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