 Males sing constantly as the breeding period approaches and perform less often once pairs have bonded . In the presence of a female , a male sometimes flies to his nest and sings from the entrance , apparently attempting to entice the female in . Older birds tend to have a wider repertoire than younger ones . Those males that engage in longer bouts of singing and that have wider repertoires attract mates earlier and have greater reproductive success than others . Females appear to prefer mates with more complex songs , perhaps because this indicates greater experience or longevity . Having a complex song is also useful in defending a territory and deterring less experienced males from encroaching . 
 Males sing constantly as the breeding period approaches and perform less often once pairs <a href='been_done' title='1'><mark>have</mark></a> bonded . In the presence of a female , a male sometimes <a href='uninflect' title='2'><mark>flies</mark></a> to his nest and sings from the entrance , apparently attempting to entice the female in . Older birds tend to have a wider repertoire than younger ones . Those males <a href='null_relcl' title='3'><mark>that</mark></a>engage in longer bouts of singing and that <a href='got' title='4'><mark>have</mark></a> wider repertoires attract mates earlier and <a href='got' title='5'><mark>have</mark></a> greater reproductive success than others . Females appear to prefer mates with more complex songs , perhaps because this <a href='uninflect' title='6'><mark>indicates</mark></a> greater experience or longevity . Having a complex song <a href='drop_aux' title='7'><mark>is</mark></a>also useful in defending a territory and deterring less experienced males from encroaching . 
Males sing constantly as da breeding period approaches and perform less often once pairs done bonded . In the presence of a female , a male sometimes fly to his nest and sings from tdaentrance , apparently attempting to entice the female in . Older birds tend to have a wider repertoire than younger ones . Those males engage in longer bouts of singin and that got wider repertoires attract mates earlier and got greater reproductive success den others . Females appear to prefer mates witt more complex songs , perhaps because dis indicate greater experience or longevity . Having a complex song also useful in defending a territory and deterring less experienced males from encroaching .