nce a female usually breeds more than once in the
course of a season. In any case, by autumn, when the actual field study
of woodrats was initiated, many houses were already deserted and in
disrepair. Although the rats were still moderately abundant, they were,
seemingly, much below the population peak of the preceding year.

Further drastic reduction of adults and subadults took place in the
winter of 1948-49. In the course of live-trapping operations from
mid-October into early December, 51 individuals were caught and marked.
Chiefly because of unfavorable weather conditions, field work was
discontinued in mid-December, and live-trapping was not resumed until
early March. Subsequently, only 12 of the woodrats previously marked
could be recaptured, and the population had become noticeably sparse.
Seemingly, more than three-fourths of the population present in late
autumn had been eliminated in the interval. In January, weather was
exceptionally severe; on the ninth and tenth the worst sleet storm in
twelve years occurred. Sleet fell in small granules, while the
temperature remained several degrees below freezing. Partial thawing on
January 12, 13 and 14 was followed by a steady drizzling rain on the
fifteenth. On the following day the temperature dropped to -7 deg.F. Ice
still remained from the sleet storm, and the slush again froze. On the
night of January 18, there was one of the worst snow storms on record
and temperature reached a low of 2 deg.F. Exceptionally low temperatures
persisted through January 24, with more sleet on January 25. Ice from
the earlier storm still remained. On January 30, the temperature dropped
to -7 deg. and a three-inch cover of snow still remained over the coat of
ice. The month of January, 1949, had the heaviest precipitation in 81
years (5.09 inches) and a cover of ice remained for at least 21 days.
There were other sleet storms of lesser proportions on February 2 and
again on February 21.

Ordinarily sleet would not seriously damage woodrats living in houses in
woodland habitats and less suitable hedge rows because it usually
freezes as it falls and coats only the surface of the house. Gradual
thawing would allow normal runoff without much penetration. Because the
sleet during the storm described above did not form a glaze as it fell,
the ice particles penetrated many houses. It has been observed many
times that captive woodrats refused food that was frozen or were unable
to eat it. Wo