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Courtship and Mating •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) GBHs 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 its 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) theyre 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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