Bird-brained

We are lucky enough to have a pair of Mistle Thrushes nesting in a Corsican Pine tree in our garden. Their nest is about three feet from the top of the tree which is roughly half as high again as our house. The problem is that the tree is a favourite perch for our local crows and we all know that crows and birds nests don't mix very well. The thrushes knew that the crows used the tree as even when they were building the crows became a nuisance to them. The pair have been sitting now for about four days so I hope that they are defensive enough to be able to keep the crows away but surely they could have found a more secretive place to nest build.