It looks like “skipping” : occasionally the computer isn’t listening to what you are recording for a millisecond while it’s doing something else , see … http://manual.audacityteam.org/o/man/faq_recording_troubleshooting.html#How_can_I_record_without_small_[b]skips[/b]_or_duplications.3F
Paul-L’s DeClick plugin will remove the clicks, but applying it can take several times the playback-time, depending on the settings used …