186 BULLETIN OF WISCONSLN NATURAL HISTORY SOCIETY. VOL. 2. NO. 4. 
The work of Cooke, superintendent of the Mississippi Valley 
District, has broadened into several new fields of inquiry. In ad- 
dition to the report proper he has included original discussions 
upon ''The Relation of Migration to Barometric Pressure and 
Temperature" and "The Rate of Speed at which Birds Migrate." 
Although these new phases of the work were not undertaken un- 
til the period of investigation was nearly completed, and hence 
were merely experimental, the methods employed have opened 
several new fields to the students of migration (27). Mr. Wit- 
mer Stone followed Prof. Cooke's method of work on a less ex- 
tended basis and has presented us with a means of representing 
''bird waves" (28), graphically (29). 
Another entirely new department was brought into the method 
of observation in 1880, by Mr. W. E. D. Scott, who applied the 
telescope to the study of migration problems. This method, al- 
though of extreme importance, seems to have found little actual 
application. Beside the work of Messrs. Allen and Scott in 1881, 
and that of Mr. Frank Chapman in 1887, practically nothing was 
done until it was taken up by Dr. O. G. Libby of the University 
of Wisconsin in 1897. Since 1898 the telescope has been used 
for this purpose by Dr. Libby and the writer, at Madison, Wis- 
consin, each year up to the present time. During the spring of 
1900 a wider application of this method was obtained by asking 
a number of interested persons from our western universities to 
co-operate. These data together with all those that were taken 
at Madison will appear in the following report. 
The facilities for studying migration at light-houses have long 
been known. It was upon the suggestion of Prof. Newton in 
1880 that a systematic collecting of data from this source was 
first undertaken. Individual work at light-houses by experi- 
enced ornithologists has given us many valuable facts. Indeed 
the investigations of Herr Gatke on the Island of Heligoland 
(30), of Brewster at Point Leoreaux (31), and Chapman on 
Bartholdi Statue (32), should stimulate others to direct their ef- 
forts along these lines. 
27. Cooke, Rep. on Bird Migration in the Miss. Valley. Bull. No. 2, 
U. S. Dept. of Agr. 1888. 
28. A "bird loave'"' may be considered to consist of a very large number 
of individuals, of one or more species, which suddenly invade a certain? 
area." — (Cooke.) 
29. Auk, vol. 8, p. 194. 
30. Heligoland, An Ornithological Essay, 1895. 
31. Bull. Nutt. Ornith. Club, No. 1, 1886. 
32. P. S. M., vol. 45, p. 506. 
