Wildlife monitoring of two miscanthus and two reed canary-grass fields in Herefordshire, England was carried out in 2002, 2003 and 2004 to investigate the ecological impact of perennial biomass grass crops on ground flora, small mammals and birds. Quadrats were used to record percentage ground vegetation cover within and around the periphery of each crop. Small mammals were sampled by live trapping using Longworth traps. The common bird census technique was used to monitor populations of birds. Miscanthus fields were richer in weed vegetation than reed canary-grass or arable fields. Bird use of the biomass crop fields varied depending on species. There were considerably more open-ground bird species such as skylarks (Alauda arvensis), lapwings (Vanellus vanellits) and meadow pipits (Anthus pratensis) within miscanthus than within reed canary-grass fields. There was no particular crop-type preference by the small mammal species, but rather a preference for good ground cover and little land disturbance, which was provided by both biomass crops. Ground flora, small mammals and most of the bird species (except open-ground birds) were found more abundantly within field margins and boundaries than in crop fields indicating the importance of retaining field structure when planting biomass crops. The miscanthus work relates entirely to young crops, which may be representative of part of the national crop if large areas are cultivated for rhizomes. The findings from the current project indicate that perennial biomass grass crops can provide substantially improved habitat for many forms of native wildlife, due to the low intensity of the agricultural management system and the untreated headlands. (c) 2006 Elsevier Ltd. All rights reserved.