Katrin Ludynia

Evaluating the Impact of Handling and Logger Attachment on Foraging Parameters and Physiology in Southern Rockhopper Penguins

Logger technology has revolutionised our knowledge of the behaviour and physiology of free-living animals but handling and logger attachments may have negative effects on the behaviour of the animals and their welfare. We studied southern rockhopper penguin (Eudyptes chrysocome) females during the guard stage in three consecutive breeding seasons (2008/09−2010/11) to evaluate the effects of handling and logger attachment on foraging trip duration, dive behaviour and physiological parameters. Smaller dive loggers (TDRs) were used in 2010/11 for comparison to larger GPS data loggers used in all three seasons and we included two categories of control birds: handled controls and PIT control birds that were previously marked with passive integrative transponders (PITs), but which had not been handled during this study. Increased foraging trip duration was only observed in GPS birds during 2010/11, the breeding season in which we also found GPS birds foraging further away from the colony and travelling longer distances. Compared to previous breeding seasons, 2010/11 may have been a period with less favourable environmental conditions, which would enhance the impact of logger attachments. A comparison between GPS and TDR birds showed a significant difference in dive depth frequencies with birds carrying larger GPS data loggers diving shallower. Mean and maximum dive depths were similar between GPS and TDR birds. We measured little impact of logger attachments on physiological parameters (corticosterone, protein, triglyceride levels and leucocyte counts). Overall, handling and short-term logger attachments (1–3 days) showed limited impact on the behaviour and physiology of the birds but care must be taken with the size of data loggers on diving seabirds. Increased drag may alter their diving behaviour substantially, thus constraining them in their ability to catch prey. Results obtained in this study indicate that data recorded may also not represent their normal dive behaviour.

Surviving off junk: low-energy prey dominates the diet of African penguins Spheniscus demersus at Mercury Island, Namibia, between 1996 and 2009

The diet of African penguins Spheniscus demersus in Namibia consisted mainly of sardine Sardinops sagax in the 1950s. Since the collapse of pelagic fish stocks in the 1970s, birds fed mainly on bearded (pelagic) goby Sufflogobius bibarbatus, a low-energy prey species. We present diet data for African penguins breeding at Mercury Island, the largest colony for this species in Namibia, between 1996 and 2009. Bearded goby was the main prey item throughout the study period, both in terms of frequency of occurrence (67.8%; SD 31.2) and in terms of mass (59.2%; SD 31.5). Diet composition varied throughout the year as well as between years; birds occasionally fed on a variety of fish species other than bearded goby. In Namibia, poor prey abundance is considered as a major factor contributing to the decline of penguin numbers after the collapse of the sardine stocks. However, bearded goby appears to be relatively abundant along Namibias southern coast and low prey quality rather than low abundance appears to be a key factor influencing population dynamics of African penguins and other marine top predators in southern Namibia.

Seasonal and Regional Variation in the Diet of the Kelp Gull in Northern Chile

Abstract The feeding ecology of the Kelp Gull (Larus dominicanus) was studied during the 2002-03 breeding season at Coquimbo, northern Chile. Food composition was studied by analyzing pellets regurgitated by Kelp Gulls living in different habitats. Birds breeding or resting near fishing ports used these as their main feeding grounds. Birds breeding on offshore islands fed mainly on intertidal organisms and olives. A comparison between the food of breeders and non-breeding birds during the breeding season showed a difference in diet composition of breeders, who fed more on fish of high energy density while non-breeding birds continued feeding on a wide range of organisms and waste. Observations in a fishing harbor and at sea demonstrated that fisheries waste was an important food source for the birds. The inshore distribution at sea was related to the location of fishing ports and breeding colonies.

