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

Behavioral Monogamy - most prevalent

What leads to different strategies? Why Monogamy?

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

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

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

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

Polyandry Sequential – phalaropes Simultaneous – spotted sandpiper and jacanas

Promiscuity Forest grouse are solitary Ruffed Grouse, Blue grouse Hummingbirds

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

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

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

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

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

Birds of Paradise - Australasia

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

Hypotheses about sexual selection for these traits?