You only need to display licenses to the user, which require this explicitly. LGPL and BSD should not do that. But you are often required to do so, if you modify existing libraries. So unfortunately you have to dig through the licenses for the ones not using a standard type like Apache, GPL/LGPL or BSD.
If you really are unsure and want to give appropriate credit, I would implement kind of an about dialog, which shows the library names and the type of license. Optionally you could add a link to the license file to make it more convenient for the user.