This dataset includes two files; one titled “FirstMidLast” includes data for all nestlings, with each “row” of data corresponding to an individual nestling (identified by their band-number (“BandNum”)). The other file (“Broods”) includes brood-level data and data regarding maternal body condition. These data were collected by E. Keith Bowers (keith_bowers@hotmail.com). Column headings (i.e., variable names) are described as follows: Brood: Brood number; gives a number to specify a brood for use as a random effect in SAS Nest: Nestbox - nest number; (e.g., "Z 11-1" represents nestbox Z 11, and "-1" indicates that nest was the first one built in box Z 11 this season) E1D: Egg-1-date; the day of year (date number) on which the first egg of the clutch is laid BD0: Brood-day zero; the day of year (date number) on which hatching begins Synchrony: Degree of hatching synchrony (i.e., synchronous or asynchronous) ClutchSize: Number of eggs produced by the female NYBD11: Number of Young present in the nest on brood-day 11 (11 days after BD0) Egg: Egg-number, or an egg's position in the laying sequence Egg_position: An egg's position relative to others within the clutch; 1 = "first", 2 = "early", 3 = "middle", 4 = "late", 5 = "last" Sex: The sex of an individual (0 = female, 1 = male) HatchOrder: Order in which nestlings hatched from their eggs, or a nestling's position in the hatching sequence Hatch_position: A nestling's hatching position relative to others within the brood; 1 = "first", 2 = "early", 3 = "middle", 4 = "late", 5 = "last" MassBD4: The mass (g) of an individual nestling (row) on BD4, four days after the first egg of the clutch hatches MassBD11: The mass (g) of an individual nestling (row) on BD11, eleven days after the first egg of the clutch hatches Mass_diff: The mass (g) gained by an individual nestling from BD4 to BD11 TarsusBD11: The tarsus length (mm) of an individual nestling (row) on BD11, eleven days after the first egg of the clutch hatches HCTBD11: The hematocrit value (%) of an individual nestling (row) on BD11, eleven days after the first egg of the clutch hatches BandNum: An individual nestling's unique U.S.F.W.S. (United States Fish and Wildlife Service) band number Survival: Whether or not the hatchling survived to leave the nest (0 = no, 1 = yes) NFATE: Fate of the nest; A = successful, F = failed (numbers represent suspected causes of nest failure; e.g., predation or abandonment) TDAY: Term-date; the day of year (date number) on which the nestling period is completed, this may be caused by fledging of young or by nest-predation/failure Hatching_span: Approximate length of time (h) between hatching of the first and last eggs within a clutch FBAND: The unique U.S.F.W.S. band number of the female producing the nestlings MBAND: The unique U.S.F.W.S. band number of the attending male Hatching_Span: number of hours elapsed between the hatching of the first and last eggs within a clutch Fem_Mass: Mass (g) of the female, most-often captured during incubation, but occasionally after eggs have hatched Fem_Wing: Length (mm) of female's 1st primary feather Fem_Tail: Length (mm) of female's tail feather Fem_Tarsus: Length (mm) of female's tarsus (tarsometatarsus) Hour: Hour of day when female was weighed Pred_Fem_Mass: Predicted female mass from mass*tarsus linear regression output Resid_Fem_Mass: Residual female body mass from mass*tarsus linear regression output