The little bird in this theme is a background image on the .block-twitter a.followMe classes. To remove it, you can edit the style.css file that starts on line 565 to remove the part that says background: transparent url(images/twitter.png) no-repeat scroll center.
You may optionally also create an image more in tune with your image, and name is twitter.png and upload to the location shown above. This will use your image rather than the one that came with the theme.
Please note you must upload it to the wp-content/themes/mystique/images location.
Hope this helps.
Loving this theme!
Blogging Your Brand With WordPress
Twitter Feed Setting at Top
Unrelated the the background, but related to the Twitter settings for Twitter feed thingy at the top of the page…
I was able to “turn it on” by adding the Twitter Latest Tweets widget to the sidebar and giving it my Twitter id and saving.
If you didn’t want to keep the Twitter sidebar widget, once saved, just move it to the lower widget holder that allows you to store widgets and their settings for later use.