why does is_copy_constructible return true for unique_ptr

I would have expected this static assertion to fire:

#include <type_traits>
#include <memory>

int main() {
  static_assert(std::is_copy_constructible<std::unique_ptr<int>>::value, "UPtr has copy constructor?");
}

But it does not.

Compiled using vc12:

Microsoft (R) C/C++ Optimizing Compiler Version 18.00.31101 for x64