Paula Schatte and co-authors share insight from their recent study examining the relative importance of food availability and conspecific vocalisations for breeding habitat selection during both the prospecting and breeding periods of a regionally endangered woodpecker, the Eurasian Wryneck (Jynx torquilla).
What is the problem?
The Wryneck suffered a long-term decline in western and northern Europe until the beginning of the 21st century, mainly due to agricultural intensification. It is still quite widespread in Switzerland today, but in many parts of the country it occurs at low densities or even sporadically. The availability of food, almost exclusively eggs, larvae, pupae and adults of various ant species, and nest cavities are known limiting factors for the Wryneck. Conservation efforts have therefore focused on the provision of nest boxes and habitat improvement by providing areas of low vegetation height or sparse ground cover to achieve increased densities of accessible ant nests. While the population trend in Europe is mixed, in Switzerland it has been positive in recent years, partly due to these efforts. However, Wryneck settlement in low-density areas is rare, which may be due to the lack of social cues in high-quality habitats. If this is the case, playback of conspecific vocalisations could be a promising conservation tool to promote settlements in high-quality breeding sites.
What did we do?
We did a playback experiment in previously unoccupied plots of high and low food availability. The main aims of this experiment were to test the playback of Wryneck vocalisations as a conservation tool and to disentangle the relative importance of food availability and conspecific vocalisations for habitat selection during prospecting and settlement of Wrynecks.
What did we find?
We found that food availability varied considerably among agricultural field types, with the highest values in vineyards and the lowest values in intensively managed grassland. The results supported that high food availability increased both Wryneck prospecting and settlement probability of potential breeding sites. Playback treatments increased Wryneck prospecting probability but not Wryneck settlement probability. This was only the case when food availability was poor, but not when food availability was favourable. Finally, and most importantly for conservation, the playback treatment had no effect on the breeding success of breeding Wrynecks.
Why is it important?
We show that Wrynecks can be attracted to suitable breeding sites by playback but will not settle if food availability is poor. High food availability is therefore a key factor in Wryneck breeding habitat selection and hence Wryneck conservation. Our results suggest that although Wrynecks use conspecific vocalisations as information for prospecting, they rely mainly on habitat characteristics for their final settlement decision. Consequently, habitat quality, and in particular food availability, is more important and a critical requirement for successful Wryneck conservation management.
Our results allow for three recommendations to improve Wryneck conservation:
1. Nest box provision: To maximise conservation efforts, we recommend that Wryneck nest boxes should only be installed on sites with high food availability. In our study area, this is particularly true for sites with high proportions of vineyards and extensively managed meadows. Nest boxes are mainly installed and maintained by nature conservation organisations on a voluntary basis. Increasing the efficiency of their efforts will certainly help to increase the motivation and reinforce the commitment of volunteers.
2. Habitat management: To improve habitat quality in terms of food availability, we recommend ant-friendly agricultural management practices. Valuable options include reducing the intensity of land use and nutrient-reducing field treatments, such as alternate vegetating of vineyard rows, grazing-rotation or mowing regimes, resulting in a mosaic of different field structures in pastures and meadows.
3. Playback of conspecific vocalisations: Playback may serve as a cost-effective tool to attract Wrynecks to sites of conservation efforts without causing negative impacts. We recommend that it could be used selectively as a conservation. Playback is therefore included in the Swiss Wryneck Conservation Strategy, which is part of the “Species Conservation for Swiss Birds” programme coordinated by the Swiss Ornithological Institute, BirdLife Switzerland and the Federal Office for the Environment. We are confident that playback does not create an ecological trap. Nevertheless, playback must always be used with caution and accompanied by an impact assessment.
Read the full article “Playback attracts prospecting individuals, but habitat quality is key for settlement in the Wryneck Jynx torquilla“ in Journal of Ecological Solutions and Evidence
