All the data are included in 4 different files: 1) Allnests file includes all data collected per nest: the pair of plots (Pair), the plot (Plot), the ID of the nest (ID_Nest), the parasite infestation (Infestation: Control, Local or Foreign, i.e. the experimental treatment), the statut of the nest (Statut: if it was deserted (before hatching, dest), if young died before d14 (Dead) and if at least one young fledged (Fledged)), laying date (LD), Clutch size (CS, in eggs), number of unhatched eggs (Unhatchegg, in eggs), number of hatching (BS, in eggs), brood size at d2 - 1st visit (BS2), number of young fledged (FS), number of females fledged (SRfl), hatching date (HD), fledging date (FD), nestling period (Periodnest, in days), incubation date (ID), duration of incubation (Periodinc), number of adult fleas after fledging (adultfleas) 2) Allnestlings file includes all data collected by nestling and covariates for models: the pair of plots (Pair), the plot (Plot), the ID of the nest (ID_Nest), the ID of the nestling (ID_Ring), the parasite infestation (Infestation: Control, Local or Foreign, i.e. the experimental treatment), body mass at d2, d8 and d14 (Wd2,Wd8,Wd14, to the nearest 0.1g), length of tarsus (Tars, to the nearest 0.1 mm), length of the 8th primary wing feather (P8, mm), laying date (LD), Clutch size (CS, in eggs), sex of nestling (Sex, 1 = female), brood size at d14 - 3rd visit (BS14), fledged (Fl, fledged = 1, dead = 0), Recruit (Recru, recruit = 1, no recapture = 0) 3) subdata_tolerance file includes all data collected by nestling and covariates for models in order to test tolerance: the pair of plots (Pair), the plot (Plot), the ID of the nest (ID_Nest), the parasite infestation (Infestation: Control, Local or Foreign, i.e. the experimental treatment), the number of adult fleas (adultfleas), the ID of the nestling (ID_Ring), length of tarsus (Tars, to the nearest 0.1 mm), length of the 8th primary wing feather (P8, mm), body mass at d14 (Wd14, to the nearest 0.1g), laying date (LD), sex of nestling (Sex, 1 = female), brood size at d14 - 3rd visit (BS14) 4) Parents file includes all data collected for parents: the pair of plots (Pair), the plot (Plot), the ID of the nest (ID_Nest), the ID of the parent (ID_Ring), sex of parent (Sex, 1 = female), length of the wing (Wing, mm), length of tarsus (Tars,to the nearest 0.1 mm), body mass (Weight, to the nearest 0.1g), the parasite infestation (Infestation: Control, Local or Foreign, i.e. the experimental treatment)