Verónica L. D'Amico

Exposure of Red Knots (Calidris canutus rufa) to Select Avian Pathogens; Patagonia, Argentina

As part of the shorebird surveillance, Red Knots (Calidris canutus rufa) were sampled in two Patagonian sites in Argentina, Río Grande and San Antonio Oeste, during 2005–2006. Cloacal swabs and serum samples were collected from 156 birds and tested by virus isolation (Newcastle disease virus), polymerase chain reaction (PCR; avian influenza virus and Plasmodium/Hemoproteus), and for antibodies to St. Louis encephalitis virus. All test results were negative.

Leucocyte Levels in Some Antarctic and Non-Antarctic Penguins

Summary. We studied leucocyte levels in several Antarctic and non-Antarctic penguins. A total of 107 blood samples of chinstrap Pygoscelis antarctica, gentoo P. papua and Adélie P. adeliae penguins at Isla 25 de Mayo/King George Island (South Shetland Islands, Antarctica) and Magellanic penguins Spheniscus magellanicus at Península Valdés (Chubut, Argentina), were collected and analysed during the 2009–2010 breeding season. We observed that chinstrap and Adélie penguins had lower total leucocyte counts than Magellanic and gentoo penguins. We provide some potential explanations for species differences in leucocyte levels.

Hematologic and Plasma Biochemistry Values for Endangered Red Knots (Calidris canutus rufa) at Wintering and Migratory Sites in Argentina

We obtained hematologic and plasma biochemistry values for adult, long-distance migrant Red Knots at their southernmost wintering site in Río Grande (Tierra del Fuego, Argentina) and at the first stopover site in San Antonio Oeste (Río Negro, Argentina). Lymphocytes (L) followed by heterophils (H) were the most abundant leukocytes. H/L ratio and glucose levels were significantly higher at Río Grande, possibly because of the stress of migration and molting. Packed cell volume results ranged widely, probably in response to increased oxygen demand for migration. Protein profiles and lipids were higher at the stopover site and attributable to birds storing reserves for subsequent flights.

Gastrointestinal helminths of Adélie penguins ( Pygoscelis adeliae ) from Antarctica

Knowledge about parasitic organisms in Antarctica is scarce and fragmentary. The study reported here adds to the knowledge of gastrointestinal parasites of the Adélie penguin (Pygoscelis adeliae) (Sphenisciformes), from 25 de Mayo/King George Island (South Shetlands), Bahia Esperanza (Hope Bay) and Avian Island (Antarctica). Thirty-five freshly dead specimens (20 chicks and 15 adults) were collected from December 2007 to December 2014 and examined for internal macroparasites. Three adult parasite species were found: one Cestoda, Parorchites zederi, and two Nematoda, Stegophorus macronectes and Tetrameres sp. Immature Tetrabothrius sp. were found in hosts from Avian Island. Helminth communities are known to be related to host feeding behaviours. Low parasite richness observed in Adélie penguins could be related to the stenophagic and pelagic diet of this host species, which feeds almost exclusively on krill.

Physiologic Parameters and their Response to Handling Stress in a Neotropical Migratory Shorebird During the Nonbreeding Season

Abstract Physiologic traits are promising indicators of population health in the face of rapidly changing environments. We obtained values of diverse physiologic parameters for Two-banded Plovers (Charadrius falklandicus) in coastal sites in Patagonia, Argentina, with the objectives of determining the timeline in which these parameters become affected by the stress of capture and handling and of obtaining reference values for future monitoring of these populations. We analyzed packed cell volume, white blood cell profile, heterophil/lymphocyte ratio, bacterial agglutination titer, and total protein, glucose, triglyceride, and cholesterol levels in apparently healthy birds. Glucose, total white blood cell count, lymphocytes, and eosinophil levels showed changes with handling times >60 min after capture. The remaining parameters did not manifest significant alterations in response to capture and handling of up to 232 min (average=105.2, SD=56.7). Therefore, although researchers should attempt to obtain blood samples as soon as possible after capture, inclusion of physiologic parameters in monitoring studies of species not easily sampled in a few minutes, such as Two-banded Plovers and other shorebird species during migration, should not be discouraged. Here we provide a physiologic report for the species that can be considered as reference values during the nonbreeding season at Patagonian coastal sites.

