Question: which is the tallest flying bird in the world known to mate with single partner for life
[{'answer': 'sarus crane', 'provenance': [{'wikipedia_id': '42780708', 'title': 'Sarus crane', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 15, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]