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

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

 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 brain  Best 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

WinterSpring Male Female 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 dangers  Songs 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 out  Males (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