Larus michahellis

Toxoplasma gondii infection in seagull chicks is related to the consumption of freshwater food resources

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Cabezón, O., Cerdà-Cuéllar, M., Morera, V., García-Bocanegra, I., González-Solís, J., Napp, S., Ribas, M.P., Blanch-Lázaro, B., Fernández-Aguilar, X., Antilles, N. & López-Soria, S., 2016. Toxoplasma gondii Infection in Seagull Chicks Is Related to the Consumption of Freshwater Food Resources. PloS one, 11(3), p.e0150249.
Understanding the spread of Toxoplasma gondii (T. gondii) in wild birds, particularly in those with opportunistic feeding behavior, is of interest for elucidating the epidemiological involvement of these birds in the maintenance and dissemination of the parasite. Overall, from 2009 to 2011, we collected sera from 525 seagull chicks (Yellow-legged gull (Larus michahellis) and Audouin’s gull (L. audouinii)) from 6 breeding colonies in Spain and tested them using the modified agglutination test (MAT) for the presence of antibodies against T. gondii. Chick age was estimated from bill length. Main food source of seagull chicks was evaluated using stable isotope analyses from growing scapular feathers. Overall T. gondii seroprevalence was 21.0% (IC95% 17.5–24.4). A generalized linear mixed-effects model indicated that year (2009) and food source (freshwater) were risk factors associated to the individual risk of infection by T. gondii, while age (days) was close to significance. Freshwater food origin was related to the highest seroprevalence levels, followed by marine origin, supporting freshwater and sewages as important routes of dispersion of T. gondii. Year differences could indicate fluctuating rates of exposure of seagull chicks to T. gondii. Age ranged from 4 to 30 days and seropositivity tended to increase with age (P = 0.07), supporting that seropositivity is related to T. gondii infection rather than to maternal transfer of antibodies, which in gulls is known to sharply decrease with chick age. This study is the first to report T. gondii antibodies in Yellow-legged and Audouin’s gulls, thereby extending the range of intermediate hosts for this parasite and underscoring the complexity of its epidemiology.

The yellow-legged gull, Larus michahellis, an occasional predator of Timon lepidus in the Atlantic Islands National Park (Galicia, NW Spain)

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Piorno, V., Fernández-Bouzas, J.A. & Velo-Antón, G. The yellow-legged gull, Larus michahellis, an occasional predator of Timon lepidus in the Atlantic Islands National Park (Galicia, NW Spain). Bol. Asoc. Herpetol. Esp. 27(1). (2016).

El lagarto ocelado (Timon lepidus) mantiene poblaciones de gran interés en varias islas, tanto por su estatus de conservación como por las particulares interacciones ecológicas que en ellas se desarrollan. En el caso del Parque Nacional de las Islas Atlánticas de Galicia, esta especie convive con una importante colonia de cría de gaviota patiamarilla (Larus michahellis). Desde el año 2009 hasta 2015 hemos detectado en este Parque Nacional siete casos de consumo de T. lepidus por L. michahellis. Se trata de una conducta nunca antes documentada y de reciente aparición, que podría estar relacionada con los efectos que el cierre de vertederos y la reducción de los descartes pesqueros están teniendo en esta especie de gaviota. El carácter ocasional de esta depredación no hace esperar efectos apreciables en estas poblaciones insulares de lagarto ocelado.

Las colonias de aves marinas de la costa Occidental de Galicia. Características, censo y evolución de sus poblaciones

Enlace mardeaves Larus fuscus,Larus michahellis,Phalacrocorax aristotelis,PUBLICACIÓN CIENTÍFICA,REPOSITORIO,Rissa tridactyla,Uria aalge ,,,

Bárcena, F. & Souza, J.A. Las colonias de aves marinas de la costa Occidental de Galicia. Características, censo y evolución de sus poblaciones. Ecología 1. (1987). ISSN 0214-0896

 

Begging response of gull chicks to the red spot on the parental bill

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Velando, A., Kim, S.-Y. & Noguera, J. C. Begging response of gull chicks to the red spot on the parental bill. Animal Behaviour 85, 1359–1366 (2013).

