20 THE CONDOR Vol. XXII 
breast, with a few from the back. In a few birds taken during the season of molt 
in August and September, a few primary feathers from the wing were found, 
but this was unusual. 
In field observation the writer frequently has watched Eared Grebes and 
others preening and dressing the plumage. The body covering of feathers in these 
birds is dense and heavy, and many feathers are loosened during their active 
movements. Feathers that came out during preening were occasionally disearded, 
but more often were dabbled in the water until well moistened and then were 
swallowed. Occasionally during the breeding season when EKared Grebes were 
in pairs, feathers discarded by one bird were seized and swallowed by its mate. 
Parent birds apparently feed feathers to the young as soon as they are large 
enough to take the food of adults, as fully formed contour feathers were found 
in the stomachs of young that were still covered with down. It is possible that 
these young birds picked up floating feathers of their own volition, but it seems 
more probable that they received them from their parents. These are the only 
cases in which grebes seemed to eat feathers that were not taken from their own 
bodies. 
After feeding, grebes begin the care of their plumage. The feathers that 
come out during this process are swallowed and serve to keep the stomach com- 
fortably full as the food elements are prepared and passed on into the intes- 
tine. The feathers swallowed are ground up and eventually enter the intestine, 
though a plug of them remains in the pyloric lobe. These seem to represent the 
feathers remaining from the preceding meal as they are often more broken than 
the feathers taken with the food that fills the ventriculus at the time. Thus the 
plug in the pylorus seemingly is renewed with the digestion of each mass of food. 
There is evidence to show that when food is abundant grebes feed only once each 
day, and the feathered plug would therefore be changed once daily. 
In the American Anhinga (Anhinga anhinga), a fish-eating bird, there is 
also a pyloric lobe developed in the stomach. This chamber is better separated 
from the stomach proper than in the grebes and has an additional peculiarity in 
the development of many very slender, corneous filaments that project as 
a brush from the surface around the pyloric opening. These point toward the 
main cavity of the stomach and are thought to act as strainers that prevent the 
passage of bones and scales into the intestine until they have been properly di- 
gested. With this structure in mind it may be suggested that the feathers filling 
the pyloric cavity in grebes have a similar function. During digestion this plug 
serves as a strainer that permits the passage of smaller food particles but catches 
the larger bones and scales of fishes, and the larger chitinous fragments of erus- 
taceans and insects. The plug is probably disintegrated rapidly, but its place is 
taken immediately by other feathers that have been eaten meanwhile. The habit 
would seem to be developed mainly in connection with a diet of fish. It was 
noted that in the Eared Grebe, a species that feeds extensively upon soft-bodied 
insects and crustacea and takes few fishes, feather remains often were small in 
quantity, and at times were wanting entirely. Occasionally, in the cases of the 
Pied-billed and Holboell grebes, the stomach was filled with a mass of feathers 
with no food remains present. It is possible that these individuals had had dif- 
fieulty in securing prey but had continued the feather eating habit to aid in sat- 
isfying the cravings of hunger. 
Washington, D. C., October 27, 1919. 
