Hans-Ulrich Peter

Phylogeography of the southern skua complex-rapid colonization of the southern hemisphere during a glacial period and reticulate evolution.

Whilst we have now a good understanding how past glaciation influenced species at the northern hemisphere, our knowledge of patterns and modes of speciation is far more limited for the southern hemisphere. We provide mtDNA based data on the phylogeography of a circumpolar distributed southern hemisphere seabird group-the southern skua complex (Catharacta spp.). Diversification of southern skuas dates between 210,000 yBP and 150,000 yBP and coincides with a glacial spanning 230,000-140,000 yBP. Skuas most likely first inhabited the Antarctic continent, in the course of global cooling and increasing glaciation spread to the sub-antarctic islands and Tristan da Cunha and finally colonized Patagonia and the Falkland Islands at the glacial maximum. Despite significant differences between taxa most populations still exchange genes with neighboring populations of other taxa and speciation is incomplete.

Vocal performance reflects individual quality in a nonpasserine

Recent studies on mate-quality recognition in passerines showed that females use subtle differences in sound production to assess males. We analysed long calls of brown skuas, Catharacta antarctica lonnbergi, to test whether vocal performance could serve as an indicator of individual quality in a nonpasserine species. Measurements of vocal performances focused on two acoustic parameters for which motor constraints have been reported in passerines, namely ‘vocal deviation’ and ‘peak performance’. As potential indicators of individual quality we measured body size, body condition (body mass corrected for size) and mean reproductive success. We found a triangular distribution of calls between note repetition rate and frequency bandwidth. Males performing long calls closer to the performance limit had a higher mean reproductive success than males that show long calls with a larger vocal deviation. Similarly, males calling with a high peak performance were more successful breeders than males with low peak performance. Our findings indicate that long calls of brown skuas are limited by motor constraints similar to vocalizations in passerines. We show that differences in vocal performance reflect males reproductive success with more successful breeders producing the more difficult calls. This implies that limits on vocal performance due to motor constraints present a suitable mechanism for mate-quality recognition in nonpasserine birds.

Environmental monitoring and management proposals for the Fildes Region, King George Island, Antarctica

The Antarctic terrestrial environment is under increasing pressure from human activities. The Fildes Region is characterized by high biodiversity, but is also a major logistic centre for the northern Antarctic Peninsula. Different interests, from scientific research, nature conservation, protection of geological and historical values, station operations, transport logistics and tourism, regularly overlap in space and time. This has led to increasing conflict among the multiple uses of the region and breaches of the legal requirements for environmental protection that apply in the area. The aim of this study was to assess the impacts of human activities in the Fildes Region by monitoring the distribution of bird and seal breeding sites and recording human activities and their associated environmental impacts. Data from an initial monitoring period 2003–06 were compared with data from 2008–10. We observed similar or increased levels of air, land and ship traffic, but fewer violations of overflight limits near Antarctic Specially Protected Area No. 150 Ardley Island. Open waste dumping and oil contamination are still major environmental impacts. Scientific and outdoor leisure activities undertaken by station personnel are more frequent than tourist activities and are likely to have a commensurate level of environmental impact. Despite the initial success of some existing management measures, it is essential that scientific and environmental values continue to be safeguarded, otherwise environmental impacts will increase and the habitat will be further degraded. We argue that the Fildes Region should be considered for designation as an Antarctic Specially Managed Area, a measure that has proven effective for environmental management of vulnerable areas of the Antarctic.

Provisioning and growth in chicks of Wilson's storm-petrels (Oceanites oceanicus) on King George Island, South Shetland Islands

Abstract We present data on chick growth and chick feeding in Wilsons storm-petrel (Oceanites oceanicus) in a colony on King George Island, South Shetland Islands. Chicks were repeatedly weighed and the weight differences over 24 h were corrected for metabolic loss in order to obtain an estimation of meal sizes. Chicks were fed on 93% of the nights (n=688 nights). The average meal size for a single feeding was 8.5 g. Chicks received on average 1.2 feedings per night. These results are compared with data for this species from other locations. There was a trend for increased meal sizes from northern to southern populations, parallel to an increase in the adult mass, indicating that Wilsons storm-petrels carry optimal meal sizes according to their body size and may take advantage of increased food abundance by increasing feeding frequencies. We describe chick growth and discuss the influence of egg size, hatching date and feeding frequency on chick growth. The egg size had a positive influence on tarsus growth and body mass of chicks. Later-hatched chicks started wing growth and finished mass growth at a younger age and reached lower peak masses, indicating that late chicks may adapt to the restricted breeding season in their Antarctic breeding grounds by a more rapid development, but will fledge with a lower degree of development and less resources.

Factors affecting chick growth in the South Polar Skua (Catharacta maccormicki): food supply, weather and hatching date

This study investigated chick growth in a pelagic Antarctic seabird, the South Polar Skua (Catharacta maccormicki). The factors food supply, weather and hatching date were analysed in a population of 54 breeding pairs at King George Island/South Shetland Islands. Food supply was manipulated by offering fish corresponding to 20% of daily energy demand of chicks to half of the breeding pairs every second day. Growth of mass, head, wing and tarsus was followed and related to the treatment, weather conditions, hatching date and interactive effects. Food supply did not limit chick growth in the studied season. Parents seemed to try to feed their chicks at a maximum rate and succeeded in the studied season because the general food supply was very good. Low temperatures and strong winds depressed chick growth. A growth advantage of food-supplemented chicks could be observed when the natural conditions for chick growth were sub-optimal. Chick growth rate was strongly negatively associated with hatching date and worsening weather during the reproductive season could be excluded as explanatory variable for this finding.

