This small falcon has recently arrived from its winter range. The crows do not like this situation at all, and it has made them very nervous. They fly close to the Merlin calling from her high perch in a spruce tree and loudly voice their disapproval of the falcon's encroachment on their territory. It doesn't seem to have any affect on the Merlin. The Merlin, rather than building her own nest, will often take over an abandoned corvid nest, and later pose a danger to young birds. So, of course the crows do not want the Merlin anywhere near them and will try to drive the bird away.