Use of time-lapse video cameras to determine causes of nest failure of Slavonian Grebes Podiceps auritus

Capsule Few clutches were predated, with Otter Lutra lutra the most frequent predator filmed. Aims To determine the rate of nest predation and identify predators of the Slavonian Grebe Podiceps auritus in Scotland. Methods Miniature 24-hour time-lapse video cameras were placed next to 23 Slavonian Grebe nests on five lakes to record nest failure events and to identify predators that depredated the contents of nests. For comparison, ten nests without cameras were also monitored and their outcomes recorded. Results The probabilities of clutch failure due to predation, and wave damage or water level rise were 19% and 30%, respectively. Otters took two clutches and an adult grebe plus chicks from nests. Other predators filmed at nests were Stoat Mustela erminea, Carrion Crow Corvus corone, Common Gull Larus canus and Coot Fulica atra. No difference in predation rates between nests with and without cameras was detected. Otters were recorded at eight of 13 lakes studied. An American Mink Mustelo vison was recorded at one lake. Conclusion The nest predation rate of Slavonian Grebe in Scotland was not high compared with other studies and is not of conservation concern.