Assessing trace element contamination in Fildes Peninsula (King George Island) and Ardley Island, Antarctic

King George Island, situated in the South Shetland Islands archipelago, is one of the most visited sites in Antarctica. This has contributed to a high density of scientific stations and shelters in the region, especially in Fildes Peninsula. In order to evaluate the natural and anthropogenic sources of trace elements (As, Cd, Cu, Zn, Pb and Hg) soil and moss samples were collected from different sites in January 2013. In general, the results revealed homogeneous concentrations (μgg(-)(1)) for each element in the majority of collected samples (As: 3.8±1.4; Cd: 0.4±0.9; Cu: 34±4; Zn: 115±13; Pb: 20±5; Hg; 0.011±0.009). However, some samples in specific areas of Fildes Bay showed the existence of local anthropogenic activities that have contributed to the enrichment of contaminants in soils and moss samples that correlated to one another (e.g. Pb: 1101μgg(-)(1)). Human presence is linked to examples of contamination and environmental perturbation, making essential the implementation of this type of study in order to understand and protect unique places in Antarctica.

Chick provisioning and nest attendance of male and female Wilson’s storm petrels Oceanites oceanicus

Seabirds show a range of patterns of sexual size dimorphism and sex-specific parental investment, but the underlying causes remain poorly understood. The aim of the present study was to test two longstanding hypotheses of parental investment in a sexually monomorphic species, Wilson’s storm petrel Oceanites oceanicus, namely that males attend chicks more frequently and females deliver larger meals (Beck and Brown in Br Antarct Surv Sci Rep 69:1–54, 1972). We recorded in eight seasons, both during incubation and chick rearing, which adult was caught first in a nest and found no difference in the probability of catching a male or a female first in any year. Additionally, in five seasons we employed a miniature video camera to record nest attendance during chick rearing and found no significant difference except for 2006, a year with very low krill availability, where females visited the nest less often than males. We then combined video observations with periodic weighing of chicks to estimate mean daily feeding mass (g/day) of males and females and found no difference in the amount of food delivered per day between the sexes. However, in years with low krill availability, males and females tended to use different strategies to achieve the same feeding rates, with females undertaking longer foraging trips and delivering heavier meals. Thus, our results do not support the hypothesis of a general sex-specific parental investment in Wilson’s storm petrels, but a tendency for a context-dependent sex-specific investment in the years of food shortage.

A hitherto unknown hybridization between Chilean and South Polar skua

Abstract Three skua specimens with a colouration pattern of the Chilean skua were observed at Potter Peninsula, King George Island, Antarctica. Two of these were breeding birds. However, they showed a pattern of mitochondrial DNA typical for South Polar skua. These birds thus represent hybrids originating from male Chilean skua. The third bird could not be caught. It appeared to be indistinguishable from Chilean skua.

Environmental Assessment and Management Challenges of the Fildes Peninsula Region

Since the inception of the Antarctic Treaty, numerous regulations for environmental protection were adopted by the Treaty parties to minimise negative environmental impacts of human activity. Nevertheless, the concentration of a variety of human activities in some Antarctic regions leads to a conflict of interest. The Fildes Peninsula on King George Island, in the Antarctic Peninsula, represents a unique example of increasing human pressure due to multiple human uses. Scientific research, station operations, transport logistics, tourism, nature conservation and protection of geological and historical values regularly overlap in space and time. A standardised assessment of fauna, flora and impact of human activities on the terrestrial ecosystem was conducted between 2003–2006 and 2008–2011 to provide a comprehensive dataset that documents the environmental state of the Fildes Peninsula. Management measures are suggested to mitigate these impacts, such as the designation of an Antarctic Specially Managed Area. The political debate amongst the Treaty parties about regulatory measures is on-going, but we strongly recommend immediate action.

Seabird diversity hotspot linked to ocean productivity in the Canary Current Large Marine Ecosystem

Upwelling regions are highly productive habitats targeted by wide-ranging marine predators and industrial fisheries. In this study, we track the migratory movements of eight seabird species from across the Atlantic; quantify overlap with the Canary Current Large Marine Ecosystem (CCLME) and determine the habitat characteristics that drive this association. Our results indicate the CCLME is a biodiversity hotspot for migratory seabirds; all tracked species and more than 70% of individuals used this upwelling region. Relative species richness peaked in areas where sea surface temperature averaged between 15 and 20°C, and correlated positively with chlorophyll a, revealing the optimum conditions driving bottom-up trophic effects for seabirds. Marine vertebrates are not confined by international boundaries, making conservation challenging. However, by linking diversity to ocean productivity, our research reveals the significance of the CCLME for seabird populations from across the Atlantic, making it a priority for conservation action.