1. Avian Mating Systems
Table 13-1
Monogamy 90%
Polygamy
Polygyny 2%
Resource defense
Female defense
Male-dominance
Polyandry 1%
Polygynandry 1%
Promiscuity 6%

2. Behavioral Monogamy - most prevalent

3. What leads to different strategies?
Why Monogamy?

4. But extra pair copulations common in many behavioral monogamous birds
EPC’s vs EPF’s
Why?
Direct
Genetic

5. Polygyny – Resource –defense -
Redwinged blackbirds
Inter vs. intra sexual selection
Nice territory!
Look at those
epaulets!
Orians’ Polygyny Threshold Model

6. Polygyny –
Female defense (Harem) – Grackles
Wild Turkeys – winter flock
sibling males and
harems of 4 -7 females

7. Polygyny – Male hierarchy
“lekking”
Open area grouse - Sage grouse,
prairie chickens , manakins

8. Polyandry
Sequential – phalaropes
Simultaneous – spotted sandpiper and jacanas

9. Promiscuity Forest grouse are solitary Ruffed Grouse, Blue grouse
Hummingbirds

10. The Ruff and multiple mating male strategies
Satellite:
Heterozygous
Non territorial
Longer lived
11% copulations
Territorial
Homozygous recessive
Shorter-lived
89% of copulations if with a sattellite

11. What leads to different strategies?
Polygyny / Promiscuity and lekking?
OSR
Hot spots
Hot shots
Female preference
Polyandry?
Clutch Size Limitations?

12. leads to increased sexual selection
Increasing variance in reproductive success
leads to increased sexual selection
Promiscuity > Polygyny = Polyandry (reversed SD) > Monogamy
100
% of males
contributing
genes
Species

13. Convergence (sort of) in African widowbirds
Shabby epaulets!
Run-away selection –
Based on female preference
linked to male trait
What a tail!!

15. Sexual selection can lead to ever more elaborate displays in plumage
Hummingbirds Neotropical and Nearctic

17. Birds of Paradise - Australasia

18. In some cases, both sexes display ornament, though males’ may be larger
Black-billed Magpie
Scissor-tailed Flycatcher

19. Hypotheses about sexual selection for these traits?