I've noticed lots of symbols of a sparrow or swallow throughout the show. Alisha has one on a necklace: http://40.media.tumblr.com/tumblr_lhx0zhZTcr1qzfdvco1_500.jpg
Jamie, Nathan's brother has one on his neck: http://41.media.tumblr.com/1d59ee09242c2ee4fdc010bb80810598/tumblr_mxurmuWnSX1sfcq8ho4_1280.png
and Rudy has one on his hand:http://26.media.tumblr.com/tumblr_lu0o18Ojqr1qedzwno1_r1_500.jpg
Those are the ones I can think of at the moment but there is probably more. Could be just coincidental but I was wondering if anyone knows of any symbolism that could be related?