we’ll listen to some songs in the lab room (wsb) while i lecture chapter 8 - vocalizations
TRANSCRIPT
We’ll listen to some songs in the lab room (WSB) while I lecture
CHAPTER 8 - VOCALIZATIONS
Vocal communication very complex and rich Songs for mate
attraction Songs against rivals
One song serves both in many cases
Calls to keep in contact with others
Calls to alert others to danger
Calls that transmit information on need
VOCALIZATIONS
European Starling (Sturnus vulgarus) belting it out
VOCALIZATIONS
Keep in mind, many species do not sing.
Passeriformes are a group that does sing and has been well studied.
Other groups sing (e.g., Hummingbirds) but they have not been as well studied.
When the book is talking about song, it’s talking about Passeriforme song
Superb Fairy-wrens (Malurus cyaneus) female (left) and male (right)
VOCALIZATIONS – SONG COMPONENTS
Physical structure of sound influences what the listener hears Interfering noise and dampening structure of the
environment can curtail sound What the call or song is trying to convey and who the
audience is influences the type of sound Location calls will be easy to discern and locate caller Alarm calls less easy to determine callers location
(because then the predator can too!) Background sound having a significant influence on bird song
Several studies have looked at human noise pollution and bird song
VOCALIZATIONS
VOCALIZATIONS
Two different types of alarm calls from a single species, what the senders want the receivers to do differs as does the sound of the calls
Short, intense, easily located call
‘Seet’ call – very hard to detect and locate
Birds produce sounds by moving air over /through a structure Similar to mammals in this regard, but not using vocal
cords Birds use a syrinx
Structure located at junction of the two primary bronchi Air vibrates while passing through the syrinx, produces sound Air from intraclavicular air sac used This is a two-sided structure and both sides can produce song
simultaneously Controlled by syringeal muscles
VOCALIZATIONS - ANATOMY
VOCALIZATIONS - ANATOMY
VOCALIZATIONS - ANATOMY
VOCALIZATIONS - ANATOMY
Air flow through syrinx source of sound/song Can be surprisingly
complex Can allow a single
bird to sound like 2+
One note or song can be produced using both sides Cardinals,
increasing whistle started on one side and finished on other
VOCALIZATIONS
Male Northern Cardinal (Cardinalis cardinalis) singing
How is song production controlled – the brainBest studied in songbirds (Passeriformes, the most
prodigious singers) Song control system (SCS)
Series of brain nuclei Sex and seasonal differences in volume Neurogenesis and neuron death occurs regularly Influenced by steroid hormones Controls learning, memory, and production
VOCALIZATIONS - CONTROL
VOCALIZATIONS - CONTROL
VOCALIZATIONS - CONTROL
Winter SpringM
ale
Fem
ale
HVC in male and female cardinals
Song can be ‘hard-wired’ in some species Brown-headed Cowbirds (Molothrus ater) do not learn
song from parents, not even raised by other cowbirds Song can be learned from parents or other tutors
Some species have specific learning periods Times vary and may be related to dialects
Some species have open-ended learning Northern Mockingbirds (Mimus polyglottos) learn their whole
lives
Two phases of learning exist where young birds (typical species, not mimics) have to hear and be able to practice their song
VOCALIZATIONS - LEARNING
VOCALIZATIONS
Birds, like people, have dialects or regional variation in song May be due to
variations in genetics, local mate choice, differences in habitat structure
Part of learning may be keeping the template open until dialect heard Want to sound like
everyone else
VOCALIZATIONS
White-crowned Sparrow (Zonotrichia leucophrys) dialects
What are birds saying to each other?Calls and songs can differ in their information
Contact or location calls can keep flying (migrating) or foraging flocks together
Contact or location calls can help mated pairs know each other’s locations
Calls can be used to alert others of potential dangersSongs have been well studied for their
information Songs can be used to display territory boundaries and
keep others out Songs can attract a mate
VOCALIZATIONS - CONTENT
VOCALIZATIONS
Begging calls in nestlings can stimulate parents to feed them Studies have
addressed honesty in the intensity of calls
Calls can also be a signal predators use to find nests
Some species (European Cuckoo, Cuculus canorus) use call to dupe others
VOCALIZATIONS
Begging calls usually high-pitched (harder to locate sound source) and insistent
Song on territories indicated ownership Can be used to
define boundaries Can be used to keep
interlopers outMales (typically)
respond strongly to challenges ‘Dear enemy’
hypothesis ‘Nasty neighbor’
hypothesis
VOCALIZATIONS
Male Red-winged Blackbird (Agelaius phoeniceus) sings on territory to announce ownership
Song used in many instances to acquire and defend a mate Females of many species show behaviorally their
attraction to certain songs Studies with White-crowned sparrows and protein deprivation –
altered song and altered SCS Quality of the song can mean something about quality of bird
Additional studies have found even more co-variations with quality
Song argued to be energetically expensive Long, complex song can be sign of high quality male or territory Importance of the ‘Dawn Chorus’
VOCALIZATIONS
What about females? Females of some
species sing Most duet with mates Some sing alone
Female songbirds possess an SCS In most it’s smaller, less
developed SCS appears to
function in song discrimination
Testosterone has a role to play
VOCALIZATIONS
Studies with female Northern Cardinals show females new in pairs sing more and that the female SCS isn’t much different than male SCS