The main objective of this action is to test materials for the construction and effectiveness of a new design of next box for lesser kestrels that will provide better technical and ethological characteristics that will allow for an increase in breeding success for the species.

To produce new nest boxes a new mortar of cement with cork granules will be developed, which is a light, resistant, durable, breathable, thermal insulating and sustainable material. Cork is a material of great ecological value that contributes to the maintenance of important ecosystems in Extremadura, such as the cork oak woodlands. Its use as a binder in the production of cement mortar will permit improvements in the technical and ecological performance of the external nest boxes compared to the more usual sawdust-based mortar.

Task 1: Develop the new material from cork mortar for nest box production.

A selection of components for cement mortars with cork granules will be selected and both natural binders and cork granules will be characterised. A theoretical experimental method will be established to define different doses. This will include dosages of cork mortar with pigments in order to obtain different tones, allowing the better integration of nest boxes into their surroundings.

Once the different dosages have been defined, tests of compression, particulate density, granulometry, absorption, humidity and permeability to vapour will be determined under European quality norms, evaluating their thermic and durability properties.

These tests will allow for the selection of the dosages of cork mortar that offer the best properties for the manufacture of nest boxes for lesser kestrels.

Task 2: Study of design of artificial nest boxes.

Studies on design will be centred on meeting the biological needs of lesser kestrels and improve the quality of life, safety and productivity of the pairs, facilitating anti-predator systems, air-flow, prevention of chicks falling and allowing drainage of rain-water. In addition, account will be taken to ensure that these models are light and easy to install and manage, considering zones of difficult access where installation will sometimes be required.

An expert in the design and installation of artificial nest boxes will be available to design the nest boxes, provide advice through the action and coordinate the checks of the different models in the Lesser Kestrel Breeding Centre of DEMA and in an urban colony.

Task 3: Design and manufacture of nest box moulds.

  • The process for the design of the mould will be the following:
  • Design of the mould and of the drawings of the model in CAD.
  • Production of mother-moulds made by a model nest box from wood and polyester mould case.
  • Production of silicon mould for the later industrial production of next boxes.
  • Testing that the designed mould provides the required properties and qualities.

Task 4: Manufacture of artificial nest boxes.

For the industrial manufacture of the nest boxes adjustments will be made if necessary to the dosages obtained in the laboratory as the process is transferred to the factory. There will be two different productions of nest boxes:  

Test nest boxes made for validation for both technology and the environment during the 2017 breeding season. Through Task 5 their functioning will be checked and it will be seen if any modifications will be necessary. Once validated, the remaining nest boxes will be produced.

Nest boxes to be produced in two batches in 2018 and 2019. The nest boxes will be installed as part of the conservation actions of the project, as well as part of the requirements of mandatory Impact Reports in buildings included in urban SPAs. Finally, the nest boxes will be distributed within the scope of the project between the interested parties for installation in the Natura 2000 network in agreement with a memorandum of commitment on maintenance and follow-up signed by the General Directorate of the Environment.

Task 5. Evaluation of the performance of the artificial nest boxes.

For the technological evaluation of the nest boxes physical properties such as visual aspect, weight and resistance will be characterised. With respect to durability, the performance of these new nest boxes will be evaluated compared with traditional boxes with traditional mortars using sawdust binders through tests of cycles of freezing and defrosting and thermic shock. Checks will be made of temperature and humidity, recording data continually on the experimental models using sensors.

For the ethological evaluation of the species with these new experimental models, a careful monitoring will be undertaken through a system of video-recording in a colony noting data on occupation and/or exploratory behaviour. Through preference tests it will be determined which type of model are mainly selected for by the species.

This task will be developed in the installations of INTROMAC, DEMA and in an urban SPA.

Action 6 contributes to the conservation and the maintenance of the breeding sites of lesser kestrels which are in risk of loss and to reduce the mortality of chicks, both considered to be of medium importance in the European Action Plan for the Lesser Kestrel. The scarce availability of nesting cavities, competition for such sites with other species and predation on nesting sites are factors that impact negatively the lesser kestrel populations, for which it is important to address through the provision of artificial nest boxes.

In order to ensure the long-term viability of this investment, it is necessary that the nest boxes are easy to install, resistant, durable, easy to handle, fit-in with the surroundings, economic and easy to install in buildings as well as on pylons, wooden and cement poles. The new nest boxes will directly influence the breeding success of the species and therefore its recovery. In order to obtain nest boxes with these characteristics it is critically important to invest in the best materials and design.

Responsible for implementation: General Directorate of the Environment, Intromac, DEMA and Prefabricados Extremadura 2002.