Explanation:

These data were obtained as part of a field study of social behavior of the prairie vole, Microtus ochrogaster in alfalfa fields (LF 2 and ALF 3) that was also used in the 25-year research. During this study we monitored all nests twice weekly for 63 months, with very few skips of scheduled trapping (mostly during vacation periods and when had to attend meetings—weather did not cause stoppage of trapping except for a very few days). We reformatted the social behavior data into a format for demographic analyses. These data essentially monitor a population every 3.5 days for 63 months.

The population in ALF 2 was monitored twice weekly from March 1982-July 1984. That in ALF 3 was monitored from Oct 1983-May 1987.

The entry columns for these data files are as follow (see also methods):
A. The original floppy disc on which the data were originally entered; ignore.
B. Trapping session here indicates the sequential months of the study; can be used to sort by month by year; otherwise of no interest.
C. First day of the trapping of a given Mon-Tue and Thu-Fri session. Note that normally during each month, there are two dates that are only one day apart. The second date is the beginning date of the grid trapping that was conducted each month. In actuality, the mid point of this session is about 3.5 days from the former and 4 days until the next behavior trapping session. So, simply using the date as a 3.5 interval between “sessions” gives the correct interval.
D. Month; obvious,
E. Year; obvious
F. Animal number; obvious
G. Sex; obvious
H. Reproductive condition: for these entries, non reproductive is entered as 0; reproductively active (males, tested scrotal; females, vulva open, lactating, or pregnant) entered as 1; some reproductive entries are recorded as 2; not certain why the enterer did so, but simply consider them as reproductive.
I. Wt, body mass; obvious; note that, except for the last year, body mass was recorded only at first capture and during the monthly grid trapping; during the last year body mass was recorded at almost all captures.
J. New or recaptured previously; ignore this column; entries not consistent or accurate.

3.5-data set publications:

l990. The effects of predation of snakes on social organization of the prairie vole, Microtus ochrogaster. Amer. Midl. Nat., 123:365-371, (L. Getz, N. Solomon, T. Pizzuto).

1997. Factors affecting life expectancy of the prairie vole, Microtus ochrogaster. Oikos, 80:362-370. (L. Getz, L. Simms, B. McGuire, and M. Snarski

2000 Nestling survival and population cycles in the prairie vole, Microtus ochrogaster. Canadian Journal of Zoology 78: 1723-1731. (L. Getz, L. Simms and B. McGuire)

2004. Demography of fluctuating populations: temporal and phase-related changes in vital rates of Microtus ochrogaster. Journal of Animal Ecology. In Press (A. Ozgul, L. Getz and M. Oli)

2004. Delayed density-dependent effects and population fluctuations in the prairie vole, Microtus ochrogaster. Acta Zoologica Sinica. In Press. (L. Getz, L. Simms, J. Hofmann, and B. McGuire)