Five species of cormorants breed along the Argentinean coast: Imperial Shag (Phalacrocorax atriceps), Rock Shag (Phalacrocorax magellanicus), Red-legged Shag (Phalacrocorax gaimardi), Neotropic ...Cormorant (Phalacrocorax olivaceus) and Guanay Shag (Phalacrocorax bougainvillii). The state of nowadays knowledge, including unpublished information, on different aspects of biology, ecology, abundance and distribution of cormorants populations in the Argentinean coast, is presented. The effects and conflicts that the main human activities (oil transportation, guano exploitation, tourism and interaction with fisheries) have on cormorants populations in the Argentinean Patagonia, are analyzed. Recommendations for future scientific studies to improve cormorant management and conservation are presented as the final conclusion.
Red-legged Cormorants Phalacrocorax gaimardi breed in Argentina, Chile, and Peru. In Argentina their breeding range is restricted to a short section of coastline in southern Patagonia. We studied two ...colonies located on high rocky cliffs, 2 to 4 m above the high tide line. At one colony, nests were protected from prevailing winds whereas at the other colony most of the nests were exposed. Of active nests, 15% had two eggs, 66% had three eggs, and 19% had four eggs, to give a mean clutch size of 3.04 plus or minus 0.47. Egg dimensions were 60.3 plus or minus 2.4 x 37.1 plus or minus 1.4 mm. The incubation period ranged from 34 to 38 days with chicks hatching from mid-November to the first week of December. Red-legged Cormorants lay more and smaller eggs than do those of two sympatric cormorant species, the Rock Cormorant P. magellanicus and the Imperial Cormorant P. atriceps, probably as a result of differences in foraging ranges. Avian predation on eggs seems to be an important mortality factor for this species and wind has also an important effect on breeding success, possibly exacerbating avian predation.
An upper bound for the “sausage catastrophe” of dense sphere packings in 4-space is given. A basic problem in the theory of finite packing is to determine, for a given positive integer k, the minimal ...volume of all convex bodies into which k translates of the unit ball Bd of the Euclidean d-dimensional space Ed can be packed (5). For d = 2 this problem was solved by Groemer (6).
The distribution and abundance of Red-legged Cormorants (Phalacrocorax gaimardi) were assessed by visiting 42 localities on the mainland and surveying most of the islands along Peru’s 2,500 km ...coastline between October 1999 and December 2000. Cormorants were distributed in small discrete groups (Mode = 5 birds, range 1-69) from Isla Foca (5°12’S) to Morro Sama (18°0’S). The southern (56% of the total numbers) and central (34%) coast held a larger proportion of cormorants than did the northern region (10%). Birds were mainly located in unprotected areas, either on islands (6%) or on the mainland (51%). The remainder was found in protected areas, either guano bird islands (27%), guano bird headlands (3%) or within the Paracas Reserve (13%). We counted 658 birds (95% adults, 5% juveniles), but based on bird density, availability of suitable habitats and cliff lengths we predicted a total of 1,803 ± 282 birds in Peru. Red-legged Cormorants built their nests on narrow ledges on vertical rocky walls falling sheer to the sea, located, on average, 17.8 m (range = 3-50, N = 56) above the sea level on open cliffs, high-up in sea cave entrances or on small islets. They have undergone a spectacular decline over the last 30 years. Between 1968 and 1999-2000, the numbers at ten localities in the northern and central coast decreased from 3,229 to 69 birds. It is likely that low numbers recorded in this study reflect the devastating effects of the strong El Niño Southern Oscillation (ENSO) of 1997-98, as numbers prior and after this event at eight southern localities decreased by 73%. Because of the inaccessibility of their nesting and roosting sites and the lack of natural predators, Red-legged Cormorants are apparently not in danger at such sites. However, entanglement in fishing nets, competition for food in inshore waters, pollution, human disturbance and harvesting of kelp banks are potential threats at sea and could affect the population recovery.
