Deletion of Battle of the Birds

Comment: Not actual rivalries recognized by any major |reliable sources. Just because teams play each other does not make them rivals. Besides, "battles of the birds" would merit just as much notability as an "Indian Rivalry" (Braves vs. Indians
Stance: delete
Cited policy: Wikipedia:Reliable sources (WP:RS)

Comment: Unsourced |Original research
Stance: delete
Cited policy: Wikipedia:No original research (WP:OR)

Comment: Orioles/Jays is one of the lesser AL East rivalries, while O's/Cardinals hasn't really happened; the Orioles pretty much downplay their history as the St. Louis Browns and that 'rivalry' is mainly notable as a nostalgic curiosity for older fans and history buffs, while Jays/Cardinals is about as routine a interleague series as you can get, interesting for a bit, but like a Marlins/Royals series, nobody but the teams and local fans really care about that one. Not really much here but 
Stance: delete
Cited policy: Wikipedia:No original research (WP:OR)