Willow ptarmigan diet inferred from DNA metabarcoding of faeces

DNA metabarcoding of willow ptarmigan faecal pellets was used to examine seasonal and annual variation in diet between the sexes of this herbivorous alpine bird. Diet data is coupled to snow cover and vegetation phenology metrics in order to place diet variation in the context of changing climate. Due to the physical similarity between willow ptarmigan and rock ptarmigan feces, data is also provided for 22 rock ptarmigan fecal samples that were not included in further data analysis.