Important factors for predation of northern lapwing Vanellus vanellus nests in a central European lowland pasture system
Khil Leander, University of Vienna (AT)
In the last decades, lapwing populations decreased dramatically all across Europe due to shifts in land use and agricultural intensification. Knowledge of the threats to a species is essential to design appropriate conservation measures. Nest loss and insufficient productivity in the remaining habitats have been a main cause for declines. In this study, the causes for and the factors determining nest loss in the lapwing in the Neusiedler See - Seewinkel National Park were investigated. Clutches were recorded and monitored until they hatched or failed and the fate of each nest was assessed. Additionally, data on vegetation and ground humidity at the nest site were gathered to test for effects of habitat variables on hatching success. Nest temperatures were recorded through temperature data loggers to record if diurnal or nocturnal predators were involved in nest predations. Artificial nests were deployed at the study site and monitored until they were predated. The results were used to demonstrate the strong anti-predator defense of lapwing colonies. Trail cameras were used to monitor artificial nests to reveal potential predators. 59% of all nests and 97.5% of failed lapwing nests were predated. The average probability for a nest to survive until hatching was 20.3%. Nest survival probabilities differed significantly between different colony sizes (> 5 nests: 55%, 2-5 nests: 14.8%, solitary nests: 3.5%). Colony size was the only statistically valid predictor for nest loss probability. Vegetation cover, sward height and ground humidity at the nest site, as well as rainfall did not prove being significantly related to nest loss. Predation risk of artificial nests was negatively correlated with the distance to the next four lapwing nests. According to nest temperature data, 14 of 18 monitored nests were predated at night. Thus, nocturnal/mammalian predators are very likely to be the main predators of lapwing nests. Trail cameras recorded 12 predations of artificial nests, all by corvids. Hence, artificial nest exposure experiments can be unreliable when aiming to identify important predators. Our results emphasize the importance of sufficiently large areas of suitable habitat, where colonies can develop, which have a higher hatching success than solitary nests on small habitat patches.