Mild weather in winter does not lead to enhanced physiological state of great tits in a northern city.

W.csv - Dataset with weather data archive https://rp5.ru for a meteorological station situated at 59°58' N, 30°17' E (the closest to the study site)temp - Air temperature at 2 m height (°C)press - Atmospheric pressure (mm Hg)hum - Relative humidity (%)dir - Wind direction vel - Wind speed (m/s)prec - Precipitation accumulation Season - Winter season Phys.csv - Dataset with physiological status parameters of great tits (Parus major) across four winter seasons.Status - Bird capture status (new/recapture)Order - Order numberR_ser - Bird ring seriesR_num - Bird ring numberDate - Capture date Year - Calendar yearMonth - Numeric month (1-12)Time - Capture time (HH:MM)Seas_no - Winter season identifier (1-4)Time_SR - Time since sunrise (min)Species - Parus majorNet_num - Mist net IDSex - male/femaleAge - Age class (JUV/AD)Wing - Wing length (mm)Fat - Subcutaneous fat score (0-8 scale)Muscle - Pectoral muscle profile score (0-3)Weight - Body mass (g)CI - Condition index (mass/wing ratio)Sample - Blood sample IDHem - Hematocrit (%)Time_A_dec - Time from capture to blood samplingglu - Blood glucose (mmol/L)buty - β-hydroxybutyrate (mmol/L)glu_CV - Glucose coefficient of variation (%)buty_CV - β-HB coefficient of variation (%)glu_sd - Glucose standard deviationbuty_sd - β-HB standard deviationhet - Heterophil count lym - Lymphocyte count leuk_t - Total leukocytes eryt - Erythrocytes (RBC)hl - Heterophil-to-lymphocyte ratio (HL ratio)wbc - White blood cells to 10000 RBCparasit - Hemoparasite presence (0/1)observ - Observer initialshem_dec - Hematocrit decimallog_hl - Log-transformed HL ratioFinal_analysis.r - this file contains the R script for the statistical analysis