Background The problem of bird collisions on high speed lines (HSL) has increased significantly in recent years. Along with hazards related to rail infrastructures, high speed trains also pose an additional risk to birds. Both common and more sensitive species are at risk, and as a result of bird collisions on HSL, the populations of certain bird species are decreasing and becoming increasingly isolated. This includes some birds of prey, and birds linked to water bodies or to open and steppic environments, all of which are included in Annex I of the Birds Directive. An Infrastructure and Transport Strategic Plan, drawn up by the ministry of public works, proposes the introduction of more than 7 000 km of new high-performance lines during the period 2005-2020. This has important consequence for several Natura 2000 sites. Specifically, it is estimated that more than 1 000 km of the planned routes (more than 14.3% of the total length) will run through Natura 2000 sites, potentially affecting more than 192 protected areas (56 SPAs and 188 SCIs). Objectives The main objectives of this project are to: Develop a proposed methodology for the determination of optimum measures for protecting birds in new HSL areas, as well as a series of recommendations for the development of environmental monitoring programmes during the construction of new lines, and mitigation measures for lines under operation; Demonstrate the effectiveness of a new HSL design, which includes protection measures for birds. This design is based on the concept of equally spaced tubular screens (PTE) Improve knowledge about the interaction between railway infrastructure and birds, with the aim of safeguarding biodiversity; Reduce the impact of existing and proposed HSL in the project area and on established bird populations in protected areas. Expected results: A section in the Spanish HSL network selected as a test site for a new anti-bird screen prototype; In situ study over a complete biological period of the impact of HSL on birds; The design and construction of a new type of anti bird strike screen based on PTE, with its effectiveness measured at a section of HSL;