The impact of researcher disturbance on nest predation rates: a meta-analysis
Article first published online: 7 NOV 2011
© 2011 The Authors. Ibis © 2011 British Ornithologists’ Union
Volume 154, Issue 1, pages 5–14, January 2012
How to Cite
IBÁÑEZ-ÁLAMO, J. D., SANLLORENTE, O. and SOLER, M. (2012), The impact of researcher disturbance on nest predation rates: a meta-analysis. Ibis, 154: 5–14. doi: 10.1111/j.1474-919X.2011.01186.x
- Issue published online: 15 DEC 2011
- Article first published online: 7 NOV 2011
- Received 23 March 2011; revision accepted 6 October 2011. Associate Editor: Jim Reynolds.
- breeding success;
- human perturbation;
- investigator activities;
- observer effect
The effects of visits to nests by researchers interested in quantifying avian nesting success have received considerable attention, as researchers have long been concerned about the possible negative effects of their own activities on the resulting estimates. There is a widely held view that investigator disturbance has an overall negative effect on breeding success by increasing nest predation rates in the nests studied. However, to date no one has statistically assessed the empirical evidence for such a relationship. We undertook a meta-analysis of published results to assess whether researcher activities increase nest predation in birds. We also assessed the variability in this effect in relation to the traits of the study species and the methodology used. These analyses used data from 18 experimental studies involving 25 species from six avian orders. Our results suggest that, contrary to the traditional view, researcher activities do not generally affect the incidence of nest predation. Moreover, this relationship appears inconsistent among avian orders and, surprisingly, nest survival of passerines increased weakly with researcher activities. We also found significant positive effects of researcher activity on nest survival for species breeding on coastal areas and for species nesting on the ground. The possible explanation for these differences among orders and guilds could be due to different nest predator communities. This new perspective on the effect of investigators could have important implications for bird management and conservation, as well as for other fields of study such as ecology and evolution, in which nest survival rates measured in the field are widely used to test and support a range of hypotheses.