An Etymological Dictionary of the German Language/Annotated/Strauß
Strauß (1.), masculine, ‘quarrel. conflict, fight,’ from the equivalent Middle High German strûȥ, masculine; to this Middle High German striuȥen, ‘to resist,’ Anglo-Saxon strûtian, ‘to quarrel,’ is allied.
Strauß (2.), masculine, ‘crest, tuft, nosegay,’ from the equivalent late Middle High German *strûȥ, masculine, which may be inferred from gestriuȥe and striuȥach, ‘cluster of bushes.’
Strauß (3.), masculine, ‘ostrich,’ from the equivalent Middle High German and Old High German strûȥ, masculine; it seems to be rather a corruption of late Latin strûthio, ‘ostrich,’ on which Anglo-Saxon strŷta is based (compare Italian struzzo, French autruche, whence English ostrich), than a permutation of pre-High German *strûto-. The word may have been borrowed contemporaneously with Pfau. On the other hand, a direct connection with Greek στρουθίον, or rather ἡ μεγάλη στροῦθος, ‘ostrich’ (στροῦθος, ‘sparrow’), is impossible. Moreover, it is remarkable that the Germans say Vogel Strauß, in the came way as the French autruche (Spanish av-estruz) from avistrutio, is liked with Latin avis.