Use xargs to copy files
You want to perform a copy, move or some other operation where the argument you pass in using xargs isn't at the last argument for the following command. Do as follows:
ls -tr1 | tail -5 | xargs -i cp '{}' dest/folder/
You might also need to add the option -n1 if the output from the ls command (or whatever else it may be) is larger than your shell's buffer. i.e.
... xargs -n1 -i cp '{}' dest/folder