Owl liver samples were sent from Kaunas Tadas Ivanauskas Museum of Zoology to the National Veterinary Research Institute in Puławy (Poland). Birds of prey are good indicators of environmental chemical contamination. European Raptor Biomonitoring Facility ERBFacility and LIFE APEX project perform biomonitoring of pollutants throughout Europe. Kaunas Tadas Ivanauskas Museum of Zoology joined the biomonitoring network in 2019.