In some animals, offspring begging is elicited by parents through behavioural or morphological signals. The red spot on the lower mandible in adult gulls is one of the best-known examples of a signal triggering chick begging. We examined whether the begging response of chicks (pecking for food and the chatter call for drawing parental attention) was affected by the spot size within the natural range of variation on a dummy head. Using a cross-fostering experiment, we examined whether these responses covary with the size of the genetic or social parent’s spot. We found that the natural variation in size of this parental signal strongly influenced intensity of chick begging. Pecking increased when chicks were stimulated by a larger red spot. Additionally, pecking intensity increased in chicks reared by mothers with a large red spot, suggesting that this begging component is influenced by previous experience. In contrast, chick hatching order affected the number of chatter calls produced in relation to the size of the red spot on the dummy, suggesting the presence of different begging strategies according to brood hierarchy. The differential call response to a small/large red spot on the dummy was positively correlated with the original mothers’ red spot size and negatively with that of the original fathers. These results suggest a genetic correlation between biased chick response for a large spot and parental signal in contrasting patterns for mothers and fathers. Our results suggest that the parental red spot and offspring begging are traits subject to coevolution.

Influencia de la colonia de gaviota patiamarilla (Larus cachinnans Pallas) sobre el contenido de nutrientes (amonio y fósforo) en los suelos de los acantilados del Parque Natural de las Islas Cíes (SO de Galicia, NO de España).

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Otero Pérez, X. L. Influencia de la colonia de gaviota patiamarilla (Larus cachinnans Pallas) sobre el contenido de nutrientes (amonio y fósforo) en los suelos de los acantilados del Parque Natural de las Islas Cíes (SO de Galicia, NO de España). Thalassas 14, 57–62 (1998).

Los análisis realizados pusieron de manifiesto la presencia de concentraciones importantes de amonio (32.50 mg g-1) y de fósforo (16.58 mg g-1) en excrementos frescos de la gaviota patiamarilla (Larus cachinanns). Los resultados obtenidos para los suelos reflejaron un claro enriquecimiento en amonio cambiable y fósforo asimilable en los suelos de los acantilados donde se establece la colonia de esta especie. Las concentraciones de amonio presentaron diferencias entre las áreas de cría y la zona control (sin gaviotas), pero no entre las zonas de cría con densidades diferentes. Sin embargo, todas las áreas mostraron diferencias significativas entre ellas para el fósforo asimilable. Estos resultados parecen estar de acuerdo con el ciclo biogeoquímico de cada uno de estos dos nutrientes. El amonio puede ser oxidado pasando a la forma NO3- y este puede ser lavado fácilmente del suelo ya que apenas se encuentra absorbido por los coloides del suelo. Por el contrario los fosfatos pueden ser absobidos de manera específica por formas activas de Al y/o Fe o formando precipitados de Ca, Al, NH4+ y Fe3+ de baja solubilidad. Estos procesos favorecen su permanencia y acumulación en el suelo.

Effects of nesting yellow-legged gulls (Larus cachinnans Pallas) on the heavy metal content of soils in the Cies Islands (Galicia, North-west Spain)

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Otero Pérez, X. L. Effects of nesting yellow-legged gulls (Larus cachinnans Pallas) on the heavy metal content of soils in the Cies Islands (Galicia, North-west Spain). Marine Pollution Bulletin 36, 267–272 (1998).

Cd, Cr, Cu, Pb and Zn levels were determined in faeces of the yellow-legged gull Larus cachinnans in Galicia (NW Spain), and in soils from three breeding and one reference site. The levels of Cd, Cu, Zn and Pb in the soil were significantly higher at the site with highest gull density and with the longest history of use as a breeding site (Percha) than at the reference site. Zn levels were higher than levels of the other metals in all soil and faeces samples. Mean levels of metals in faeces were 305 mg kg-1 (Zn), 60 mg kg-1 (Cu), 40 mg kg-1 (Pb), 9.8 mg kg-1 (Cr) and 5.8 mg kg-1 (Cd).

