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    Habitat-related Egg Size Differences and Hatching Success in the Spur-Winged Lapwing Vanellus spinosus (L., 1758) (Charadriiformes: Charadriidae)
    (Inst Zoology, Bas, 2023) Ozkan, Leyla
    Egg size in birds is a factor that affects their reproductive success, especially in the size and survival rates of the chicks. Until they learn to find food within a few days after hatching, precocial-type chicks need to use their own biological reserves to supply the energy they expend in walking, running, hiding from predators, etc. The spur-winged lapwing Vanellus spinosus (L., 1758) is a common lapwing species having precocial-type offspring. The species is seen as a summer visitor in Tfirkiye and Bogazkent is one of its important breeding areas in the country. In the present study, the characteristics of the eggs laid in three habitats (agricultural lands, barren lands and meadows) within this area were compared. To this purpose, the eggs were weighed and their width and length were measured. In addition, the volume and sphericity index of the eggs were calculated. We found significant differences in egg measurements between the habitats with eggs laid in meadows being larger, heavier and with greater egg volume than in the other two habitats. However, the hatching rates in the meadows were the lowest (43.8 %) in comparison with the agricultural lands (67.7 %) and barren lands (73.3 %), possible due to potentially higher predation pressure in meadows.
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    Persistent organochlorine pollutant residues in water, sediment, and fish from Efteni Lake, North-West Turkiye
    (Brill, 2023) Ozkan, Leyla
    The Efteni Lake, Wildlife Development Area is under anthropogenic pressure regarding agriculture and water management. This study aimed to determine and evaluate the persistence of an organochlorine pollutant (POP) and its bio-accumulation and bio-magnification from the water to fish in the lake. Therefore, water, sediment, and fish (Tinca tinca) specimens were collected from different points in the lake. The study showed that dichlorodiphenyltrichloroethane (DDT) compounds were the highest among the organochlorine pesticide (OCP) groups and were found in 100% of all specimens. However, the frequency rates and the concentrations recorded for 4,4-DDT (a DDT metabolite) were higher than for DDT compounds in all three specimen types. The mean total polychlorinated biphenyl (PCB) concentrations were 0.17 & PLUSMN; 0.03 ng/g, 0.31 & PLUSMN; 0.03 ng/g, and 0.61 & PLUSMN; 0.03 ng/g in the water, sediment, and fish specimens, respectively. In conclusion, the concentration of OCPs in the water significantly was lower than in the sediment and fish. The top three PCB congeners, as per their mean levels were PCB 138, 151, and 153. Reducing human pressure on Efteni Lake is crucial because POP residues in the lake are likely to pose a danger to aquatic organisms, other wildlife, and to human health.