Hemosporidian blood parasites in seabirds—a comparative genetic study of species from Antarctic to tropical habitats

Whereas some bird species are heavily affected by blood parasites in the wild, others reportedly are not. Seabirds, in particular, are often free from blood parasites, even in the presence of potential vectors. By means of polymerase chain reaction, we amplified a DNA fragment from the cytochrome b gene to detect parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus in 14 seabird species, ranging from Antarctica to the tropical Indian Ocean. We did not detect parasites in 11 of these species, including one Antarctic, four subantarctic, two temperate, and four tropical species. On the other hand, two subantarctic species, thin-billed prions Pachyptila belcheri and dolphin gulls Larus scoresbii, were found infected. One of 28 thin-billed prions had a Plasmodium infection whose DNA sequence was identical to lineage P22 of Plasmodium relictum, and one of 20 dolphin gulls was infected with a Haemoproteus lineage which appears phylogenetically clustered with parasites species isolated from passeriform birds such as Haemoproteus lanii, Haemoproteus magnus, Haemoproteus fringillae, Haemoproteus sylvae, Haemoproteus payevskyi, and Haemoproteus belopolskyi. In addition, we found a high parasite prevalence in a single tropical species, the Christmas Island frigatebird Fregata andrewsi, where 56% of sampled adults were infected with Haemoproteus. The latter formed a monophyletic group that includes a Haemoproteus line from Eastern Asian black-tailed gulls Larus crassirostris. Our results are in agreement with those showing that (a) seabirds are poor in hemosporidians and (b) latitude could be a determining factor to predict the presence of hemosporidians in birds. However, further studies should explore the relative importance of extrinsic and intrinsic factors on parasite prevalence, in particular using phylogenetically controlled comparative analyses, systematic sampling and screening of vectors, and within-species comparisons.

Infection by Haemoproteus Parasites in Four Species of Frigatebirds and the Description of a New Species of Haemoproteus (Haemosporida: Haemoproteidae)

Abstract: Among seabirds, the fregatids stand out with a high prevalence of blood parasites. Four of 5 species in this family have been found to be infected with Haemoproteus; however, complete species descriptions with molecular phylogeny are lacking. Seventy-five samples from 4 species of frigatebirds, i.e., Fregata andrewsi, Fregata minor, Fregata magnificens, and Fregata aquila, were screened for infections caused by species of Haemoproteus. Four different parasite haplotypes were found infecting frigatebirds based on the sequencing of a fragment of the cytochrome b gene. Two haplotypes belong to the subgenus Parahaemoproteus, and the other 2 correspond to haplotypes within the subgenus Haemoproteus. The more prevalent and cosmopolitan Parahaemoproteus haplotype (FregPHae1) was phylogenetically grouped with other Haemoproteus parasites infecting non-passerine birds, but it could not be detected from the single sample from F. aquila. The other Parahaemoproteus haplotype (FregPHae2) was not phylogenetically clustered with parasites infecting non-passerine birds, and it was sequenced from a single (1 each) F. andrewsi and F. minor. Blood smears from F. andrewsi infected only by FregPHae1 haplotype showed sufficient gametocytes to allow description of a new species, Haemoproteus valkiūnasi sp. nov. In contrast to Haemoproteus iwa, the only previously known blood parasite infecting frigatebirds and described from F. minor from Galapagos Islands, parasites from F. andrewsi (1) are shorter with no contact of gametocyte with host cell membrane, (2) have fewer pigment granules, and (3) have wider microgametocytes, with a smaller host nuclear displacement. In contrast, patent single infections corresponding to the cosmopolitan haplotype of the subgenus Haemoproteus (FregHae1) were also found in samples from 1 F. andrewsi, 1 F. minor, and 1 F. aquila. In all these cases, the number of microgametocytes was very low, resembling H. iwa, which lacks microgametocytes in the original description. Macrogametocytes of haplotype FregHae1 in F. andrewsi differ significantly from all the characteristics measured from H. valkiūnasi. In addition, it also differs from all characteristics of H. iwa despite being genetically identical in the analyzed fragment.

