Question: what nfl team is called the dirty birds
[{'answer': 'Atlanta Falcons', 'provenance': [{'wikipedia_id': '3055481', 'title': 'List of NFL nicknames', 'start_paragraph_id': 21, 'start_character': 34, 'end_paragraph_id': 21, 'end_character': 49, 'bleu_score': 1.0, 'section': 'Section::::Teams and units.\n'}]}, {'provenance': [{'wikipedia_id': '3055481', 'title': 'List of NFL nicknames', 'start_paragraph_id': 21, 'start_character': 0, 'end_paragraph_id': 21, 'end_character': 210, 'bleu_score': 0.943604326170661, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6649668877067676807}, 'section': 'Section::::Teams and units.\n'}]}]