80 BULLETIN 208, UNITED STATES NATIONAL MUSEUM 



by them when questioned about the wax-eating habits of the honey- 

 guides. To see whether barbets would eat wax I placed pieces of 

 dried, empty bee comb in the cages of two Asiatic barbets (Megalaima 

 asiatica and M. zeylonica) in the National Zoological Park, Washington, 

 D. C. For the next two weeks daily observations of the birds' eating 

 bits of the wax were recorded by Malcolm Davis, head keeper of the 

 bird house. This indicated that barbets apparently would eat wax, 

 but there was the disturbing possibility that this might have been, in 

 part at least, a generalized reaction to a strange object introduced 

 into a cage. In order to see how valid this objection might be, 

 similar pieces of bee comb were placed in the cages of a gi'eat variety 

 of other birds including a rufous motmot {Baryphthengus marti), red- 

 billed pie (Urocissa caerulea), Indian crow {Corvus insolens), white- 

 backed piping crow {Gymnorhina hypoleuca), naked-throated bell-bird 

 (Chasmorhynchus nudicollis), three species of turacos (Tauraco cory- 

 thaix, T. persa, and T. leucotis donaldsoni) , and three kinds of guinea- 

 fowl (Acryllium vuUurinum, Guttera eduardi schoutedeni, and G. 

 plumifera schubotzi) . None of these were ever seen to eat any of the 

 wax although they did peck at it and throw it out of their feeding 

 trays. 



The droppings of the two barbets were collected each day and were 

 crudely tested for possible wax content by heating them on the blade 

 of a spatula for melting, and by burning for waxy odor. Most of 

 them proved inconclusive, possibly because of the small amount of 

 wax ingested compared with the total bulk of the food eaten, but a 

 few of them did produce a waxy odor on burning. 



Somewhat similar to waxes are plant resins and gums. It may, 

 therefore, be worth mentioning that the giant bustard {Choriotis kori) 

 of Africa regularly feeds on the gum exuded from thorn trees of the 

 genus Acacia to the extent that its Afrikaans name, "gom paauw," 

 is derived from this habit. 



Other birds consume plant gums in smaller quantities, quite uninten- 

 tionally, and in these cases we have no reason for assuming any 

 nutritive use is made of these substances. To take but a single 

 example, we note that Lucian M. Turner (quoted by Bent, 1946, p. 

 380) found in Ungava that it was not uncommon for Acadian chick- 

 adees (Parus hudsonicus) to have their bills covered with gum from 

 spruce and larch trees. He accounts for it "by supposing that 

 during the summer months, when the gum exudes plentifully and is 

 so soft, many insects adhere to it, and when winter comes the birds 

 search for just such places to obtain the insects." The birds probably 

 swallow some of this gum with the insects. Plant gums are largely 

 hydrocarbons. 



