Placement, survival and predator identity of Eurasian curlew Numenius arquata nests on lowland grass-heath

Natalia B. Zielonka, Robert W. Hawkes, Helen Jones, Robert J. Burnside, Paul M. Dolman

Capsule

Within the UKs largest lowland Eurasian Curlew Numenius arquata population, curlew preferentially nested on physically-disturbed (treated) than undisturbed (control) grassland, and low nest survival rates were primarily attributable to Red Fox Vulpes vulpes.

Aims

To inform conservation interventions for curlew within semi-natural lowland dry-grassland landscapes.

Methods

Across a 3,700 ha lowland dry-grassland landscape, over two years, effects of ground-disturbance management on Curlew nest placement (n=41) were examined using GLMs controlling for vegetation strata; effects of site and management on nest survival (n=44) were examined controlling for lay date and year. Nest predator identity was investigated using temperature sensors (n=28) and nest cameras (n=10).

Results

Curlews were five times more likely to nest on physically-disturbed than undisturbed grassland. Nest survival (0.24 ± 0.07, SE) was not influenced by year or ground-disturbance but declined with lay date and differed markedly between the two sites, consistent with predator control. Predation accounted for 33/36 of failed nests and was predominantly at night (17/23 cases where timing was known, p<0.001), consistent="" with="" mammalian="" predators.="" cameras="" indicated="" foxes="" to="" be="" the="" main="" predator="" (4/5="" cases).="" overall="" breeding="" productivity="" was="" 0.16="" ±="" 0.01="" (se)="" chicks="" per="" nesting="" attempt.="">

Conclusion

Curlew suffered from unsustainably high rates of nest predation primarily attributable to Foxes. A combination of perimeter fencing and lethal predator control appeared to improve nest success at one site. Ground-disturbance treatment could encourage nesting attempts in areas managed to minimise predator density.