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Delaware Bay, US is the only documented location where influenza A virus (IAV) is consistently detected in a shorebird species, the Ruddy Turnstone (RUTU; Arenaria interpres morinella). Although IAV in shorebirds has been well studied at this site for decades, the importance of other species in the avian community as potential sources for the IAVs that infect RUTUs each spring remains unclear. We determined the susceptibility of Mallards (Anas platyrhynchos) and Laughing Gulls (Leucophaeus atricilla), to IAVs isolated from RUTUs in order to gain insight into the potential host range of these viruses. Captive-reared gulls were challenged with RUTU-origin H6N1, H10N7, H11N9, H12N4, and H13N6 IAV, as well as Mallard-origin H6N1 and H11N9. We challenged captive-reared Mallards with the same viruses, except for H13N6. At a biologically plausible challenge dose (104 50% embryo infective doses/0.1 mL), one of five gulls challenged with both H6N1 IAVs shed virus. The remaining gulls were resistant to infection with all viruses. In contrast, all Mallards were infected and shed virus. The H12N4 Mallard challenge group was an exception with no birds infected. These results indicated that Mallards are permissive to infection with viruses originating from a shorebird host and that interspecies transmission could occur. In contrast, host adaptation of IAVs to RUTUs may compromise their ability to be transmitted back to gulls. [ABSTRACT FROM AUTHOR]

Scoping studies were designed to determine if double-crested cormorants ( Phalacocorax auritus ), laughing gulls ( Leucophaues atricilla ), homing pigeons ( Columba livia ) and western sandpipers ( Calidris mauri ) that were gavaged with a mixture of artificially weathered MC252 oil and food for either a single day or 4–5 consecutive days showed signs of oil toxicity. Where volume allowed, samples were collected for hematology, plasma protein electrophoresis, clinical chemistry and electrolytes, oxidative stress and organ weigh changes. Double-crested cormorants, laughing gulls and western sandpipers all excreted oil within 30 min of dose, while pigeons regurgitated within less than one hour of dosing. There were species differences in the effectiveness of the dosing technique, with double-crested cormorants having the greatest number of responsive endpoints at the completion of the trial. Statistically significant changes in packed cell volume, white cell counts, alkaline phosphatase, alanine aminotransferase, creatine phosphokinase, gamma glutamyl transferase, uric acid, chloride, sodium, potassium, calcium, total glutathione, glutathione disulfide, reduced glutathione, spleen and liver weights were measured in double-crested cormorants. Homing pigeons had statistically significant changes in creatine phosphokinase, total glutathione, glutathione disulfide, reduced glutathione and Trolox equivalents. Laughing gulls exhibited statistically significant decreases in spleen and kidney weight, and no changes were observed in any measurement endpoints tested in western sandpipers. [ABSTRACT FROM AUTHOR]

During the Deepwater Horizon Natural Resource Damage Assessment, gross morphologic cardiac abnormalities, including softer, more distensible musculature, were noted upon gross necropsy in hearts from laughing gulls and double-crested cormorants exposed to weathered MC252 crude oil. A species specific, echocardiographic technique was developed for antemortem evaluation of function that was used to evaluate and better characterize cardiac dysfunction. Control (n=12) and treated (n=13) cormorant groups of similar sex-ratio and ages were dermally treated with approximately 13 ml of water or weathered MC252 crude oil, respectively, every 3 days for 6 dosages. This resulted in a low to moderate external exposure. Upon visualization and clinical assessment of the hearts of all test subjects, comprehensive diagnostic cardiographic measurements were taken twice, prior to oil application and after a 21 day dermal oil exposure. Oil-treated birds showed a decrease in cardiac systolic function, as characterized by an increased left ventricular internal dimension-systole and left ventricular stroke volume as well as concurrent decreased left ventricular ejection fraction and left ventricular fractional shortening when compared to both control birds’ and the treated birds’ time zero values. These changes are indicative of a possible dilative cardiomyopathy induced by oil exposure, although further elucidation of possible collagen damage is recommended. Arrhythmias including tachycardia in two treated birds and bradycardia in all treated birds were documented, indicating further clinically significant abnormalities induced by MC252 oil that warrant further investigation. A statistically significant increase in free calcium concentration, important to muscular and neurologic function in treated birds was also noted. This study documents that weathered MC252 oil caused clinically significant cardiac dysfunction that could result in mortality and decrease recruitment. [ABSTRACT FROM AUTHOR]

The explosion of the Deepwater Horizon oil rig released, millions of gallons of oil into the environment, subsequently exposing wildlife, including numerous bird species. To determine the effects of MC252 oil to species relevant to the Gulf of Mexico, studies were done examining multiple exposure scenarios and doses. In this study, laughing gulls ( Leucophaeus atricilla , LAGU) were offered fish injected with MC252 oil at target doses of 5 or 10 mL/kg bw per day. Dosing continued for 27 days. Of the adult, mixed-sex LAGUs used in the present study, ten of 20 oil exposed LAGUs survived to the end of the study; a total of 10 of the oil exposed LAGUs died or were euthanized within 20 days of initiation of the study. Endpoints associated with oxidative stress, hepatic total glutathione (tGSH), oxidized glutathione (GSSG) and reduced glutathione (rGSH) significantly increased as mean dose of oil increased, while the rGSH:GSSG ratio showed a non-significant negative trend with oil dose. A significant increase in 3-methyl histidine was found in oil exposed birds when compared to controls indicative of muscle wastage and may have been associated with the gross observation of diminished structural integrity in cardiac tissue. Consistent with previous oil dosing studies in birds, significant changes in liver, spleen, and kidney weight when normalized to body weight were observed. These studies indicate that mortality in response to oil dosing is relatively common and the mortality exhibited by the gulls is consistent with previous studies examining oil toxicity. Whether survival effects in the gull study were associated with weight loss, physiologic effects of oil toxicity, or a behavioral response that led the birds to reject the dosed fish is unknown. [ABSTRACT FROM AUTHOR]

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The article discusses a survey of the seabird colonies in the small islands of Bahía Santa Marí-La Reforma, Sinaloa, Mexico during the breeding seasons from 2010 to 2012. The survey showed that Bahia Santa María had the largest breeding colonies for Laughing Gull, Royal Tern and Black Skimmer while colonies on El Rancho increased due to increased habitat availability. For reasons unknown, decrease was noted on Brown Pelican population breeding in mangrove islands.

The article discusses a study that was conducted in South Carolina between 2006 and 2007 concerning seabird attendance at shrimp trawlers in nearshore waters. The study procedure included seabird surveys that were conducted at several fishing vessels including Cape Romain, Miss Georgia, and Winds of Fortune. Analyses were focused on several types of birds including Sandwich terns, Laughing Gulls, and Brown Pelicans. The relationship between the abundance of species and variables was evaluated using a model selection approach and generalized linear models.

The article explains the differences between the bird species, Laughing and Franklin's Gulls. Laughing Gulls do not breed in the state of Connecticut, but in late summer and early fall birds from nearby breeding colonies. Franklin Gulls, meanwhile, are an abundant breeding gull of the midwestern prairies. In flight, Laughing Gulls have black primaries that blend right into the gray wings and small white primary mirrors while Franklin's have black-wingtips that are isolated from the gray wings by a white band and have large white mirrors.