L4 - Birdsong Flashcards
What class are birds?
Aves
How many orders, families, genera and species of bird are there?
28 orders, 163 families, 2000 genera, ~9000 species
How many species of birds are songbirds?
~4000 (about 50%)
What is the difference between a bird song and bird call?
Call: usually a short and simple vocalization that signals flight or danger and is produced throughout the year
Song: tends to be a long and complex vocalization produced during a breeding season
What is it called when an individual bird can sing more than one version of a song type?
A repertoire
What are the structural parts which make up a birdsong?
Notes/elements:
- Continuous mark on the spectrogram
- Simple continuous narrow frequency band
- Complex frequency and amplitude
Syllables:
- Composed of two or more notes clustered together
Phrase:
- Two or more syllables grouped together
- Could also be series of single notes/syllables
Syntax:
- Specific timing and ordering of notes, syllables and phrases
What is interesting about White-Crowned sparrow’s song?
They have dialects, can tell where a bird lives from it’s song
Which sex sings and why?
Depends on who competes to breed – usually males, sometimes both sexes duet
What selective pressures have driven evolution of birdsong?
Twin selective pressures have driven the evolution of song – female choice and male-male competition
In Barn Swallows, what does the length and frequency of the “rattle” part of their song correlate with?
Longer rattle - higher testosterone levels (therefore breeding success)
Higher frequency - healthier bird
What information is in a song?
- Presence of potential mate
- Individual identity
- Where he was born & raised
- Where is physically located at the time
- Whether or not he owns a territory
- His willingness to breed
- Condition
- Early environmental experience
- “Quality”
What does conspecific mean?
Within the same species
What does heterospecific mean?
Within different species
What did William Thorpe discover about chaffinch’s birdsong?
- Young males in isolation learn song by playing ‘tutor’ tapes of the conspecific song
- In absence of recorded song, develop abnormal song
- If recorded song is given after sexual maturity, chaffinch still develop abnormal song
- Showing innate predisposition to learn songs of conspecifics
What is the subsong?
Stage in song development when young birds produce rambling sounds variable in timing and pattern
What is plastic song?
Stage in song development - as birds grow older, assume posture produce sounds in discrete clusters & aspects of the temporal patterning of the adult song is detectable. First evidence of imitation & characterization of adult species-specific song. First stage at which rehearsal of previously learned songs begins
What is crystallised song?
Stage in song development when full song expressed with normal variations in volume, duration, syllabic structure, etc.
What are the three stages of song development?
Subsong, plastic song, crystallised song
What are the three song learning phases?
Sensory phase, sensorimotor phase, transition to crystallised song phase
Describe the sensory phase of song learning?
It is when auditory experience occurs. Must hear their normal species song from other adult birds. During this phase commits song to memory, but may not sing at this time. This is a critical/sensitive period in which auditory experience must occur
Describe the sensorimotor phase of song learning?
It is when vocal practice begins
Includes both the subsong and plastic song stages
What are the three categories birds fall in for learning a song? (to do with when they learn)
Seasonal closed learners
Age-limited learners
Open-ended learners
Two species of swamp sparrow overlap in territory - what happens to their birdsong as they get closer to crystallisation?
Initially their birdsong contains notes from both species but as they get closer to crystallisation the birdsong becomes species specific
Name the factors which go into a bird correctly learning their species birdsong
- Innate (genetic) factor
- Trained factor
- Social (interaction) factor
Which hormone has a negative correlation with the learning of new syllables?
Testosterone
What three parts of the brain are used in song production and make up the song production nuclei?
- Higher Vocal Centre (HVc)
- Robust nucleus of the archistriatum (RA)
- The tracheosyringeal portion of the hypoglossal nucleus (nXIIts)
What three parts of the brain are used in song learning? And which pathway is this?
- Area X
- Medial portion of the dorsolateral thalamus (DLM)
- Lateral portion of the magnocellular nucleus of the anterior neostriatum (LMAN)
- Anterior forebrain pathway
What is laterality?
When one side of the brain is (most) responsible for an action, behaviour or learning etc
Is there any laterality in birdsong? What is the evidence?
Yes
- When right side of brain was lesioned (lesion in HVc) the birdsong was very similar
- When the left side of the brain was lesioned (lesion in HVc)the new birdsong showed no resemblance of the original
What effect does the time of the year have on the size of the HVc and RA?
HVc and RA are 99% and 76% larger respectively in spring (singing vigorously) than in autumn
What effect does injecting females with testosterone have?
They will sing and have increased volume of HVc and RA
What is the relationship between size of HVc and sex bias in singing?
The bigger the HVc in a species of bird the higher the sex bias in singing
How many times did birdsong evolve?
2 or 3
Does injecting non-songbirds with testosterone cause them to start singing? And why?
No - because non-songbirds do not have the brain circuitry to be able to sing
