MICHIGAN ACADEMY OP SCIENCE. 
151 
TWENTY-FIVE YEARS OF BIRD MIGRATION AT ANN ARBOR, 
MICHIGAN. 
NORMAN A. WOOD. 
(From the University Museum, University of Michigan.) 
The following first-arrival records of the spring migration were made 
in the vicinity of Ann Arbor, Michigan, during the past 25 years. 
With few exceptions these records have been taken in the area included 
within the Ann Arbor topographic sheet of the U. S. Geological Survey. 
This area has been described by Transeau (Bot. Gaz., Vol. XL, pp. 351- 
356), and from which the following account is taken: “There are, then, 
three natural divisions of the Huron drainage basin: (1) the loose- 
textured rough interlobate moraine; (2) the clay morainic belt lying 
to the southeast of it; (3) and the low-lying plain extending to Lake 
Erie. Each implies important differences in the way of bog formation 
and provides “edaphic factors which determine to a large extent the 
nature of the dominant forest covering.” These divisions have a 
marked influence upon the bird life. The first division is com¬ 
posed of “morainic knobs, lake basins, abandoned glacial drainage chan¬ 
nels, and sand plains.” This area extends down the Huron river to just 
below Portage lake. Its characteristic forest is composed of certain 
oaks, associated northward with some pine and many groves of tam¬ 
arack. “These tamarack areas are to be seen on all sides in the region 
of the interlobate moraine; they are quite common in the clay morainic 
belt, but are practically wanting on the lake plain.” The second divi¬ 
sion, the clay morainic belt, extends obliquely northeast and southwest 
nearly parallel to the first and reaches along the Huron river from 
near Portage lake to Ypsilanti, nine miles southeast of Ann Arbor. 
Most of my early records were made near Saline, Mich., which is near 
to a broad glacial valley extending south and west from Ann Arbor to 
Adrian. This channel is apparently today a migration route, and a 
breeding place for a number of species which seem to be extending their 
range northward. It is here that many of the records of the more south¬ 
ern species have been made, such as the Yellow-breasted Chat; Hens- 
low’s, Leconte’s and Lark Sparrows; Swallow-tailed Kite, and also the 
Turkey Vulture which has been found breeding near Macon. Many 
records have been made about three miles east of Ann Arbor on the 
Huron river at what is locally known as the “Overflow.” This is a Ioav 
swamp area nearly covered by the back waters from a dam built at 
Geddes. This region affords a variety of conditions and is a very favor¬ 
able one for the study of many species. This spot has been quite thor¬ 
oughly worked for many years and has afforded many rare records for 
the vicinity. 
The third division—the lake plain areg—extends from Ypsilanti east¬ 
ward, and is a glacial lake plain gently sloping southeastward from 
the morainic belt just described, to the western shore of Lake Erie. 
