Background The lesser kestrel (Falco naumanni) is a member of the hawk family. It is usually found in steppic and semi-desert areas or among the irrigated crops and low scrub of hot or temperate zones. It is a migratory bird: breeding occurs in southern Europe and extends as far east as Asia Minor and as far south as northern Africa. From the 1960s to the mid-1990s the population throughout Europe fell dramatically. Now a gradual recovery is underway and the population is currently estimated at 20,000 pairs, 40% of which can be found in Spain. The four SPAs covered by the LIFE project in Aragon's Monegros region hold 295 breeding pairs – an important concentration of the Iberian population. The threats facing the species in this territory include the loss of buildings that were traditionally used as nesting sites (farms and country houses), changes to feeding areas, increased presence of rats, cats and foxes that compete for its prey, contamination by pesticides and lack of awareness on the part of the local population. Objectives This project aimed to conserve Aragon's lesser kestrel population by protecting its nesting habitats in the Monegros SPAs, maintaining and improving its reproduction rate and increasing the distribution of the species to areas with little likelihood of change. The main activities planned included the repair of traditional rural houses, population monitoring, predator control, analysis of biological samples of individuals to determine contamination levels and identify the causes of reproductive failures. An information campaign principally targeting the local population was also planned. Results The implementation of the conservation plan for lesser kestrel in Aragón through the project largely contributed to the steep rise in numbers recorded during the reference period of the project (1999 - 2004) in this northern Spanish region. The species population has increased by 75% (from 589 to 1041 breeding pairs); the usual breeding locations have consolidated and the number of colonies and their densities has also increased in the region and in the project area of Monegros county in particular. The expansion of the population towards the neighbouring regions of Navarra and La Rioja across the Ebro River valley and towards the lower Aragón localities has been confirmed. The direct actions of the conservation plan were also enhanced by indirect habitat conservation measures derived from the binding nature of this plan through regional Decree 109/2000. Under the decree, development projects that affect the species range are appraised by the Species Conservation Services of the regional government. Development projects could then be legally bound to take into account conservation needs. Another key result was the refurbishment of 50 old agricultural buildings as breeding habitat for the species in order to consolidate breeding colonies. Such restoration worked served to raise awareness of the need for conservation among the local population. Educational kits were produced and distributed to all schools in the project scope. The approach to control predation, however, was redefined during the project. While predators remain a key threat upon the species, the project shifted focus from rats (which were believed to be the main predator at the beginning of the project) to mid-size mammals such as foxes and stone martens that predate on colonies settled in restored buildings in particular.