Haematology and blood chemistry of healthy and clinically abnormal great black‐backed gulls (<i>Larus Marinus</i>) and herring gulls (<i>Larus Argentatus</i>)

Normal haematological values and cholesterol values (total, HDL-cholesterol, LDL-cholesterol) were determined in free-living Herring and Great Black-backed Gulls, taking into account species, age and sex. These figures were then used as a basis of comparison with findings on birds with apparent clinical abnormalities (the birds were either oiled, emaciated, extensively infested with endoparasites, had external injuries or organic abnormalities). Species-specific differences were found only in cholesterol content; sex-specific differences were not found. There were statistical differences between older birds and nestlings in RBC, PCV, Hb, MCV, MCHC and MCH. An age-related increase between 3- and 6-month-old birds and adults concerning total cholesterol and HDL-cholesterol was evident. The haematological values of healthy gulls showed statistical significant differences in RBC, Hb, MCV, MCHC, MCH, total cholesterol, HDL-cholesterol compared to the values obtained from sick gulls.