.—Economical versus ecological development: a case study with white storks in a cattle farm. Aims: Wildlife and humans compete for natural resources generating conflicts that sometimes trans-late into financial loss. In this study, the economical costs of the upkeep of a white stork Ciconia ciconia colony at a cattle farm over a six-year period were evaluated. Furthermore, the effect of ash lopping in nest site selection and the efficacy of nest removal in controlling the population of this species was analysed. Location: The ash dehesa studied was located in the Northern area of the Madrid province, in both Soto del Real and Manzanares el Real localities (40º 44' N, 3º 49' E), from 1999 to 2004. Methods: Estimation was made of the economical cost of white stork colony maintenance by esti-mating the total weight of branches and bud shoots on the ashes. The tree type (lopped or unlopped) was noted to determine nest site selection where new nests were established in the subsequent year after lop-ping. Finally, it was recorded if removed nests (by the Regional Government as a method of population control) were less like to rebuilt in function of previous breeding success (failed or not). Results: Storks mainly selected lopped trees as nest sites. To avoid the increase of white stork pairs in the colony, lopping was not carried out in subsequent years, causing economical losses to landowners (a minimum of 13,902.33 in six years). In addition, due to the high nest-site fidelity in this species, the to-tal number of nests in the colony was not reduced by nest removal. Nests that contained a pair that failed in their reproductive attempt were less likely to be rebuilt in the consecutive breeding season. The results showed that selective nest removal (removal of nests which failed the previous year) might be a more ef-fective method for population control than nest removal methods used to date. Conclusions: Due to the low total economic cost of colony maintenance, it is proposed that econom-ical compensation by the regional government to the farm owners will be a more effective management measure than nest removal. Key words: ash, Ciconia ciconia, lopping, nest removal, nest-site fidelity, wild species on private property. RESUMEN.—Desarrollo económico o ecológico: estudio con cigüeñas blancas en una granja de ganado. Objetivos: La fauna salvaje y los humanos compiten por los recursos naturales generando conflictos que en algunos casos pueden traducirse en pérdidas económicas. En este estudio, se evalúan los costes económicos del mantenimiento de una colonia de cigüeña blanca Ciconia ciconia en una granja de gana-do durante un periodo de seis años. Además se analiza el efecto de la poda de los fresnos en la selección de los lugares de nidificación y la eficacia de la retirada de nidos como medida de control de la pobla-ción en esta especie.