Avian%20Mating%20Systems

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Avian Mating Systems Table 13-1 Monogamy
90 Polygamy Polygyny 2 Resource
defense Female defense Male-dominance Polyandry
1 Polygynandry 1 Promiscuity 6
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Behavioral Monogamy - most prevalent
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What leads to different strategies? Why
Monogamy?
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But extra pair copulations common in many
behavioral monogamous birds
EPCs vs EPFs Why? Direct Genetic
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Polygyny Resource defense - Redwinged
blackbirds
Inter vs. intra sexual selection
Nice territory!
Look at those epaulets!
Orians Polygyny Threshold Model
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• Polygyny
• Female defense (Harem) Grackles
• Wild Turkeys winter flock
• sibling males and
• harems of 4 -7 females

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Polygyny Male hierarchy lekking
Open area grouse - Sage grouse, prairie chickens
, manakins
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Polyandry Sequential phalaropes Simultaneo
us spotted sandpiper and jacanas
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Promiscuity
Forest grouse are solitary Ruffed Grouse, Blue
grouse
Hummingbirds
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The Ruff and multiple mating male strategies
Territorial Homozygous recessive Territorial
Shorter-lived 89 of copulations if with a
sattellite
Satellite Heterozygous Non territorial Longer
lived 11 copulations
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What leads to different strategies? Polygyny /
Promiscuity and lekking? OSR Hot spots Hot
shots Female preference Polyandry? OSR Clutch
Size Limitations?
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Increasing variance in reproductive success
leads to increased sexual selection
Promiscuity gt Polygyny Polyandry (reversed SD)
gt Monogamy
100
of males contributing genes
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Species
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Convergence (sort of) in African widowbirds
Shabby epaulets!
Run-away selection Based on female
preference linked to male trait
What a tail!!
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Sexual selection can lead to ever more elaborate
displays in plumage
Hummingbirds Neotropical and Nearctic
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Birds of Paradise - Australasia
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In some cases, both sexes display ornament,
though males may be larger
Black-billed Magpie
Scissor-tailed Flycatcher
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Hypotheses about sexual selection for these
traits?