They aren&#x27;t many bird species that mate for &quot;life&quot; procriate with other mates during the actual mating season but nest with their original mate.<p>It seems that there are 2 nearly opposite evolutionary drives one is that long term bonding increase the likelihood of offspring survivability and the other that promiscuous mating increases the overall group genetic diversity.<p>Some bird species that also present same sex bonding will have single sex bonds nesting and having another female lay eggs in their nest, other species that operate under more communal care for their offspring show behavior akin to what we would call adoption.