http://revach.net/article.php?id=3479

Section: Shira   Category: AlephBais
Bais is for Bas HaYa'ana, The Ostrich
The Arizal brings from the Rishonim that an ostrich is unique in that it does not sit on its eggs nor does it place them high in a tree.  The ostrich buries its eggs in the sand and with its powerful vision it watches them from afar.  The eggs are able to develop from the heat of its gaze.

Rav Yaakov Emden says that because of the special power of the ostrich's eye, some Sefardi kehilos have a minhag to hang ostrich eggs in Shul.  The ostrich egg symbolizes the power in a persons eye wherever he glances.  Seeing these eggs inspire a person to have kavana and not to look around during davening. (Otzer Hayedios Rav Y. Michel Stern)