Storms and heat limit the nest success of Bank Cormorants: implications of future climate change for a surface-nesting seabird in southern Africa

AbstractThe Bank Cormorant Phalacrocorax neglectus is endemic to the Benguela Upwelling System of southern Africa. Most breeding colonies occur on offshore rocks, islands or man-made structures close to the high-water mark. Despite adaptations for breeding close to the water, nests can be lost to storms. Using data from two colonies where food is not considered limiting, we present a comparative study on nest survival in Bank Cormorants. Using a combination of the Mayfield method and parametric survival analysis, nest success was compared in nests on man-made structures at Robben Island, South Africa, where birds breed during the austral winter, with nests on man-made and natural structures at Mercury Island, Namibia, where Bank Cormorants breed during the austral summer. Overall, the probability of a nest surviving the breeding attempt was lower at Robben Island than at Mercury Island in all three seasons. Nest failures at Robben Island were related to wave heights and air temperature, with trends to suggest reduced chick survival in years where major storm events occurred during peak breeding. A heat wave appeared to cause major chick mortality at Mercury Island in 2005. Nest survival was relatively invariable between years at the main site monitored on Mercury Island, where nests were partially sheltered from the sun, but breeding productivity was poor in comparison to other cormorant species. Winter breeding in South Africa may increase the risk from storms but reduce the risk of heat exposure. An understanding of the impact of stochastic events on Bank Cormorants may be important in safe-guarding the continued survival of the species, particularly in light of the risks posed by future climate change.ZusammenfassungStürme und Hitze limitieren den Bruterfolg der KüstenscharbePhalacrocorax neglectus: Auswirkungen des Klimawandels auf einen nahe des Meeresspiegels brütenden Seevogel im südlichen Afrika Die Küstenscharbe Phalacrocorax neglectus ist endemisch für das Auftriebsgebiet des Benguela-Stroms im südlichen Afrika. Die meisten Brutkolonien befinden sich auf Felsen, Inseln und künstlichen Strukturen kurz über der Hochwassermarke. Trotz Anpassungen an das Brüten nahe der Wasserlinie werden Nester oft durch Stürme zerstört. In dieser Studie vergleichen wir den Bruterfolg der Küstenscharbe in zwei unterschiedlichen Kolonien, in denen keine Nahrungsknappheit vorliegt. Mit Hilfe der Mayfield-Methode und parametrischer Tests zur Berechnung der Überlebensrate wurden der Bruterfolg von Tieren auf Robben Island, Südafrika, und Mercury Island, Namibia verglichen. Auf Robben Island brüten die Tiere im dortigen Winter auf künstlichen Strukturen, während die Vögel auf Mercury Island während der Sommermonate sowohl auf natürlichen als auch auf künstlichen Strukturen brüten. In allen drei Untersuchungsjahren lag der Bruterfolg auf Robben Island unter dem von Mercury Island. Nestverluste auf Robben Island wiesen einen Zusammenhang mit Wellenhöhe und Lufttemperaturen auf und höhere Kükenverlusten wurden in Jahren beobachtet, in denen große Sturmereignisse mit der Hauptbrutperiode zusammenfielen. Eine Hitzewelle in 2005 verursachte ein großes Kükensterben auf Mercury Island. Der Bruterfolg schwankte nur gering auf Mercury Island in der Hauptbrutkolonie, wo Nester teilweise geschützt und im Schatten lagen. Im Vergleich zu anderen Kormoranarten war der Bruterfolg aber eher gering. Das Brüten im Winter bei Tieren in Südafrika verringert die Gefahr der Verluste durch Hitzwellen, erhöht aber die Gefahr von Nestverlusten durch Stürme. Ein besseres Verständnis der Einflüsse von stochastischen Wetterereignissen auf den Bruterfolg dieser bedrohten Art ist besonders wichtig in Hinblick auf den Klimawandel und damit einhergehenden Veränderungen im Wetter.

