Class Notes (837,550)
Canada (510,314)
Psychology (5,220)
PSYCH 2TT3 (28)
Lecture

bird songs.docx

20 Pages
65 Views
Unlock Document

Department
Psychology
Course
PSYCH 2TT3
Professor
Brett Beston
Semester
Winter

Description
March 11 , 2013 Psych 2TT3: Animal Behaviour Bird Song Bird Song - why bother? - how do birds sing? - Why do animals sing? - Is bird song innate or learned? - How do birds elarn how to sing? - Why do some birds learn how to sing? Bird Song – Why Bother? - vocal signals are ubiquitous - birds a classical model - vocal learning occurs only in 3 mammal & 3 bird taxa - vocal learning has allowed the evolution of language - neuroscience and evolution - most birds sing however if we look at all the different varieties of birds, only 3 of them actually learn something throughout their lifetime - this means all other orders have innate song behaviour - what is the benefit of learning in certain occasions vs. not learning - what are the proximate causes? What is Sound? - sound are pressure waves traveling through a medium - in air (and water) molecules are packed together at different densities, depending on the air pressure - sound pressure waves are relative to the ambient air pressure - alternative pressure waves or particles Ambient Air Pressure - differences in air pressure - string vibrating back and forth creates differences in air density or pressure - low pressure are less densely packed than high pressure - as a result of vibrating string we get oscillations of high and low density A Sound Wave - height is the amplitude = loudness or volume - frequency, how often or how tightly spaced are the air packets, includes peak and valley = pitch, the tighter the waves the higher the pitch - only in pure tones Complex Waveforms - sine waves do not occur in nature - they must be artificially created - naturally occurring sounds are complex waveforms - no indication of a pattern - you can have two different people say the exact same thing yet the characteristic of sounds would be very different Sonograms - used to represent sound - looks at frequency - at the bottom is digital representation of sound waves - above is the actual sonogram - we characterize amplitude and frequency change - frequency is on the y-axis, the higher the bands, the higher the frequency - amplitude is based on the darkness of the dots - red specs represent sounds that are so loud that have actually saturated the recording machine - white crowned sparrows derived from different population have variation in the sound that they produce - can identify where a bird is from and be able to replicate the sound - very important to studying song The Larynx (Humans) - organ in our throats which allow for sound production The Syrinx - special membranes (MTM) vibrate when air from lungs is forced over them - two passages in which air can pass - medial membrane: contractions can change the articulation of sound - sounds are coming from two different tubes means that we can produce two different sounds at the same time, can sing continuously - found deep in the chest - can produce two different notes simultaneously - by alternating between high and low notes the song can carry very complex messages - signals originated somewhere else in the brain Song Control in the Brain - using fMRI scan - different regions involved in learning and production of song - production of song: the higher vocal center  dense collection of neurons  sends information down through pathway of connections  branding the RA (robust nucleus)  information is then sent from RA to nXIIts  hypo glosal nerve (nerve 12), information is sent to tracial syrinx - if you damage these areas you completely disrupt the production of song - we can also make recordings of songs and trace neural firing that starts in the higher vocal center - motor: HVC, RA and nXIIts - learning: LMAN (lateral magnocellular nucleus of the anterior neo) and area X 21 Century Research - recording from individual neurons - monitoring gene expression - evolutionary genomics of song and language Expression of the ZENK Gene in Canaries - expression is linked to activity in only certain areas - expression of gene ZENK following exposure to certain sounds - ZENK is labelled - Canaries have been reared under certain conditions - Silence: only sparse distribution of ZENK expression, not being active - Hearing only, cannot produce song: more diffuse expression of ZENK but not particularly centralized in any way - We only see expression of ZENK in song production - Singing only: although a bird may be capable of producing sound they don’t get any feedback and cannot go through trial and error - When they can hear and sing we see concentration of ZENK in the LMAN, the only case that can actually lead to learning Individual Neurons - in HVC: activation of just a few neurons - RA: leads to amplification of signal in RA, lot more activation, RA is not just a relay station - Muscle activity: in vocal cords - Songogram: measure and record the actual production of sound In Birds, Who Sing? - typically only males sing  genetic (chromosomes)  males ZZ  females ZW  which translate into environmental differences in the birds brains  environmental (hormones)  if we look at chicks hatching in the early developmental stages before maturation, the circulation of hormones influences brain development  high levels of estrogene increase song learning ability The HVC (Higher Vocal Centre) is Larger in Males than Females - equal density at ten days - decrease in females brain - increase in males brain - subject females to estrogene treatment eliminates reduction in density of HVC neurons - strong role in preventing cell death Because of Sex Differences in Neuronal Death Rate - role of estrogene is preventing cell death Males have a Larger RA - in a male it is roughly 5 times the size - seems to vary between sexes as a result of neurological differences Song Repertoire is Positively Correlated with HVC Volume - positive correlation between HVC volume and the number of songs they are able to produce Why do Animals Vocalize? - what does an animal gain as a result of being able to vocalize - how does producing more songs help them? - How it plays a role in attracting females and competition between other males for resources and territories - In some species, both sexes produce vocal signals - Is vocalization used:  For social interactions?  For sensing the environment  Intentionality: warning calls in prarie dogs  Navigating their environment  Birds can do a combination Why Sound? - better than vision in poor lighting and places with obstacles (forest) - humans depend highly on vision - limited ability to see in a forest, a vocalization is a form of communication with indicates whereabouts without the need for visual stimuli, and can communicate possession - sound is useful when visual information has been degraded Attracting Mates? - how does singing correspond to different aspects of mating When do Birds Sing? - frequency of song in sedge warbler and reed warbler - there is seasonal variation in song production - as we get into may there is a large peak in song production - and decreases and falls to baseline levels in june/july - male singing precedes the laying of eggs in a nest - how does finding a mate affect ability to sing - dawn chorus: density of air, so the sound travels the furthest it can possibly go and that is when they sing the most - after pairing they stop song production - in 2 european warblers, singing starts 6-12 days after arrival - singing stops or is limited after pairing Experimentally Inducing Birds to Sing in Great Tits - remove females from great tit territories - record singing by the males - increase song production w
More Less

Related notes for PSYCH 2TT3

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit