416 
ward, birds from the south coming in more rapidly than winter resi- 
dents left for the north, until about the middle of April, at which time 
the crest of the wave had passed on, to be followed by a downward slope 
in its rear as the winter residents hastened their departure and dwin- 
dling numbers of the latest migrants and the summer residents came in. 
Brrps per Square MILE IN SuccEsstvE NortTH- 
ERN AND CENTRAL ILLINOIS TRIPS, 
Serine or 1907 
March 2 to 15, Northern Illinois 394 
March 19 to 21, Central Illinois 543 
March 29 to April 5, Central Illinois 790 
April 20 to May 29, Central Illinois 549 
The details of the migration movement can best be shown by taking 
up the separate trips in order, and dividing the eastern Illinois trip from 
north to south into three sections corresponding to our usual divisions 
of the state. So proceeding, we shall have two sets of data for northern 
Illinois, three for central, and one for southern, the areas covered in 
these sections being respectively 2215, 5055, and 588 acres. 
The most abundant species in northern Illinois at the time of the 
trip from Waukegan in Lake county to Scales Mound in Jo Daviess 
county (March 2-15) were the English sparrow, Lapland longspur, 
crow, prairie horned lark, and prairie hen, these together making up 
85 per cent. of the whole number of birds. This is essentially a winter 
list to which small numbers of tree sparrows, juncos, and both varieties 
of horned larks may be added, together with woodpeckers, nuthatches, 
and an occasional hawk. The spring migration was represented by a 
few meadowlarks, rusty blackbirds, bronzed grackles, red-headed wood- 
peckers, bluebirds, robins, and mourning doves and a single song sparrow. 
Tue Most AnuNDANT Birps (85 PER CENT. List), WAUKEGAN 
TO ScaLtes Mounp, Marcu 2 To 15, 1907 
Species No, of each | Ratio to total No. 
English sparrow 475 41.2 
Lapland longspur 188 16.3 
Crow 151 13.1 
Prairie horned lark 131 11.4 
Prairie hen 42 3.6 
All birds per square mile, 394. 
Of the 1107 birds recognized, 846, or 77 per cent., belonged to 
species classed as permanent residents, 218, or 19.7 per cent. were winter 
residents, 3.3 per cent. were summer residents, recently arrived from 
the south, and 5 (rusty blackbirds), or less than one-half per cent., 
were migrants. The spring infiltration thus amounted to less than four 
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