Processes influencing the population dynamics and conservation of African penguins on Dyer Island, South Africa

Dyer Island, South Africa, supported the largest African penguin Spheniscus demersus colony in 1979 (22 655 breeding pairs), but population dynamics of the species have not followed the trends of adjacent colonies in years of high fish abundance or shifts in prey distribution. Less than 1 500 pairs were breeding on Dyer Island in 2013. Available knowledge on demographic parameters was collated and ecological processes were quantified. Juvenile and adult survival probabilities estimated for birds ringed on Dyer Island between 2005 and 2011 were 0.247 (SE 0.06) and 0.545 (SE 0.05) respectively. Juveniles had a high probability (0.918; SE 0.077) of moving away from Dyer Island. Predation by seals and kelp gulls, as well as oiling, are currently important top-down pressures on penguins on Dyer Island. Numbers of birds breeding on the island were negatively correlated with purse-seine catches 20 nautical miles around it. However, it seems that once the colony size is <3 500 breeding pairs, the importance of fishing pressure diminishes, suggesting that once a colony has been reduced to a relatively small size, its growth is limited by pressures other than fishing. From the review of available knowledge presented here, we recommend a number of management options that should be tested in a suitable model.

Plasticity in foraging behaviour and diet buffers effects of inter- annual environmental differences on chick growth and survival in southern rockhopper penguins Eudyptes chrysocome chrysocome

In marine ecosystems, primary productivity and consequently food availability for higher trophic levels are often strongly affected by the water temperature. Thus, differences in sea surface temperatures (SST) may lead to differences in the diet composition of predators, but this link is still unknown in many species. By combining GPS tracking and dive analyses on chick-rearing southern rockhopper penguins (Eudyptes chrysocome chrysocome) with stable isotope analyses and monitoring of chick growth rates and chick survival, we here attempted a comprehensive assessment of the effects of inter-annual environmental variability as indicated by SST and chlorophyll a (reflecting primary productivity) data. Inter-annual differences in environmental variables around our study colony on New Island, Falkland/Malvinas Islands, contradicted the general expectation, with higher chlorophyll a concentrations coinciding with higher spring SST in 2010/2011 compared to 2009/2010. Penguins foraged further away from the colony during guard and crèche in 2010/2011 compared to 2009/2010, while performing deeper dives in 2009/2010. Stable isotope mixing models suggested a crustacean-dominated chick diet in 2009/2010, compared to a mixture of squid and fish in 2010/2011. These differences in foraging behaviour and diet, however, had no consequences for chick growth rates or chick survival and thus had no apparent effect on population trajectories. Potentially, environmental conditions in both years could still be seen as favourable compared to other years and breeding sites, enabling the parental birds to buffer the environmental differences by plastic foraging behaviour.

Novel vagrant records and occurrence of vector-borne pathogens in King Penguins (Aptenodytes patagonicus) in South Africa

The King Penguin (Aptenodytes patagonicus) is a pelagic seabird that breeds on Subantarctic islands and is considered a rare vagrant in South Africa. From 2001 to 2017, six King Penguins were rescued along the South African coast and admitted into rehabilitation centers. These and previous records of King Penguins were obtained near the country’s major ports, which suggests that some of these birds may have been ship-assisted. One of the King Penguins evaluated in this study died shortly after being admitted to the rehabilitation center due to extensive hemorrhage caused by a long-line fishing hook, and another had a beak wound consistent with fishing hook injury. Three King Penguins were infected with the tick-borne protozoan Babesia peircei and two died as a result of babesiosis. One King Penguin was diagnosed with an infection by Rickettsia-like organisms. Pox-like lesions, presumably mosquito-borne, developed on the eyelid skin of one penguin. Additionally, one of two King Penguins permanently captive in Cape Town during the same period also presented a lethal case of spirochetosis, which was possibly tick-borne. These novel records of vector-borne pathogens in King Penguins highlight the risk of seabird rehabilitation centers to serve as potential sources of pathogens to vagrant species, while also illustrating the opportunities that these centers provide for pathogen research and surveillance.