The passage highlights the fascinating differences in reproductive habits among birds, using the condor and ostrich as examples. While the condor lays only a couple of eggs, the American ostrich lays many more, yet the condor can still be more prevalent in its habitat. This illustrates that quantity of eggs does not necessarily correlate with the abundance of a species in a given area.

Additionally, the text mentions the Petrel, which lays a solitary egg but is regarded as one of the largest birds. This comparison underscores that size and reproductive output among bird species can vary significantly, calling into question conventional expectations about abundance and size in the animal kingdom.