4 THE OA UD U BO No 5 Oe 
boxes and den boxes has been confined to a prairie region where the experi- 
mental use of large nest boxes has been extended to an area of very inten- 
sive farming in the center of the [Illinois corn belt. Here natural tree 
cavities are very rare or entirely lacking. On the Urbana Township Wildlife 
Restoration Area in Champaign County where a Pittman-Robertson Project 
has been set up for research studies, 56 nest boxes were installed in fence- 
row trees, osage hedges, and small farm woodlots during November, 19389. 
Female screech owl incubating eggs in a nest box on the 
experimental area in Champaign County. 
These boxes were patterned after the wood duck boxes but were designed 
with larger openings and deeper cavities to accommodate such species as 
opossum, raccoon, and fox squirrel. Constructed of rough cypress lumber, 
these boxes are three feet deep and ten inches square inside.* The tops are 
removable so that the contents may be examined at any time. Dry leaves 
were placed in the bottoms of some of the boxes, while others were lined 
with fine dry bluegrass. At the time they were installed no one knew exactly 
what part they would play in benefiting the bird and mammal species that 
were present on the area. The results have been interesting and have 
extended beyond our early expectations. 
Screech owls began using the boxes within three days. They have been 
among the most abundant and constant users of these box cavities. The 
boxes used by these little owls have yielded valuable data on the food and 
nesting habits of this species. About the time of hatching, the male owl 
carries in a surplus food supply. In one instance five freshly killed house 
mice were found stored neatly in one corner of a box in which the last of a 
clutch of five owl eggs had just been hatched. In another box at the time of 
*Blueprint plans for building den boxes are available from the Illinois State Natural 
History Survey, Urbana, Illinois. 
