At-sea abundance and distribution of skuas and jaegers (Charadriiformes: Stercorariidae) at coastal waters off central Chile

Indexación: Web of Science; Scielo.BACKGROUND: Skuas and jaegers (Charadriiformes: Stercorariidae) are seabirds breeding at moderate to high latitudes and some perform extensive post-breeding transequatorial migrations. Most species overwinter and perform significant portions of their migratory flyways along the Pacific coast of South America, but scant information is available on their at-sea ecology in this waters. Our aims in this study were to determine: 1) the timing of occurrence and fluctuations in abundance of skua and jaeger species, 2) their spatial distribution within the coastal zone and 3) at-sea behavior of birds, including flock size and interactions with other seabird species. RESULTS: Between July 2006 and October 2013, we conducted at-sea bird counts at Valparaiso Bay (33°S) in central Chile and confirmed the occurrence of Chilean skuas (Stercorarius chilensis), Brown skuas (S. antarcticus), and Parasitic jaegers (S. parasiticus). Parasitic jaegers are regular austral summer visitors (November to March), whereas Brown skuas occur in the area only in winter (July to October). Chilean skuas were regularly recorded year-round in the area with higher abundances between late winter and early spring (August to October). Brown and Chilean skuas where observed comparatively offshore, whereas Jaegers presented a more coastal distribution, probably associated to host presence. Chilean skuas kleptoparasitized similar-sized (shearwaters and fulmars) and larger seabird species (boobies), whereas jaegers chased only smaller coastal birds (gulls and terns). Brown skuas engaged in no kleptoparasitic behaviors. All three species were observed mostly as solitary individuals. CONCLUSIONS: Skuas and jaegers showed in general a marked seasonality in their occurrence and abundance (only Chilean skua occurs year-round) and use this area as a commuting and stopover zone within their extensive migratory flyway along the southeastern Pacific.http://ref.scielo.org/p7thp

Humboldt penguins monitored via VHF telemetry

VHF telemetry was used in November and December 1995 on 8 Humboldt penguins Spheniscus humboldti breeding at Pan de Azúcar Island (26°S, 70°W), Northern Chile, to determine at-sea behaviour of the birds. We obtained 2710 locations, 90% of which were within a radius of 20 km around the island. Mean travelling speed of the birds was 0.92 m s-1 and speed distribution showed peaks at 1.6 and 3 m s-1. Penguins travelling between foraging areas remained submerged for an average of 8.4 s between surfacings, whereas foraging dives lasted on average 61 s. The analysis of 79 complete foraging trips showed that tracks deviated from a straight course, and range (maximum distance from island) was only 0.37 times total horizontal distance swum. Birds did not forage synchronously or in the same foraging areas. However, foraging ranges were correlated between birds, indicating similar search strategies during periods of low food availability. The results obtained here via VHF telemetry agreed well with those of previous studies employing satellite transmitters and data loggers

BREEDING OF THE SOUTH AMERICAN TERN (STERNA HIRUNDINACEA) ON ANCHORED BOATS IN COQUIMBO, NORTHERN CHILE

Abstract · We report the breeding attempt of South American Terns (Sterna hirundinacea) on three boats in Coquimbo, northern Chile. The first breeding attempt was reported in winter 2011 where at least one chick fledged. From April to June 2015, all nests on the boats were monitored. We recorded eggs and chicks during May and early June. However, towards the end of June, no eggs or chicks were recorded in the nests, and a Chimango Caracara (Phalcoboenus chimango) was observed preying on chicks in one nest. In April and May 2017, breeding attempts on boats were also monitored and nests with eggs and one chick were recorded. However, at the end of May all nests were empty. This unusual nesting site for South American Terns is apparently regularly used in the area despite its virtually null breeding success. Resumen · Reproducción del Gaviotín Sudamericano (Sterna hirundinacea) en botes anclados en Coquimbo, norte de Chile Reportamos el intento de reproducción del Gaviotín Sudamericano (Sterna hirundinacea) sobre tres botes en Coquimbo, norte de Chile. Un primer intento de reproducción para esta zona se registró en invierno de 2011, donde al menos un pollo dejó un nido como volantón. Entre Abril y Junio de 2015 monitoreamos los nidos en los botes de manera más intensiva. Registramos huevos y pollos durante Mayo y principios de Junio. Sin embargo, a finales de Junio, no registramos huevos en los nidos y observamos un Tiuque (Phalcoboenus chimango) depredar sobre los pollos. En Abril y Mayo de 2017, monitoreamos otros intentos de reproducción y registramos un pollo y nidos con huevos. Sin embargo, a finales de Mayo, esos nidos estaban vacíos. Este inusual sitio de nidificación parece ser utilizado de forma recurrente por el Gaviotín Sudamericano, a pesar del aparente casi nulo éxito reproductivo

