Dreck and Schmutz mean basically the same thing in German: dirt. A Spatz is a sparrow and a Fink a finch. Hitched to a word meaning "dirt", they refer to people who get themselves dirty easily and may not be too eager to clean up after themselves. Dreckspatz, in particular, is often applied to children who actually enjoy playing in the mud and getting it all over themselves.
Note on pronunciation: The "u" in Schmutz is a short "oo" as in "foot" and the "z" in Spatz and Schmutz a very sharp, voiceless "s".
[Source: Wild Things in the German Language: Kindle version | iBook version]
5 hours ago