The basal ganglia (BG) play an essential role in shaping vertebrate behavior, ranging from motor learning to emotions, but comprehensive maps of their canonical synaptic architecture are missing. In mammals, three spatially separated main neuronal pathways through the BG were described - the direct, indirect, and hyperdirect pathways - that work together to orchestrate behavior. In songbirds, the cell types associated with these pathways appear intermingled in the basal ganglia nucleus Area X, essential for song learning. Here, we describe the first vertebrate basal ganglia connectome, comprising almost 10,000 of high-quality automated neuron reconstructions connected by about 20 million synapses. Based on direct anatomical measurement of synaptic connectivity, we can confirm that a direct, indirect and hyperdirect pathway can be traced through Area X. Remarkably, detailed connectivity analysis revealed no clear MSN subpopulations, and bulk synaptic connectivity suggests that the indirect pathway might be barely functional in its classical sense in Area X. Furthermore, we find strong synaptic interconnectivity and recurrency on the network level, challenging many contemporary BG models that follow simple feedforward-schemes.Figure: a) schematic of mouse basal ganglia. b) Schematic of mammalian basal ganglia pathways. c) Schematic of song learing pathway including the avian basal ganglia nucleus, Area X. The zoom in shows the volume EM dataset with two reconstructed neurons. d) Blender renderings of example cells from the connectomics dataset. The cell types are involved in the basal ganglia pathways.