Owl Studies at Ann Arbor, Michigan

TH• main purpose of this study was to determine the economic status of five species of owls found in the vicinity of Ann Arbor, Michigan.It considers their behavior when flushed, their food and feeding habits, their distribution by cover types and the distinguishing characteristics of their respective pellets and the effects of weathering upon these.The methods employed in this investigation have varied but little for the different species.The period of study extended from September, 1932, to May, 1933.An attempt was made to locate all of the individual owls in the region studied.DESCRIPTION OF THE AREA The country along the Huron River valley is flat to rolling.It was originally covered with hardwoods, and deciduous woodland tracts still extend intermittently for miles, bordered here and there by farm land.These wooded areas consist of second-growth hardwoods most of them from forty to sixty years old and others up to one hundred years old or older.Some of the common species are: pignut and shagbark hickory, swamp white oak, red oak, white oak, bur oak and American elm.The majority of such trees yield seed and nut crops which help support a considerable rodent population, most numerous of which are the meadow mice and deer mice.Although few evergreens are indigenous to southern Michigan (red cedar, ground juniper, black spruce) approximately three hundred acres have been planted to conifers within the area covered by this investigafon.These plantations consist mainly of white pine and red pine with occasionally Scotch pine and Norway spruce.They vary in height from ten to fifty feet and in age from ten to twenty-five years.Wooded areas farther from the river are in scattered blocks of from five to ten acres.The ages here are about the same as those in the river-bottom hardwoods; the older stands occupy about one-fifth of the total area and are generally located w•thln moist or semi-swamp sites where the American elm and black ash predominate.The forty to sLxty age-class stands are on well-dralned soils and consist for the most part of oak and hickory.Marsh and agricultural lands border the wooded areas.LONG-EARm) OWL (Asio wilsonianus) Long-eared 0wls were found in two distinct habitats.During the late summer, fall and winter months they inhabited the coniferous woods and during their nesting and brooding seasons from March until June, they were found in the hardwoods.