Yellow-legged Gull Larus Cachinnans Research Articles

The Effects of Culling on Attacks by Yellow-Legged Gulls (Larus cachinnans) upon Three Species of Herons

The Effects of Culling on Attacks by Yellow-Legged Gulls (Larus cachinnans) upon Three Species of Herons

Dioxins, furans and AHH-active PCB congeners in eggs of two gull species from the Western Mediterranean

Polychlorinated biphenyls, dibenzodioxins and dibenzofurans were analysed in eggs of a protected gull species, the Audouin's Gull ( Larus audouinii) and compared to those of the Yellow-legged Gull ( Larus cachinnans), both breeding in the Western Mediterranean (Ebro Delta and Medes Islands, respectively). Differences in concentrations as well as in congener profiles reflected differences in both habitat and diet of the two species. Levels of AHH-active PCB congeners were lower in Yellow-legged Gull (0.4–1.6.μg/g d.w) than in Audouin's Gull eggs (1.2–33.9 μg/g d.w.). These concentrations, expressed in international toxic equivalence factors (i-TEQ/g d.w.), were on average 24 times higher in the Audouin's gull. I-TEQ levels due to dioxins were also higher in this species by a factor of ca. 7. I-TEQ levels related to PCBs resulted 90–230 times higher than those of dioxins and furans. Thus, AHH-inducing PCBs might represent even higher toxicological hazards than dioxins and furans to some populations of seabirds. The necessity of assessing the impact of these compounds in rare and protected species is pointed out.

Factors Affecting Kleptoparasitism and Predation Rates upon a Colony of Audouin's Gull (Larus audouinii) by Yellow-Legged Gulls (Larus cachinnans) in Spain

Factors Affecting Kleptoparasitism and Predation Rates upon a Colony of Audouin's Gull (Larus audouinii) by Yellow-Legged Gulls (Larus cachinnans) in Spain

Long term monitoring of pollutants in eggs of Yellow-legged Herring Gull from Capraia island (Tuscan Archipelago)

Chlorinated hydrocarbons (hexachlorobenzene, lindane, pp'DDE, polychlorinated biphenyls) and trace elements (Hg, Se, Cd, Pb) were determined in eggs of Yellow-legged Herring Gull (Larus cachinnans) collected in an island of the Tyrrhenian Sea during the period 1981-1986. PCBs levels vary on the average between 30.4μg g(-1) d.w. in 1981 to 56.1 μg g(-1) d.w. in 1983. The capillary chromatograms revealed the presence of about 30 somers of PCBs without significant variations in the eggs of the same year; more than 50% of the residues is made up only three isomers: the 22'44'55', the 22'344'5' and the 22'344'55'. Average DDE residues were 7-8 times lower than those of PCBs and declined during the period (from 9.2 μg g(-1) d.w. in 1981 to 4.5 μg g(-1) d.w. in 1986). Cadmium and lead are present in low concentrations. The average levels of mercury and selenium are around 2-2.5 μg g(-1) d.w., and a cumulative correlation, on a molar basis, exists between these two elements.