The hoatzin (Opisthocomus hoazin) is a South American herbivorous bird, that has an enlarged crop analogous to the rumen, where foregut microbes degrade the otherwise indigestible plant materials, providing energy to the host. The crop harbors an impressive array of microorganisms with potentially novel cellulolytic enzymes. Thie study describes the composition ofthe particle-associated microbiota in the hoatzin crop, combining a survey of 16S rRNA genes in 7 adult birds and metagenome sequencing of two animals. The pyrotag survey demonstrates that Prevotellaceae, are the most abundant and ubiquitous taxa, suggesting that the degradation of hemicellulose is an important activity in the crop. Nonetheless, preliminary results from the metagnome of the particle-associated microbiota of two adult birds show that the crop microbiome contains a high number of genes encoding cellulases (such as GH5) more abundant than those of the termite gut, as well as genes encoding hemicellulases. These preliminary results show that the carbohydate-active enzyme genes in the cropmetagenome could be a source of biochemical catalysts able to deconstruct plant biomass.