MODE OF ATTACHMENT AND PATHOLOGY CAUSED BY PARORCHITES ZEDERI IN THREE SPECIES OF PENGUINS: PYGOSCELIS PAPUA, PYGOSCELIS ADELIAE, AND PYGOSCELIS ANTARCTICA IN ANTARCTICA

Abstract We identified and compared gross and microscopic lesions associated with the cestode, Parorchites zederi, in the digestive tracts of three species of penguins (Spheniscidae): the Chinstrap (Pygoscelis antarctica), Gentoo (Pygoscelis papua), and Adélie penguins (Pygoscelis adeliae). The gastrointestinal tracts of 79 recently dead individuals (71 chicks and eight adults) were collected in locations throughout the Antarctic Peninsula during summer field trips in 2006–09. Parorchites zederi was found in the small intestine of 37 animals (47%), and 23 (62%) of these had parasite-associated lesions. The cestodes were either free in the intestinal lumen, clustered within mucosal ulcers, or deeply embedded in the intestinal wall. Histopathologic changes were most severe in adult Gentoo Penguins and included transmural fibrogranulomatous enteritis, hemorrhage, and edema. This report of pathology associated with P. zederi in the digestive tracts of penguins can serve as reference to monitor health in Antarctic birds associated with environmental changes.

Reverse Movements of Red Knots Calidris canutus During Northward Migration in Argentina

SUMMARY. Migratory birds are sometimes known to make reverse movements to seek better fuelling sites before undertaking long-distance migratory flights across ecological barriers. Red knots Calidris canutus rufa regularly make prodigious migratory flights of ∼ 8,000 km from southern South America to North America; these flights depend critically on the birds being able to store adequate fuel at southern staging sites. Knots staging at San Antonio Oeste (SAO) in northern Patagonia in Argentina could potentially backtrack ∼200 km southwards to complete refuelling at Península Valdés (PV). We therefore analysed resightings of birds individually marked in SAO or the flyway at these two staging sites in 2006, 2007, 2009 and 2010 to investigate whether reverse movements occurred between them. In the four-year period, 63 detected individuals backtracked south from SAO to PV in one or more years. These movements occurred in all years of the study thus demonstrating the annual occurrence of flights of ∼200 km in the opposite direction to the normal northward migration. There was no significant difference in body condition (mass), sex or day of first sighting in SAO between birds that made or did not make reverse movements to PV. However, individuals (N = 11) that backtracked to PV from SAO had significantly lower hematocrit levels at the time of capture than SAO resident birds (N = 205). Because migrating shorebirds have been shown to restore low hematocrit levels before undertaking rapid fuel storage to power long flights, we hypothesise that red knots backtracking to PV were probably behind schedule on migration, and thus may have traded-off the small cost of a ∼200 km flight for the increased foraging time and high quality soft-shell prey available late in the season at PV. This hypothesis helps to explain the later staging phenology of red knots using PV, and its role as an alternative staging area in the northward migration.

Evaluation of Physiological Parameters of Kelp Gulls (Larus dominicanus) Feeding on Fishery Discards in Patagonia, Argentina

Abstract. Physiological parameters provide relevant information on the general physical condition of freeliving birds. Blood parameters related to immune function, nutrition, and oxidative stress of Kelp Gulls (Larus dominicanus) that use fishery waste sites as feeding sites are reported. The presence of zoonotic bacteria in cloacal swabs was also assessed. Ranges of hematocrit, total proteins, glucose, and leukocyte counts were similar to those reported for other gull species and healthy birds in general. Heterophil and lymphocyte percentages were the only parameters affected by handling time of the birds. Reports of bacterial agglutination as an index of humoral innate immunity and oxidative stress makers are the first for the species. Kelp Gulls showed infection prevalence of 60% with Corynebacterium sp. and 30.5% with enteropathogenic Escherichia coli. Data presented here constitute a valuable contribution for future comparative studies and as baseline for clinical work.

FLOCKING BEHAVIOUR DOES NOT FAVOUR HIGH CHEWING LICE LOAD IN SHOREBIRDS

Summary. Flocking behaviour does not favour high chewing lice load in shorebirds. As shorebirds show a high variability in the flocking behaviour among species from solitary ones to species forming flocks of hundreds of individuals, they offer a good opportunity to test if the proximity of individuals in highly gregarious species increases the risk of horizontal ectoparasite transmission in comparison with solitary species. We investigate whether there exists a higher ectoparasite load in gregarious shorebirds compared to solitary ones at Salinas del Cabo de Gata, Almeria, Spain. Seven species of shorebirds (Scolopacidae and Charadriidae) were captured with mist-nets during the night. Ectoparasites were estimated by means of visual examination of seven body regions and differentiated in five levels of infestation. Flock size was divided into three categories: solitary species, species forming flocks up to 99 individuals and species forming flocks of more than one hundred. Based on the application of a phylogenetic comparative method, our results show that the abundance of chewing lice is not related with flocking behaviour.