Porcupine (Erethizon dorsatum) demography in central Massachusetts
Journal or Book Title
CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE
From 1991 to 1993 we radio-collared and monitored 50 porcupines (Erethizon dorsatum) in central Massachusetts to obtain estimates of survival and reproduction, and applied these estimates to a model of porcupine population dynamics to estimate the annual rate of change (λ). The annual survival rate for all adult (> 1 year old) porcupines was 0.67 ± 0.07 (mean ± SE). Survival was higher, but not significantly so (P = 0.22), for adult females (0.74 ± 0.08) than for adult males (0.56 ± 0.12). Adult porcupines died of starvation (annual mortality rate 0.08), injuries (0.05), interactions with humans (0.04), and disease (0.05) but not predation. Annual survival of juveniles (< 1 year old) ranged from at least 0.37 in 1992 to at most 0.39 in 1993. Minimum birth rates of radio-collared females > 2 years old, determined by sightings of young near females, lactation, and pregnancy status as determined by ultrasound, were 0.64 in 1992 and 0.62 in 1993. Incorporation of maximum and minimum values of demographic parameters from this study and from the literature into population models indicated a decreasing porcupine population.
Hale, MB and Fuller, TK, "Porcupine (Erethizon dorsatum) demography in central Massachusetts" (1996). CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE. 125.