NORTH AMERICAN GREBES. Ly 
aquatic mite, and a snail (Planorbis); remains of a marine worm 
(Nereis) and of a frog; and, representing the group of crustaceans, 
an amphipod (Gammarus), an opossum shrimp (Veomysis), and 
2 unidentified forms. | 
In the field the writer has observed eared grebes swimming about 
in pursuit of alkali flies (Kphydridae) that rested lightly on the 
surface film of the water. As they came within reach they were 
seized with an almost unerring thrust of the bill. On Lake Burford, 
northern New Mexico, at dusk the birds gather in flocks on a broad 
open expanse to secure the ants and beetles, which, flying out from 
the sage-grown hills surrounding the lake, are entrapped and drowned 
in the water. Gnats (Chironomidae) and Mayflies that emerge in 
myriads from the water also furnish an eagerly sought supply of 
food. Insects drifting in the water form a favorite source of sub- 
sistence with these birds and are often intermingled with living prey. 
The tireless activity of these grebes in feeding is shown by the 
stomach contents of one bird secured in Montana at the end of May. 
This one individual had eaten 315 weevils (//yperodes), 650 water 
scavenger-beetles of one genus (Berosus) and 52 belonging to three 
or more other genera, 42 leaf beetles (A/yochrous squamosus), 2 
billbugs (Sphenophorus), 3 rove beetles, 6 ground beetles with two 
larvae belonging to the same family, 61 caterpillars, 1 bug, 2 centi- 
pedes, and 3 or more spiders, a total of at least 1,139 individuals. 
SUMMARY. 
From this detailed enumeration of the food of the eared grebe 
it appears that the species is harmless to human interests. The 
fishes taken are few in number and apparently of little or no eco- 
nomic value. Insects form a greater proportion of the food than 
in the three preceding species, but have little economic significance. 
A considerable number of dragonfly nymphs are eaten, but these 
are destructive of small fishes, though adult dragonflies are valuabie 
as enemies of mosquitoes. Like the horned grebe, the present species 
picks up many dead insects that are drifting about on the surface 
of the water. Like its larger cousin, the western grebe, this grebe 
was formerly killed in large numbers for its plumage, but fortunately 
laws and fashions changed in time to prevent its extermination. 
There is no longer danger of a recurrence of this slaughter, as the 
killing of the eared grebe is now prohibited by law, a protection that 
2 ee merited on account of the bird’s harmlessness in its choice 
of food. 
TABLE 2-—Items of animal food identified in stomachs of the eared grebe, 
with the number of times that each occurred. . 
ANNULATA (Worms). ZYGOPTERA (Damselflies). 
_ EDU pg 2 ae eee eae 1 | Unidentified damselflies _____._._______ 1 
AMPHIPODA (Shrimplets). ANISOPTERA (Dragonflies). 
ERLE TAG) | ee ee eee oe ees 1 | Libellulid nymph___ ee a a 
Unidentified nymph_________ eS 1 
ScHIzZOPODA (Opossum Shrimps). 
ORTHOPTERA (Grasshoppers, etc.). 
BTS A) 2 aS eens eae 
Unidentified crustaceans____-_-______ 2 | Unidentified grasshopper________~ a 1 
