Common Swift exploring the nestbox at my house

Short video with sounds of common swifts.

[@faskr1927]

What is the best time to use swift call to attract them to the nest can I use it at night?

[@DerkvanL]

The nesting starts somewhere end of june start of july (Netherlands). We see this turning earlier because of draught in Southern Europe, because they migrate further north earlier now. I don't know if the call will get them to nest. It's mostly starting when the number of swifts grow bigger.