Foraging ecology of masked boobies (Sula dactylatra) in the world’s largest “oceanic desert”

The South Pacific Gyre has the most hyper-oligotrophic waters in the world and is considered the largest “oceanic desert.” Rapa Nui (Easter Island), located within the South Pacific Gyre, is a breeding ground for masked boobies (Sula dactylatra), which are seabirds with a foraging range that effectively confines them within the gyre. The foraging ecology of this species in the gyre was examined by attaching GPS and time-depth devices to chick-rearing adult birds (9 and 14 birds in 2016 and 2017, respectively) and by collecting regurgitates (18 and 15 samples in 2016 and 2017, respectively). In addition, the birds’ foraging ecology between years was compared. Masked boobies traveled in various directions, dived at unspecific locations, and explored areas < 110 km from the colony. Local environmental conditions were not significantly different between years, and differences in foraging parameters (maximum foraging range, trip duration, and dive depth) were greater among individuals than between years. The foraging characteristics of masked boobies suggest that resources were ephemerally distributed around the colony, with similar abundances across years. Under these conditions, traveling to unspecific locations may increase the area covered and the probability of prey encounter. The spatial and temporal consistencies in environmental conditions explain the uniformity of foraging parameters between years. The ability of masked boobies to exploit ephemerally distributed resources in seascapes like Rapa Nui may help explain its pantropical distribution

Seabird distribution on the Humboldt Current in northern Chile in relation to hydrography, productivity, and fisheries

Factors affecting seabird distribution in the Humboldt Current upwelling system in northern Chile were studied in January 1999 using ship transect counts. Of 24 species recorded, the Peruvian booby (Sula variegata), the kelp gull (Larus dominicanus) and the Humboldt penguin (Spheniscus humboldti) were the most abundant. Species composition varied among different areas of the system and distribution patterns differed substantially among eight of the more abundant species. Most species showed links to variation in environmental factors (trawler distribution, SST and chlorophyll concentration). Principal component analysis identified a feeding-flock factor as the most important one for explaining observed distribution patterns. One-third of all birds recorded were associated in feeding flocks and 3% of all individuals were directly attending fishing vessels

In search for the sources of plastic marine litter that contaminates the Easter Island Ecoregion

Subtropical gyres are the oceanic regions where plastic litter accumulates over long timescales, exposing surrounding oceanic islands to plastic contamination, with potentially severe consequences on marine life. Islands’ exposure to such contaminants, littered over long distances in marine or terrestrial habitats, is due to the ocean currents that can transport plastic over long ranges. Here, this issue is addressed for the Easter Island ecoregion (EIE). High-resolution ocean circulation models are used with a Lagrangian particle-tracking tool to identify the connectivity patterns of the EIE with industrial fishing areas and coastline regions of the Pacific basin. Connectivity patterns for “virtual” particles either floating (such as buoyant macroplastics) or neutrally-buoyant (smaller microplastics) are investigated. We find that the South American shoreline between 20°S and 40°S, and the fishing zone within international waters off Peru (20°S, 80°W) are associated with the highest probability for debris to reach the EIE, with transit times under 2 years. These regions coincide with the most-densely populated coastal region of Chile and the most-intensely fished region in the South Pacific. The findings offer potential for mitigating plastic contamination reaching the EIE through better upstream waste management. Results also highlight the need for international action plans on this important issue

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to &lt;90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], &gt;300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of &lt;15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P&lt;0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P&lt;0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Efecto de la edad y la localidad en la concentración de cadmio y cobre en el hígado de la gaviota dominicana Larus dominicanus

We analyzed Cu and Cd liver concentration in adults and fledglings of Kelp gull from an urban (Coquimbo city) and a wild (Pájaros Islet) colony. Cu concentration was 15.57 ± 0.079 µg g-1 dry weight for adults and fledglings of both colonies. Adults Cd concentration from both colonies was 9.72 ± 0.110 µg g-1 dw, being 194% of the level considered toxic but in the range for seabirds. In the urban fledglings Cd was below the detection level. Wild fledgling showed higher concentration of 1.54 ± 0.064 µg g-1 dw which probably reflects a biomagnification process, because parents kleptoparasite and consume eggs and chicks of other seabirds