‘HE COWBIRD. 29 
stomachs, which shows that the birds relish them. Knotweed, smart- 
weed, and other species of the genus Polygonum, all noted weeds, were 
found in 49 stomachs. The other items of the weed-seed food are eaten 
to a greater or less extent, but not by so many birds as are those 
specifically mentioned. Of the 544 stomachs only 2 were filled with 
grain alone, while 94 contained nothing but weed seed. The amount 
of weed seed destroyed by birds in a single year in the United States 
isimmense, and it is evident that the cowbird is one of the noteworthy 
agents by which the already overflowing tide of noxious weeds is kept 
within its present limits. 
SUMMARY. 
In summing up the results of the investigation, the following points 
may be considered as fairly established: (1) Twenty per cent of the 
cowbirds’ food consists of insects, which are either harmful or annoy- 
ing. (2) Sixteen per cent is grain, the consumption of which may 
be considered a loss, though it is practically certain that half of this 
is waste. (3) More than 50 per cent consists of the seeds of noxious 
weeds, whose destruction is a positive benefit to the farmer. (4) Fruit 
is practically not eaten. 
The following table shows the percentage of each of the principal] 
kinds of food for every month in the year: 
Food of the cowbird. 
[NUMBER OF STOMACHS EXAMINED: January,3: February,10; March, 18; April, 83; May, 99; June, 53; 
July,57; August, 38; September, 79; October, 70; November, 23; December, 11. Total, 544.] 
5 B g s 
cs re re a a B= | SS g 
Food. g Se | ast é % ga | 2 E = be 
| q 2 m E g 2 2 O Q 3 a 
ape ok oe ge eo ae gee comma 
o> i] 
f@le/sei/<¢4)/se2!16)/5 14/8 |}oé/)/2e4/]4) « 
ANIMAL, Per- | Per- | Per-| Per-| Per-| Per- | Per-| Per- | Per- | Per- | Per- | Per-| Per- 
Predaceous bee- 
Te veccccntrc nea meceudluvemaslyaoase HP |) BE9e) 164), 19S 2. ohewcedeleeeenel a ghee 0.4] 0.7 
Other beetles..... 0.3] 24] 24/10.2/123/165] 81] 1.7] 08] 02 )1Tr. |... 4.6 
Grasshoppers 2.9 | 5.8] 10.7 | 20.3 | 29.7] 45.1] 94] 1.8] 62 ]...-.. 11.0 
Caterpillars .. 24 | Bros dors: |) Sesh Bear 058d Ons) | Bes teaser ewes 28 
Other insects 1.0} O78) 204) 9:8) 722) Qab | 202) Dr, Olan) Os84 258 
Spiders and myr- 
1spods.. cccssceeloscce 0:23) sce 2.5] 22] 4.8] 29] 0.9] 0.3] 2Tr. |......).222.. ca 
Otheranimal food|......|...... O2 |). Od: | v9 | OESHl 0-5 || HOsd TE, [ese eel secsenceeess 0.4 
Total animal 
food ........ 2.3] 4.5] 8.6] 25.7 | 42.7] 59.1] 51.9 | 50.5] 18.0] 1.9] 6.3] 0.7 | 22.3 
VEGETABLE, 
Grains sesseecers BOER crs 31.3, 7.1 | 15.7] 12.9 | 27.2} 81.7] 289); LI} 61) 25] 16.5 
Weed seeds....... 64.4 | 95.5 | 49.1 | 66.1 | 41.5 | 28.0 | 19.2 | 16.6 | 58.1 | 97.0 | 87.6 | 96.8 | 60.0 
Other vegetable 
TOO occu seaskt asus |tanees F450:)|' Dal) OM ene TA | LD Neaese cl eesalaseses eens 1.2 
Total vegeta- 
ble food ....| 97.7 | 95.5 | 91.4 | 74.3 | 57.8 | 40.9 | 48.1 | 49.5 | 87.0 | 98.1 | 93.7 | 99.3 | 77.7 
1Tr, = trace. 
