ABSTRACT: Vocal learning and neuronal replacement have been studied extensively in the songbird brain, but until recently, few molecular and genomic tools have been available for this work. Here we describe new molecular/genomic resources for songbird research. We made cDNA libraries from zebra finch (Taeniopygia guttata) brains at different developmental stages. A total of 11000 clones were sequenced from these libraries, representing 5870 unique gene transcripts. A web-based database has been established for sequence analysis and functional annotations. The cDNA libraries were not normalized. Sequence analysis revealed that a cDNA library made from brains at post-hatching day 30-50, when the song system goes through rapid development and birds learn to sing, shows the highest gene discovery rate. We grouped genes into functional categories according to the Gene Ontology classification and found that expression of the functional categories changed as the brain developed. We also identified five microRNAs whose sequences are highly conserved between zebra finch and other species. We printed cDNA microarrays and profiled gene expression in the HVC of both adult male zebra finches and canaries (Serinus canaria). Statistical Analysis of Microarrays (SAM) was used for data analysis. A subset of the differentially regulated genes was validated by in situ hybridization. The bioinformatic tools EASE and Ingenuity Pathway Analysis were used to identify over-represented functional groups and gene networks among the regulated genes. These resources provide songbird biologists with tools for genome annotation, comparative genomics, and microarray gene expression analysis. Keywords: HVC, songbird, cDNA microarray, gene expression Overall design: We compared gene expression in HVC and whole-brain samples in adult male zebra finch and canary. Three birds of each species were used. For each bird, dye-switching was performed.