Chapter 8: Part 2 Flashcards
Syrinx
- The vocal sound‐producing organ in birds
- A cartilaginous expansion covered by muscles, the syrinx lies at the lower end of the trachea where it branches into two bronchi before entering the lungs
- 3 types: tracheal, bronchial, and tracheobronchial
tracheal syrinx
- thick syringeal muscle surrounding the sound producing membrane (throat area)
- splits into two even bronchus
Bronchial syrnix
- only found in the Oilbird!!
- membranes of throat go past the trachea into the bronchi
- thinner muscle surrounding
- splits into two pathways earlier on, pinch in the middle of them
tracheobronchial syrnix
- most common type (in songbirds)
- thick syrinx muscle
- pessulus in middle of end of trachea, before splitting into two even bronchi
What is the function of the external and internal labia of the tracheobronchial syrinx?
- sound producing membranes
- air going out causes a vibration in trachea
Understand how the trachea, larynx, and hyoid apparatus influence sound production
Song learning
- Avian vocalizations can be inherited, learned, or invented
- Birds in a few groups (songbirds, parrots, hummingbirds) learn during vocal development
Understand how birds reared in isolation may or may not develop a normal song
- example: Gray Catbird
- only vocalizations in lab are the ones birds produce, no males around
- vary greatly from wild-type/normal song
Understand how birds reared in isolation may or may not develop a normal song: second!
- example: White-crowned sparrow
- wildtype/normal call has various notes, repeated bits
- isolated bird has one note song it repeates in various cuts
Sensory acquisition phase
- auditory experiences with external models or tutors refine the innate template during a physiologically based sensitive period
- can be affected by outside sources
Sensorimotor phase
- practice and feedback mold initial subsong elements into plastic song, which is then refined into crystallized song by matching components to the template produced in the first phase
- “practice makes perfect” stage
Name the typical stages of song learning in oscine passerines
- Critical learning period
Silent period
Subsong period
Adult song
example: Bewick’s wren
Critical learning period
- The early period during which information is stored for use in later stages of learning
- In most species, the critical learning stage lasts less than a year - sometimes much less
- In the sensory acquisition phase
Silent period
- The long period (as long as eight months) in which syllables learned during the early critical learning period are stored without practice or rehearsal
Subsong period
- Practice period analogous to infant babbling
- Bridges the gap between the perceptual and sensorimotor stages of vocal learning
- A period of practice without communication; perhaps subsong is a form of vocal play
- Sensorimotor phase
Describe how males adapt to local songs
- I believe example is the Indigo Bunting?
- match the song details of an immediate territorial neighbor
- perpetuates the local neighborhood of songs
- develops type of dialect overtime
Song adaptation of Song Sparrow
- After establishing a territory, they learn some of the common neighborhood song types, thus ensuring that they share some song types with all or most of their territorial neighbors.
- various individuals can have various levels and ranges of bird song abilities
Marsh wrens vs. Sedge wrens
- marsh wrens: Stable communities, Shared identical songs
- sedge wrens: Nomadic, unpredictable in their breeding locations; Neighboring males are often strangers; Lots of improvisation
Suboscine Vocal Development
- Suborder Tyranni, suboscine birds
- About a thousand suboscine species reside in the New World (antbirds, antpittas, woodcreepers, cotingas, and flycatchers)
- A handful of suboscine groups (broadbills, pittas) live in the Old World
Alder Flycatcher vs. Willow Flycatcher: Suboscine development
- Essentially identical in appearance
- Only reliable way to identify them in the field is by their songs and calls
Experiment of Alder and Willow Flycatchers
- Trained with opposite songs
- Unlike songbirds, these young flycatchers developed perfectly normal songs of their own species
- The young flycatchers did not imitate the “wrong” songs they heard
- Song development of most suboscines may resemble that of these flycatchers
three wattled bellbird
- Individuals alter their songs from year to year, with all the birds in an area making the same change in concert
Vocal development in non-passerines
- Psittacids
- ability to imitate human speech
- Wild birds also imitate the vocalizations of other individuals of their species
Hummingbird songs
- Anna’s hummingbirds: isolated birds develop highly abnormal songs
- Sparkling Violetear: songs of territorial neighbors are very similar