1. PART 4: BEHAVIORAL PLASTICITY
#16: DEVELOPMENT OF LEARNING IN SONGBIRDS I
behavioral plasticity
CH8: development of learning in songbirds
behavioral analysis of birdsong
singing in the brain
summary

2. PART 4: BEHAVIORAL PLASTICITY
#16: DEVELOPMENT OF LEARNING IN SONGBIRDS I
behavioral plasticity
CH8: development of learning in songbirds
behavioral analysis of birdsong
singing in the brain
summary

3. BEHAVIORAL PLASTICITY
adaptive responses to repeated experiences
experience  prediction of future events
information learned, stored & later retrieved
many forms, simple & complex
experiences via all sensory modalities
encoded in nervous system
cellular machinery
neuronal networks
behavioral plasticity ~ neural plasticity
nature - nurture

4. DEVELOPMENT OF LEARNING IN SONGBIRDS
vocal communication
territory
warning
breeding ?
highly diverse songs
studied to learn about
how animals communicate
learning & memory

5. DEVELOPMENT OF LEARNING IN SONGBIRDS
28 orders, 163 families, < 2000 genera, ~ 9000 spp.
~ 4000 songbird spp.
most work on song done with 3 spp.
white-crowned sparrow (Zonotrichia leucophrys)
zebra finch (Poephia guttata)
canary (Serinus canaria)

6. DEVELOPMENT OF LEARNING IN SONGBIRDS
mostly on perches (not ground)... more effective
rich in sp.-specific & social information
huge variety among bird spp.
1 invariant song
~ 100 songs
geographic dialects
learning... for many spp.
must hear sp.-specific critical time
normal development, under hormonal control

7. BEHAVIORAL ANALYSIS systematics of birdsong began early (Darwin)
lab studies in 1950s
methodology
framed important questions

8. WHAT’S IN A SONG ? accoustic structure
time-frequency sound spectrograph  visualize
song consists of punctuated sound units
note or element = 1 continuous sound
can have varied internal structure
syllable  2 notes
phrase  2 syllables or
can be 1 syllable / critical position
syntax = timing, order,  song specificity

9. WHAT’S IN A SONG ?
accoustic structure

10. WHAT’S IN A SONG ? dialects (eg., white crowned sparrow)
same song, different location

11. WHAT’S IN A SONG ? vocalization mechanism
respiration-driven... breathe between syllables
sound from syrinx (~ human larynx)
vibration of syringeal tympaniform membranes

12. SONG LEARNING in many spp. only  sing initial studies (chaffinch)
isolated young s
played tapes of adult  song
observed that young s
could imitate recording of species-typical song
no exposure  songs very simple
exposure as adult  songs abnormal
 learning by specific age
some birds (eg., canaries) not age-limited
open-ended learners

13. SONG LEARNING stages of song learning similar in most songbirds
temporal variation
1st, make subsong
~ baby talk
part of development, only in spp. that learn
2nd, make plastic song
1st evidence of imitation & song rehearsal
sp.-specific characteristics recognizable

14. SONG LEARNING timing of learning, different phases, can overlap
sensory: critical / sensitive, must hear song
sensorimotor: subsong & plastic song phases
crystalized: song fully developed

15. SONG LEARNING duration & timing of phases varies
age-limited learners (B), phases can overlap

16. SONG LEARNING duration & timing of phases varies
age-limited learners (B), phases can overlap
seasonal-closed learners (A), phases separated

17. SONG LEARNING duration & timing of phases varies
age-limited learners (B), phases can overlap
seasonal-closed learners (A), phases separated
open-ended learners (C), overlap & repeat
may only learn as juveniles & recall...

18. SONG LEARNING timing differences within same species, related to
length of breeding season
probably triggered by photoperiod

19. SONG LEARNING what closes the learning-critical time window ?
in Zebra finches...
critical period ~ 65 days in presence of  father
> 65 days in presence of s

20. SONG LEARNING what closes the learning-critical time window ?
critical period in Zebra finches...
~ 65 days in presence of  father
> 65 days in presence of s
influence of tutors... live > taped
not fixed time window
social interaction & tutor variation influence
sensitive rather than critical window  flexibility

21. SONG LEARNING imitation, improvisation & invention
not purely imitation of  father
swamp sparrows  ~ 200 syllables
1/3 imitated
36 improvised (variations)
> 1/3 invented (novel)
imitated 1st  improvised & invented later

22. SONG LEARNING imitation, improvisation & invention
creative process, can combine multiple songs

23. SONG LEARNING imitation, improvisation & invention
crystalized song is subset of plastic song syllables
trial & error use ?
action-based
learning
some birds may
sing songs in the
order they were
learned

24. SONG LEARNING what is learned during sensory phase ?
studied with play-back of taped or synthetic songs
innate preferences
species-specific > other

25. SONG LEARNING what is learned during sensory phase ?
studied with play-back of taped or synthetic songs
innate preferences
sp.-specific > other song
live non-specific > taped sp.-specific song
non-specific father > live sp.-specific song but with no visual... multimodal sensory critical – context
sp.-specific > non-specific  physiological response (eg., heart rate) – internal mechanism
use innate + learned / experienced information

26. SONG LEARNING learning a foreign song... what is not innate
eg., sympatric sparrows, many song differences
normal
isolated
tape-trained
deaf

27. SONG LEARNING learning a foreign song... what is not innate
tape-trained... sp. specific > non
mixed taped songs:
swamp sparrows used ~ syllable phonology
song sparrows used syllable phonology, syntax & song tempo... could learn
swamp sparrow songs in their own syntax
own syllables in swamp sparrow pattern
but not normal swamp sparrow song
 hear, articulate but use perceptual filter

28. SONG LEARNING innate song... what is not learned isolated birds
sing abnormal songs
some sing recognizable isolate or innate songs
eg., swamp sparrow
can also learn rest of song
 isolation not  learning

29. SONG LEARNING innate song... what is not learned
aspects of innate songs develop normally > others
duration, tonality, frequency range OK
syllables (words!) NOT
 certain aspects of song innate, others learned
repertoire size (# of songs) innate

30. SONG LEARNING auditory feedback & song templates
how does singing begin in sensorimotor phase ?
feedback ?... test by deafening (remove cochlea)
before subsong... tutoring does not work
accesses own memory through hearing
 auditory feedback critical
very different song from
isolated & deafened birds
no song memory at all
song template matching
either innate or learned ! (... what... where... ?)

31. SONG LEARNING auditory feedback & song templates feedback ?...
initially thought not critical for song maintenance
deafening after crystallization
no effect ?...
after some time
 syllables
phonology of syllables changes
 can be critical for development & maintenance

32. SEXUAL DIMORPHISM & HORMONAL REGULATION
in most songbirds... only s sing, sexual dimorphism
neuronal basis of song ~
brain polymorphism ?
in (eg., canaries) hormone
levels correlated with
breeding season
gonad size
song, 1/~ new syllables
castrated s do not
learn complete song

33. SEXUAL DIMORPHISM & HORMONAL REGULATION
steroid hormonal control
 s, stimulate song ~ s,  repertoire
castrated s, retarded song development
+ hormone  crystallizes song
– hormone  loss of crystallized song

34. SEXUAL DIMORPHISM & HORMONAL REGULATION
responses to hormonal treatment variable across spp.
development of language learning in birds ~ humans
critical time windows
stages
dependent on auditory feedback

35. BREAK