To the best of my knowledge, there is no exact translation of the term “primillar” in English, so we need to use a descriptive term. “Primillares”, as the reference below describes, are nesting towers for lesser kestrels (Falco naumanni). “Primillar” derives from the Spanish term “cernícalo primilla”. This type of construction is typical for, as they call it, “Iberia”, i.e. Spain and Portugal.


www.lifefalkon.eu/en/news/nesting-tower-for-lesser-kestrel-...

Nesting tower for lesser kestrel of the Po Plain
Not only nest boxes: LIFE FALKON is fostering the recovery and the expansion of the northern population of lesser kestrel with the construction of small buildings entirely dedicated to the species! Tens of these towers had been edified in Iberia in the last twenty years (so-called ‘primillares’ from the Spanish name of the lesser kestrel, cernícalo primilla), and effectively supported the lesser kestrel recovery in the region. We are confident that this will also occur in the Po Plain thanks to LIFE FALKON towers! The external design of the LIFE FALKON towers has been harmonized to the local architecture, while fitting all the needs for the species. Internally, each tower will host 22 nest boxes, with the possibility to install remote-cameras for nesting surveillance or research purposes. To guarantee their long-lasting life, the towers will remain as property of local landowners or associations that has signed an agreement with LIFE FALKON and assure the maintenance of the building for at least 20 years.


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Note added at 25 mins (2023-02-21 19:17:56 GMT)
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See picture on page 3 of the following document:
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