def add_precision_recall_f1(df):
    p = df['Old Bird Calls'] / df['Old Bird Clips']
    r = df['Old Bird Calls'] / df['Ground Truth Calls']
    df['Precision'] = to_percent(p)
    df['Recall'] = to_percent(r)
    df['F1'] = to_percent(2 * p * r / (p + r))