Courtship and Mating

With Diversions into Displays, Visual Communication & Plumage

 •Review mating systems

–Monogamy

•Territorial

•Colonial

–Polygamy

•Polyandry (usually serial)

•Polygamy

–Harems

–Leks

–Serial

•Mating requires?

–Fertile mates

–Synchrony

•Time

•Location

•Condition

–Cooperation

•Requires communication

–Visual & vocal

Visual communication (Chapter 9)

1)      Through displays -

a)      a ritualized behavior

b)      identity

c)      status

d)      intention

i)        play or fight

ii)       mate

iii)     take over territory

iv)     flight - how do flocks fly together?

e)      potential as a mate

2)      Helps

a)      resolve individual conflicts

b)      promote cooperation

i)        evolve in tandem with (each accentuates the other)

(1)   plumage ornaments

(2)   color patterns

(3)   usually feathers

(4)   but also

(a)    skin - booby

(b)   eyes - parrots

(c)    bill - toucan

(5)   posture

(6)   vocalization

3)      Plumage patterns

a)      1st conflict

i)        hide - cryptic

ii)       sometimes bold patterns conceal

(1)   ptarmigan

(2)   tanagers

iii)     camouflage

(1)   disruptive - break outline of body

(2)   countershading

(3)   white reflects ground color

(4)   more prominent in short-legged waders

iv)     be seen

(1)   uniform color of male cardinals

(2)   dark edging around a color - Hooded Merganser

(3)   geometric shapes

(4)   repetition

4)      Species recognition

a)      often head coloration -

i)        eyes

ii)       bill

iii)     facial skin     

iv)     feathers

b)      imprinting determines mating preference

i)        snow geese

ii)       birds in captive breeding programs

5)      Individual recognition

a)      depends on some variation in

i)        feathers

ii)       bill color

iii)     size

iv)     voice

b)      is this communication?

6)      Evolution of displays

a)      definition- combination of visual and vocal (or mechanical) signals and coordinated behaviors.

b)      communication reflects evolutionary heritage

i)        example

(1)   Pelicaniformes

(2)   Manakins - show overhead

(3)   Prum suggests behavior drives plumage enhancements - e.g. bird of paradise 

c)      ritualized behavior -

d)      non-signal behavior is incorporated into displays

i)        ritual/courtship feeding

ii)       feather erection

iii)     preening movements

iv)     increase efficiency and clarity of signals

v)      displays become precise

vi)     graded displays convey probability/intention

7)      Deciphering displays

a)      a challenge for ornithologists

b)      single display can have several messages and message varies with context

i)        GBH’s have 15 displays - show overhead

c)      Agonistic behavior

i)        includes threat and appeasement

d)      competition over something

e)      ritualized displays avoid physical contact/injury

8)      do birds tell the truth?

a)      threat displays are often bluffs

b)      appeasement usually signals flight

c)      mimicry in plumage - gain access to something

9)      Sexual selection

a)      Darwin talked of this

i)        Elaborate plumage and displays result of female choice?

ii)       but Red-winged Blackbirds it’s male-male competition; females choose the territory

iii)     but Long-tailed Widowbirds show opposite effect - female            

iv)     choice drives the system

b)      Good genes vs. Fashion Icons?

i)        why do females chose showy males?

(1)   they truly are genetically superior

(2)   they can lug the display around

(3)   they’re healthy - parasites effect comb in rooster

(4)   carotenoids – antioxidants (see TREE review)

ii)       arbitrary choice and runaway fashion

(1)  once females begin choosing showy males the process accelerates to extremes - birds of paradise  

Study questions for Chapter 9

 Define a display.

What are the functions of avian display?

Birdwatchers use plumage colors and patterns to identify species, what evidence suggests that birds use colors and patterns for the same purpose? Is there evidence to the contrary? Explain.

What is an intention movement?

Why would intention movements be a good evolutionary source of displays?

What is ritualization?

How does one look at phylogeny of behavior?

What is the advantage of stereotypy in ritualized displays?

Ritualization may enhance the contrast between postures. How is this advantageous?

Is contrast is advantageous, what function is served by graded displays?

How can we decipher the meaning of displays? What variables confound interpretation of displays?

Given a limited number of displays, what two different methods can be used for increasing the amount of information that can be communicated?

What is agonistic behavior?

Why use agonistic behavior?

What are common denominators of threat displays?

What are common denominators of appeasement displays?

What is the general progression of display types in courtship?

If threat displays do not always lead to attack, are they reliable indicators of aggressive intent?

Why might you expect submissive displays to be more reliable than threat displays?

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