Male and female Rock Shags (Phalacrocorax magellanicus) are not obviously sexually dimorphic in plumage or size and are thus difficult to distinguish in the field. We evaluated the utility of two ...different DNA-based techniques for sexing adult Rock Shags. We found that the primer set 2550F/2718R (originally tested in three individuals of P. carbo), with minor differences in the forward primer, provided a consistent and simple sexing method for Rock Shags. Moreover, we obtained three reliable discriminant functions for sexing adults from three different colony sites between 42 degree to 47 degree S in coastal Patagonia, Argentina. Discriminant analysis of five external characters of adult birds indicated that head, bill, and wing lengths were the most accurate variables for use in a discriminant function model, predicting the sex of 80-86% of the birds. Males were significantly larger than females for all body measurements except for bill depth. Rock Shags showed less marked sexual dimorphism than other phalacrocoraciid species.Original Abstract: Determinacion del sexo en Phalacrocorax magellanicus utilizando metodos moleculares y parametros morfometricos perpendicular o existe dimorfismo sexual obvio en plumaje o tamano entre machos y hembras de Phalacrocorax magellanicus, y por lo tanto es dificil distinguir el sexo en el campo. Evaluamos la utilidad de dos tecnicas diferentes basadas en el DNA para determinar el sexo en adultos de esta especie. Hallamos que el primer 2550F/2718R (originalmente probado en tres individuos de P. carbo), con pequenas diferencias en el 'primer' delantero, resulto ser un metodo consistente y simple para determinar el sexo en Phalacrocorax magellanicus. Ademas, obtuvimos tres funciones discriminantes confiables para hallar el sexo en adultas de tres colonias distintas en las costas de Patagonia, Argentina entre 42 degree S y 47 degree S. Analisis discriminantes de cinco caracteres externos de aves adultas indicaron que el largo de la cabeza, pico y alas fueron las variables mas precisas a usarse en un modelo de funciones discriminantes, prediciendo el sexo de un 80-86% de las aves. Los machos fueron significativamente mayores que las hembras para todas las medidas corporales excepto para la profundidad del pico. Esta especie mostro tener un dimorfismo sexual marcadamente menor que otras especies congenericas.
The behaviour of Magellanic Penguins Spheniscus magellanicus commuting between their foraging areas and breeding areas in San Julian Bay, Argentina was studied to examine whether tidal rip currents ...affected travelling patterns. Although there was no apparent relationship between departure and arrival patterns and the state of the tidal cycle, birds travelling against the current dived for longer periods and had shorter rests on the surface than birds travelling with the current. In addition, birds swimming against the current hugged the banks of tidal rivers much more closely than did birds swimming with the current, thus reducing the magnitude of the current against which they had to swim. In cases of extremely high current speeds, birds travelling upstream walked. Models regarding the energetics of movement indicate that the strategies adopted by Magellanic Penguins can result in substantial energy savings.
As part of annual colony counts in Santa Cruz Province, Argentina, a health survey of rockhopper penguins (Eudyptes chrysocomes) was conducted in 1994. Forty-five birds were examined during handling ...procedures, and blood and fecal samples were collected for laboratory analysis. All birds appeared to be in good condition. No ecto- or endoparasites were found. Hematology, plasma chemistry, and plasma mineral levels were measured and correlated with the results of bacterial and viral serology. Antibodies against Chlamydia sp., avian adenovirus, avian encephalomyelitis virus, infectious bronchitis virus, avian reovirus, and paramyxovirus-1, -2, and -3 were found. Mean plasma chemistry and mineral values differed between individuals testing positive and negative on serologic tests. There was no serologic evidence of exposure to avian influenza virus, duck viral enteritis, infectious bursal disease, infectious laryngotracheitis, Aspergillus sp., or Salmonella pullorum. Trace amounts of endrin were found in the plasma of one bird, but all other chlorinated pesticide and polychlorinated biphenyl levels were below detectable limits.
Three penguin species breed along the coasts of Argentina (SW Atlantic): the Magellanic Penguin (Spheniscus magellanicus), the Rockhopper Penguin (Eudyptes chrysocome) and the Gentoo Penguin ...(Pygoscelis papua). The King Penguin (Aptenodytes patagonica) historically bred at de los Estados Island (Argentine Sea), and one individual was recently recorded there incubating an egg. The available information on the distribution and the population status of these penguin species is reviewed. A synthesis of the information on the breeding cycle, the feeding ecology and habitat requirements for the Magellanic Penguin and the Rockhopper Penguin, and an evaluation of their interactions with human activities and current conservation status, is presented. The review focuses on aspects that are relevant to the development of monitoring programmes, action plans and regional conservation strategies. Finally, a list of research, conservation and management recommendations is given.
The HeRSCheL detector consists of a set of scintillating counters, designed to increase the coverage of the LHCb experiment in the high-rapidity regions on either side of the main spectrometer. The ...new detector improves the capabilities of LHCb for studies of diffractive interactions, most notably Central Exclusive Production. In this paper the construction, installation, commissioning, and performance of HeRSCheL are presented.
