74 Grundtvig—On the Birds of SMocton, Wisconsin. 
gion explored by me includes an area of only twelve square 
miles, and the conditions there are not so diverse that I can 
by any means suppose that all the birds that belong to Outa¬ 
gamie county can be found there. Neither are my observations 
equally satisfactory as regards all the species found there. I 
can not deny that here and there a species has escaped my at¬ 
tention and I know that I have seen several that I had no op¬ 
portunity to determine. This is especially true of birds of 
prey and water birds. As to the former my observations are 
very fragmentary. Most of them are seen only in migration 
time, are very difficult to shoot, and difficult to identify in 
flight. Many more than I give certainly breed in the region, 
but I was too much occupied in other investigations to search 
after their nests. I hoped in a third year to complete my ob¬ 
servations as far as possible, but circumstances forbade. I 
have taken great pains to procure exact information as to the 
spring migration of some of the smaller birds, especially the 
warblers (, Sylvicolidce ). But it must be remarked that the ob¬ 
servations were in a high degree difficult after the woods had 
leafed out. Should any species of these birds have escaped my 
attention they must certainly be among those that migrate 
latest. The difficulty of studying birds in tall leafy trees is 
also the principal reason why I cannot give more information 
about the fall migration. I saw many of the birds again in the 
autumn, but I seldom note it, since to my mind such scattered 
observations are of no value. 
Even exact observations of migratory birds at a single sta¬ 
tion have, on the whole, only little importance in any case 
when the spot is not in some way especially favored as a stop¬ 
ping point in migration. I supposed I had found on the penin¬ 
sula in the river an especial stopping point for warblers and birds 
that accompany them,vireos and certain flycatchers ( Tyrannidce ). 
That they have such stopping points I doubt not. I have 
noticed that many other birds (such as Turdus aonalaschhoe 
pallasii , Zonotrichia albicollis , Passerella iliaca , waders, and 
ducks) can be invariably found during migration at certain fixed 
places. I have since learned however, that the warblers probably 
have their stopping point on the heights south of the railway. 
