Co-localization patterns of neurotensin receptor 1 and tyrosine hydroxylase in brain regions involved in motivation and social behavior in male European starlings.

•Double fluorescent immunolabeling was performed for NTR1 and TH in male starlings.•NTR1 cells and TH cells were present in VTA, POM, PAG, and LS.•Co-localization of NTR1 and TH was seen in VTA only.•No labeling differences were found for birds in distinct seasonal conditions.•Interactions between NTR1 and dopamine in VTA may modulate starling behavior.