peer reviewed ; In some areas of Western Europe, red-backed shrike populations, following a strong decline in the third quarter of the 20th century, were re-established in recent decades. Variations in climate seem to have played a crucial part in this striking evolution by modulating the species breeding success. In order to test this hypothesis, the annual fluctuations of several of these populations in south-eastern Belgium were compared with the variations in a series of climatic factors. This study derives from a number of censuses, completed during the breeding period between 1979 and 2008, and the data from the weather stations closest to the populations studied. The modelling of climate influence on annual population fluctuations is based on a Partial Least Squares regression (PLS), following the classification of variables using a latent variable approach. From 1980 to 2008, for the April-August period, the mean minimum temperature tended to rise. During these five months, rainfall intensity reached a minimum in the 1990’s and increased significantly thereafter. During the three last decades, rainfall intensity for June tended to decrease whereas that for August increased. The annual variations of these monthly averages were very high. As for breeding population fluctuations, our results highlighted the significant role of various parameters related to minimum temperature and pluviometry during the breeding period. Spring and cold wet summer periods seem to have a significant negative impact on the rate of breeder recruitment. These results suggest that the breeding success of red-backed shrike can benefit from global climate change due to the higher success rate of broods. This however applies provided that its habitat is preserved – in terms of quality and surface area – and that this warming does not generate overly high rainfall during a critical period of its breeding cycle. The importance of climatic factors in population fluctuations for this shrike provides opportunities for further ...