22 BULLETIN 1196, U. S. DEPARTMENT OF AGRICULTURE. 
horned or eared grebes, and only occasionally is there evidence that 
it resorts to dead insects floating on the water as a source of food. 
The crawling water-beetles seem too small to attract much attention 
from this bird, as they were encountered only 5 times. Adult pre- 
dacious diving beetles were favored in this group, especially those 
species of moderate or large size. The larvae of these beetles were 
encountered in only one instance, but adults of various forms were 
identified no fewer than 76 times: 
The active whirligig beetles (Gyrinidae) also figure to a some- 
what surprising degree in the food, being identified 16 times. These 
are probably secured by diving, as they seem less erratic in their 
movements when submerged than when on the surface. Water 
scavenger-beetles (Hydrophilidae) were less favored, occurring only 
13 times. The enumeration above is in striking contrast with that 
in the case of the horned and eared grebes, where Hydrophilidae 
and miscellaneous beetles, secured when dead, figured so prominently. 
In the case of the present species beetles other than aquatic were 
taken rarely, as is shown in Table 3, following this section. 
Remains of dragonflies and damselflies amount to 8 per cent and 
were eaten during the warmer months from May to October, in- 
clusive. In July and August these insects form a considerable part 
of the food, as in 19 stomachs representing these two months their 
remains amount to 34 per cent. The greater part were nymphs of 
dragonflies, as damselflies figured in the food of only one bird. 
Miscellaneous insects of other groups amounted to 2.3 per cent. 
They were made up of remains of grasshoppers and caterpillars in one 
instance, the puparia and larvae of flies in three, and some miscella- 
neous fragments of Hymenoptera. The dipterous remains are those 
of aquatic species easily obtained by a diving bird. The others 
may well have been floating about on the water, where they were 
picked up at random. 
Other miscellaneous animals of a variety of forms, but not eaten 
frequently, amounted to 2.1 per cent. Spiders were taken 3 times, 
marsh snails (Physa and Limnaea) once, other aquatic snails not 
certainly identified 3 times, and small frogs 5 times. 
SUMMARY. 
Though nearly one-fourth of the food of the pied-billed grebe is 
made up of fishes, the majority of those taken belong to species of 
slight economic importance. Those of value are compensated for by 
the large number of crawfishes destroyed, as in bulk these amount to 
more than the fishes taken. Aquatic Heteroptera and Coleoptera also 
are favored and together comprise one-third of the diet. Predacious 
species in both groups are well represented, some of them being of 
sufficient size to prey upon fish fry. In eating these, therefore, the 
grebe more than compensates for the fishes consumed. 
Complaint is made of pied-billed grebes around fish hatcheries. 
There they may do considerable harm, though the evidence at hand 
shows that even in such localities they seem to take many water 
bugs and crawfishes, all of injurious habits. Grebes, however, will 
not confine their attention to this kind of food, and when they appear 
on the ponds and it is not possible to drive them away they should 