Monitoring polycyclic aromatic hydrocarbon pollution in the marine environment after the Prestige oil spill by means of seabird blood analysis

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Pérez, C., Velando, A., Munilla, I., López-Alonso, M. & Oro, D. Monitoring Polycyclic Aromatic Hydrocarbon Pollution in the marine environment after the Prestige oil spill by means of seabird blood analysis. Environmental Science & Technology 42, 707–713 (2008).

In this studywetested the use of seabird blood as a bioindicator of polycyclic aromatic hydrocarbon (PAH) pollution in the marine environment. Blood cells of breeding yellow-legged gulls (Larus michahellis) were able to track spatial and temporal changes consistent with the massive oil pollution pulse that resulted from the Prestige oil spill. Thus, in 2004, blood samples from yellow-legged gulls breeding in colonies that were in the trajectory of the spill doubled in their total PAH concentrations when compared to samples from unoiled colonies. Furthermore, PAH levels in gulls from an oiled colony decreased by nearly a third in two consecutive breeding seasons (2004 and 2005). Experimental evidence was gathered by means of an oil ingestion field experiment. The total concentration of PAHs in the blood of gulls given oil supplements was 30% higher compared to controls. This strongly suggested that measures of PAHs in the blood of gulls are sensitive to the ingestion of small quantities of oil. Our study provides evidence that seabirds were exposed to residual Prestige oil 17 months after the spill commenced and gives support to the nondestructive use of seabirds as biomonitors of oil pollution in marine environments.

Parental food conditions affect sex-specific embryo mortality in the yellow-legged gull (Larus michahellis)

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Pérez, C., Velando, A. & Domínguez, J. Parental food conditions affect sex-specific embryo mortality in the yellow-legged gull (Larus michahellis). Journal of Ornithology 147, 513–519 (2006).

Different mortality of males and females during early post-hatching development in sexually size-dimorphic bird species is usually attributed to different nutritional requirements of the sexes, because mortality is mostly biassed toward the larger sex. We investigated whether sex-specific embryo mortality in the yellow-legged gull (Larus michahellis), a size-dimorphic seabird, depends on parental condition. To test this, we experimentally modified parental nutritional conditions by supplementary feeding of yellow legged gulls during egg formation, to evaluate sex-biassed environmental sensitivity of gull embryos. We found that eggs were larger in supplemented clutches, but egg size did not affect embryo survival. Survival of male gull embryos was more related to parental food conditions than was survival of female embryos. Survival of male embryos in supplemented clutches was greater than in unsupplemented clutches whereas survival of female embryos was similar in both groups. Because size at hatching was similar in both sexes our results suggest that male phenotype disadvantage is not exclusively linked to the energy demands of size-dimorphic development at the embryo stage.

Oil pollution increases plasma antioxidants but reduces coloration in a seabird

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Pérez, C., Lores, M. & Velando, A. Oil pollution increases plasma antioxidants but reduces coloration in a seabird. Oecologia 163, 875–884 (2010).

It has been suggested that condition-dependent signals may be a useful measure of environmental quality. In this study, we tested the hypothesis that oil pollution enhances oxidative stress and impairs expression of a carotenoid-based signal in a wild population of the yellowlegged gull (Larus michahellis). During the courtship period, a group of gulls were fed a supplementary diet containing heavy fuel oil from the Prestige oil spill and were compared with control gulls fed a similar supplementary diet without fuel oil. Blood levels of polycyclic aromatic hydrocarbons, the most toxic components of crude oils, were higher (30%) in the Prestige oil-fed gulls than in the control gulls. Plasma concentrations of vitamin E and carotenoids were also significantly higher in the Prestige oil-fed gulls (31 and 27%, respectively). Although, the plasma levels of lipid peroxidation markers were higher (13%) in gulls fed with Prestige oil than in the control gulls, these differences were not significant, possibly because of the small number of gulls analyzed. The red bill spot was significantly smaller (16%) in the oil-fed gulls than in the control individuals. This study provides the first experimental evidence that a carotenoid-based signal in a freeliving seabird is affected by exposure to oil pollution and is hence indicative of environmental quality. Since the yellow-legged gull belongs to a complex of species widely distributed throughout the northern hemisphere, the method described may constitute a useful tool for evaluating sublethal effects of oil spills in seabirds.