{'fraction_non_alphanumeric': 0.037829766052762566, 'fraction_numerical': 0.03334992533598805, 'mean_word_length': 4.630252100840337, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 1, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Song Type for Intrasexual Interaction in the Bush Warbler

In many species of passerines, males sing more than one song type (Kroodsma and Baylis 1982). Recent studies have shown that the use of different song types can vary depending on the sex of the receiver (Kroodsma 1981, Catchpole 1983, Groschupf 1985, Smith and Smith 1992, Wiley et al. 1994, Luschi and Seppia 1996), the level of intrasexual aggression (Lein 1972, 1978; Trainer 1987), and whether the song is used for long-range or short-range communication (Lein 1978, Catchpole and Leisler 1989, Titus 1998). Bush Warblers (Cettia diphone) are small passerines that breed from April to October throughout most of Korea. Their songs consist of an introductory ‘‘whistle’’ portion and an ending ‘‘syllable’’ portion (see Fig. 1). The whistle portion is composed of 1 to 15 notes, and the syllable portion has 2 to 6 syllables. Bush Warblers give two distinctive song types that are easily recognized in the field. In the first half of the song, one type has an intensive and continuous whistle, whereas the other type has a weak and discontinuous whistle. Yoon et al. (1995) analyzed singing rate, syllable composition, and physical characteristics of the two song types from three local populations of Bush Warblers. They found that the number of notes in the whistle portion was the most distinctive feature to define the song types. The alpha song has only one or two notes in the whistle portion and seems to have one long, continuous introductory note (Fig. 1). In contrast, the beta song has more than two notes in the whistle portion (Fig. 1), which sounds like a stuttered whistle. Compared with beta songs, alpha songs have fewer notes and a higher dominant frequency in the whistle portion, a higher maximum frequency in the syllable portion, and are of longer overall duration (Table 1). Alpha songs also have more syllables in the syllable portion than do beta songs, and the duration of the syllable portion is longer (Table 1, Fig. 1).