Social affiliation relates to tyrosine hydroxylase immunolabeling in male and female zebra finches (Taeniopygia guttata)

► Tyrosine hydroxylase (TH) labeling was examined in same- and mixed-sex finch pairs. ► TH in nucleus accumbens (Ac) was denser in members of mixed-sex pairs. ► TH density in mesolimbic and social brain areas related to affiliative behaviors. ► Behavior/TH correlations for Ac and ventral tegmental area were subregion specific. ► Affiliative behavior was similar in same- and mixed-sex zebra finch pairs.