Chapter 8: Part 3

Question 1

auditory input pathway

Answer 1

• projects auditory input from the ears, via the auditory nerve and the brain stem, to the cerebrum

Question 2

posterior vocal pathway

Answer 2

• connects various cerebral vocal control centers (HVC, RA, etc.) to the brain stem and manages the motor control of vocalization

Question 3

anterior vocal pathway

Answer 3

• forms a loop of nonvocal forebrain regions and includes cerebral nuclei (LMAN [the lateral magnocellular nucleus of the anterior nidopallium], Area X, etc.)
• these are responsible for analysis of auditory input and acoustic output involved in song learning, social context, vocal syntax, and maintenance of song structure

Question 4

How is the songbird brain lateralized?

Answer 4

• The left hemisphere of the forebrain controls birdsong - specifically, learning and innovation in vocal repertoires
• The right cerebral hemisphere assumes control of the functions of the left hemisphere only if the left hemisphere is damaged

Question 5

Compare a songbird brain with a nonsongbird brain

Answer 5

Vocal production regions present
Vocal learning regions absent

Question 6

How does testosterone influence singing behavior?

Answer 6

• Seasonal changes in plasma testosterone concentrations in male Song Sparrows. Columns represent mean ± SEM (error bars) plasma testosterone concentrations in male Song Sparrows collected at each of the four sampling times (Smith et al. 1997).
• http://people.eku.edu/ritchisong/birdcommunication.html

Question 7

How do male and female songbird brains differ?

Answer 7

• males have strong presence of posterior and anterior pathways
• females have posterior vocal pathway present, while anterior vocal pathway is absent

Question 8

Individual variation

Answer 8

• example: eastern phoebe

Question 9

Individual Recognition

Answer 9

• Territorial males respond more aggressively (with greater song output) to playback of a stranger’s song than to playback of a neighbor’s song
• However, the focal male responds with equal aggression to neighbor playback if the songs are played at a location other than the border
• example: Bank Swallows, Parents use the distinctive calls of their offspring to locate them within large flocks of other young Bank Swallows

Question 10

Example of indvidual recognition in penguins

Answer 10

• Returning females call and await a return call from its mate, suggesting that pair members can recognize one another’s calls

Question 11

Dialects

Answer 11

• A consequence of vocal learning
• example: white-crowned sparrows all display different calls, but vocal learning in environment can cause this
• different call displays that show almost no similarity can lead to separation of population in environmental disaster, such as a fire
• creates subsections of bird dialects

Question 12

Geographic variation in bird songs

Answer 12

• example: marsh wren
• example: Blyth’s reed warbler, different song types found throughout species range
• Blue-winged and Chestnut-sided Warblers (little to a lot of variation)

Question 13

Cryptic Species

Answer 13

• examples: Watkin’s Antpittas and Chestnut-crowned Antpittas

Question 14

Vocal mimicry

Answer 14

• in 20 percent of passerines
• many open-ended learners: Enlarge their repertoires by learning and singing the songs and calls of other species
• examples: Northern Mockingbird and Gray Catbird

Question 15

Female song

Answer 15

• Song is more common in male birds, but females of hundreds of bird species also sing as part of their normal activities

Functions (same as males):
- Defend territories against members of both sexes
- For attracting and communicating with their mates
- For advertising their availability and condition

Question 16

Duets

Answer 16

• The members of a mated pair of birds communicate with one another frequently - in many species the communication includes vocal signals
• In some species: vocal exchanges are overlapping bouts of calling
• In others: involve coordinated singing (duets)