Biology of the Eastern Chipmunk, Tamias striatus: Life Tables, Age Distributions, and Trends in Population Numbers
1973; Oxford University Press; Volume: 54; Issue: 1 Linguagem: Inglês
10.2307/1378877
ISSN1545-1542
Autores Tópico(s)Animal Ecology and Behavior Studies
ResumoPopulations of the eastern chipmunk (Tamias striatus) were studied during the years 1962 to 1970 at locations in Pennsylvania and Vermont by means of repetitive live-trapping of gridded plots. Analysis of the resultant data provided life tables, survivorship curves, and population age classes for this species. Calculations were based on disappearance of individuals from the trapped plots rather than on known mortality. Four thousand individuals were trapped of which 1580 were first captured as juveniles. Survival tended to be constant over much of the adult life span but differed among populations at different localities and between sexes. Season of birth also affected survival rate. Yearly survival rates based on a composite series of known-age chipmunks varied from 0.34 to 0,64 with an average of 0.43. Mean life expectancy at first capture ranged from 1.0 to 2.25 years with a mean of 1.29 years. There is a shift in age distribution from year to year as a result of different numbers of juveniles entering the population in each breeding season. Fluctuations in the numbers of chipmunks handled over the period of the study indicated the possibility of a cycle of 3 to 4 years. There also appeared to be synchrony in these fluctuations between the populations in Pennsylvania and those in Vermont.
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