic Penguins made significantly deeper and longer dives than Humboldt Penguins. Males of both species made significantly longer dives than females. Total distance travelled per foraging trip was significantly greater for males than for females, and females made more direct trips (less sinuous) than males. Foraging effort was concentrated in waters up to 15 km to the west and south-west of the colony. The overlap in density contours was lower between species than between sexes within a species. In general, dive characteristics and foraging areas differed more between Magellanic and Humboldt Penguins than between the sexes of each species. In contrast to the findings of studies of flying seabirds, the foraging behaviour of these penguins differs more between species than between sexes.Fil: Raya Rey, Andrea NĂ©lida. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro Austral de Investigaciones CientĂficas; ArgentinaFil: PĂĽtz, Klemens. Antarctic Research Trust; AlemaniaFil: Simeone, Alejandro. Universidad AndrĂ©s Bello; ArgentinaFil: Hiriart Bertrand, Luciano. Universidad AndrĂ©s Bello; Chile. University of California at San Diego; Estados UnidosFil: Reyes Arriagada, Ronnie. Universidad Austral de Chile; Chile. Universidad de Magallanes; ChileFil: Riquelme, Victoria. Universidad de Magallanes; Chile. Universidad Austral de Chile; ChileFil: LĂĽthi, Benno. Antarctic Research Trust; Suiz
Marathon penguins - Reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period.
Migratory species often roam vast distances bringing them into contact with diverse conditions and threats that could play significant roles in their population dynamics. This is especially true if long-range travels occur within crucial stages of a species' annual life-cycle. Crested penguins, for example, usually disperse over several hundreds of kilometres after completing the energetically demanding breeding season and in preparation for the costly annual moult. A basic understanding of crested penguins' pre-moult dispersal is therefore paramount in order to be able to assess factors affecting individual survival. The Fiordland penguin, or Tawaki, the only crested penguin species breeding on the New Zealand mainland, is currently one of the least studied and rarest penguin species in the world. We successfully satellite tracked the pre-moult dispersal of 17 adult Tawaki from a single colony located in the species' northern breeding distribution. Over the course of 8-10 weeks the penguins travelled up to 2,500 km away from their breeding colony, covering total swimming distances of up to 6,800 km. During outbound travels all penguins headed south-west within a well-defined corridor before branching out towards two general trip destinations. Birds leaving in late November travelled towards the Subtropical Front some 800 km south of Tasmania, whereas penguins that left in December headed further towards the subantarctic front. Using K-select analysis we examined the influence of oceanographic factors on the penguins' dispersal. Water depth, surface current velocity and sea level anomalies had the greatest influence on penguin movements at the subantarctic Front, while sea surface temperature and chlorophyll a concentration were key for birds travelling to the subtropical front. We discuss our findings in the light of anthropogenic activities (or lack thereof) in the regions visited by the penguins as well as the potential consequences of Tawaki pre-moult dispersal for the species' breeding distribution on the New Zealand mainland