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The perception, structure, and function of female song in the black-capped chickadee (Poecile atricapillus)
- Author / Creator
- Montenegro, Carolina
The black-capped chickadee (Poecile atricapillus) is a non-migratory songbird found throughout North America who communicates primarily through its numerous vocalizations, each with various functions. The vocalizations of the black-capped chickadee can be divided into calls and songs. Calls serve functions crucial for survival (e.g., altering to predator presents; keeping track of flockmates) while songs are produced specifically for mate attraction and territorial defense. The black-capped chickadee has a single song called the fee-bee song, a short (~1s) two-note vocalization. While songbird songs are traditionally thought to be produced primarily by males, there is an increasing number of studies of female song in songbirds. The studies contained in this dissertation further support the argument that females produce song and that female song serves a function, through investigating female song in the black-capped chickadee. A recent study has shown that female black-capped chickadees do sing, and that female song is distinct from male song and suggests that female-produced song may be used for mate recognition (Hahn et al., 2013). In Chapter 2, I conducted operant conditioning go/no-go discrimination tasks to test black-capped chickadees’ perception of female song. The results indicated that female and male chickadees can learn to discriminate among individual females via their songs and generalize responding to novel songs from the same individual females after training. In addition, both sexes can generalize their responding using only the bee-note portion of the female song, meaning that when given only a portion of the fee-bee song, subjects could still identity individual females. Next, I conducted discriminant function analyses and used artificial neural networks to examine which acoustic measures are important for classifying individual female songs (Chapter 3). Analyses showed that both notes of the fee-bee song likely play a role in classification and thus discrimination, and that song can also be classified by the season it was produced in (i.e., spring vs. fall). These findings are in line with the differences that are evident in male chickadee song by season and in that males can be identified as individuals by their fee-bee song. In Chapter 4, I used an operant conditioned go/no-go discrimination task to investigate the impact of anthropogenic noise on the ability of female and male chickadees to discriminate among individual female chickadee songs. Findings suggested that even low-level noise (40dB) performance decreased compared to performance in silence, and high-level noise was increasingly detrimental to discrimination. We learned that perception of fee-bee songs does change in the presence of anthropogenic noise such that birds take significantly longer to learn to discriminate between females, but birds were able to generalize responding after learning the discrimination. Overall, the results of the above studies reveal that the female fee-bee song contains cues that allows both sexes of chickadees to identify individual females. While chickadees can discriminate between females when listening to the bee-note portion of a female’s song, bioacoustic analysis identified that both notes (i.e., fee and bee) are important in classifying female song. In addition, differences in acoustic features differ by season, further
suggesting that female song may have a similar function to male song. Lastly, in the presence of anthropogenic noise, the ability to discriminate between individual females decreases
significantly. With the urbanization of the natural world increasing over time, it is important to recognize how anthropogenic noise impacts communication in species that communicate acoustically, such as the black-capped chickadee. Specifically, focus should be directed to investigating female-produced song; although the function of this type of song remains under investigation, current research suggests that female song may hold importance to both sexes.
- Graduation date
- Fall 2021
- Type of Item
- Doctor of Philosophy
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