1. How many ground nesting birds live in the U.K.? What proportion are endangered and live in deciduous woodlands?
Potential drawbacks
One of the potential limitations of this experiment is the use of artificial nests over natural ones, which attract different predators. Previous experiments have shown artificial nests can overestimate predation rates, by attracting different predators \cite{WEIDINGER_2008}. In addition, artificial nests do not mimic the seasonal variation in predation rates observed in natural nest experiments \cite{Zanette_2002}. The cryptic nature of artificial nests may provide a source of bias during fixed nest experiments, especially if there are associated sensory cues. While olfactory cues from the plasticine eggs in this experiment was controlled for, the artificial nests were made from non-native conifer leaves, which may have provided cues to predators. This experiment was also short lived, having only been run for 2 weeks post spring, which only provides a brief insight into the nature of the edge of this forest. Future studies should aim to control for seasonality by performing longer term experiments, especially when orientation plays a factor in the abiotic conditions of the edge.
Acknowledgements
I would like to thank Cristina Banks-Leite of Imperial College London for help and advice regarding the pilot study, statistical analysis and invaluable guidance. I would also like to thank the technical staff at Silwood Park for their assistance using the GPS unit for spatial analysis. Many thanks to the Biology Undergraduate department, without whom this project could not be possible.