Science. 1979 Nov 30;206(4422):1103-5. doi: 10.1126/science.206.4422.1103.
Acorn woodpeckers (Melanerpes formicivorus) live in family groups within which more than one female may lay eggs communally in a single nest. Communally nesting females are usually closely related and share evenly in nesting activities. Although birds of either sex may breed in their natal territory, reproductive inhibition of offspring by the presence of their parent of the opposite sex and dispersal by unisexual sibling units ensure that inbreeding between close relatives is rare.
橡果啄木鸟（Melanerpes formicivorus）生活在家族群体中，一个巢中可能有不止一只雌鸟共同产卵。共同筑巢的雌鸟通常具有密切的亲缘关系，并平等地参与筑巢活动。尽管雄性和雌性鸟类都可以在其出生地繁殖，但异性亲鸟的存在会抑制后代的繁殖，并且通过同性兄弟姐妹单位的扩散，确保了近亲之间的近亲繁殖很少发生。
