Extended Family System in a Communal Bird

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Science  27 Feb 1981:
Vol. 211, Issue 4485, pp. 959-960
DOI: 10.1126/science.211.4485.959


The genealogical structure of an extended family system in a nonprimate species is described. In Mexican jays, social units are more complex genealogically than in most other communal birds and may contain grandparents, uncles, aunts, and cousins in addition to parents and older siblings. The average relatedness within the units varies greatly, and is lower than would be expected for a highly social bird.