Modeling the demography of species providing extended parental care: A capture-recapture approach with a case study on Polar Bears (Ursus maritimus)

Polar bears were caught and individually marked as part of a long-term monitoring program on the ecology of polar bears in the Barents Sea region (Derocher 2005). All bears one year or older were immobilized by remote injection of a dart (Palmer Cap-Chur Equipment, Douglasville, GA, USA) with the drug Zoletil® (Virbac, Carros, France) (Stirling et al. 1989). The dart was fired from a small helicopter (Eurocopter 350 B2 or B3), usually from a distance of about 4 to 10 meters. Cubs of the year were immobilized by injection with a syringe. Cubs and yearlings were highly dependent on their mother; therefore, they remained in her vicinity and were captured together with their mother. The file "CR.txt" contains the capture-histories of n= 158 family units captured between 1992 to 2019 arranged in a matrix with the status of each family unit (in rows) provided each year (in columns). Code 1 is for two-year-old independent juvenile female, code 2 is three-year-old independent juvenile female, code 3 is four-year-old subadult female, code 4 is four-year-old subadult female, code 5 is adult female with one cub, code 6 is adult female with two cubs, code 7 is adult female with one yearling, code 8 is adult female with two yearlings, code 9 is adult female with one depdendent two-year-old bear, code 10 is adult female with two dependent two-year-old bears, code 11 is adult female without dependent offspring, code 0 means a no-capture event. The file "captureday.txt" contains the date of capture, in day of the year, for each family unit (in row) each year (in column). "NA" means a no-capture event. The file "weaning.txt" contains the status (code 1 is independent from its mother, code 0 means still dependent from its mother), identification number and date of capture of each two-year-old bear (n=120 males and females) captured on the field.