Q. Infrequent additional pair paternity despite demonstrable extra-pair matings Do males exerts higher level control of fertilization? Zebra finches: 16% extra pair copulations, but only 2% fathered by extra-pair males Reed bunting: 55% of chicks fathered by extra-pair males what accounts for the variation in illegitimate offspring in different species? we don't know don Does extra-pair paternity increase a male's reproductive success? Seems obvious that males benefit from extra-pair copulations, right? The cuckolded only benefits at the expense of cuckolded perhaps benefits are washed away by loss of paternity in his own nest?