Juvenile and adult mortality patterns in a vicuña (Vicugna vicugna) population

Abstract

Abstract Neotropical ungulates are poorly understood with regard to age-specific mortality and how it relates to different mortality causes. During January 2008–April 2011, we investigated mortality patterns of calf (<1 year old) and adult vicunas (Vicugna vicugna) in west-central Argentina. Specifically, we analyzed whether birth mass, birth date, and sex of radiomarked vicuna calves affected 1st-year survival; quantified cause of death for marked calves and unmarked adults; and explored how primary productivity and quality of forage and diet related to body condition of adult vicuna carcasses. Birth mass was a strong predictor of 1st-year survival: a 1-kg (∼18%) increase in birth mass resulted in a 54% decline in the risk of death. Further, low survival rate in 1 calendar year was associated with low mean birth mass during that year, but not with population density and forage quality in the previous year. Puma (Puma concolor) predation accounted for ≥49% (n = 93) and 91% (n = 89) of the mortality in cal...