The behaviour of a pair of Spectacled Guillemots Cepphus carbo in a nest was recorded by a small 4K camera during four breeding seasons. Parents started to visit the nest in mid-April to mid-May, and laid eggs in mid-May, 2 – 9 days after copulation in the nest. Long (> 3 days) absence from the nest before egg-laying, i.e. exodus, was not observed. Clutch size was two in 2019 and 2020 and one in 2021 and 2022. Chicks were hatched after an incubation period of 28 – 31 days; two chicks fledged in 2019 and one in 2020 and 2022 at 35 – 46 day- age, but not in 2021 because two other birds took over the nest in mid-Jun. Males visited the nest more often than females during the pre-laying period but the time in the nest, the time for incubation and the frequency of feeds were similar. Parents brought mainly sand lance Ammodytes spp. in 2019 (85% in number) and 2020 (95%), but its proportion decreased in 2021 (58%), and they brought demersal fish only in 2022. No apparent sex differences in the prey species provided were observed. High-quality images collected by a small camera set in the nest help studies of behaviour of the burrow/crevice nesting seabirds during the pre-laying period.
