&gt; Is this sufficient evidence for you?<p>Sufficient if we just consider birds, of course. But what do we discuss here? It started with the<p>&quot;There are plenty of species which are well documented to have monogamous relationships&quot;<p>claim and all I see is birds and birds.<p>Edit: thanks for finally answering below my question &quot;how much in percents is that &quot;plenty  of species&quot;?&quot; Your answer is &quot;90% of birds.&quot; The rest of discussion would have been unnecessary, especially quoting some three specific birds as the answer. I also agree with yours &quot;the average sexual behaviors across all species doesn&#x27;t give you much insight.&quot;