Dataset used to estimate annual abundance indices and trends for UK butterflies in gardens, covering the period 2007 to 2020. Data have been collected as part of the British Trust for Ornithology (BTO) Garden BirdWatch (GBW) survey. GBW is a structured, citizen science monitoring programme whereby volunteers record weekly abundances of various bird, invertebrate, mammal, reptile and amphibian species in (predominantly suburban and rural) gardens. See www.bto.org/gbw for further information about the survey. This dataset has been pre-filtered to meet criteria for inclusion in the modelling of butterfly species trends, as described by Plummer et al 2023. Please refer to the 'readme' file for further details. We would also greatly appreciate if you could fill out this very short form to tell us how you intend to use these data. Thanks in advance!