464 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



seen but 10 times seeking other food than sirup. In 1913 for 49 days 

 the drinking birds imbibed, and on nine occasions a humming bird 

 was seen gathering food elsewhere. In the 169 days that make the 

 grand total for the three summers, the rubythroats were seen drinking 

 sirup between one and two thousand times ; they were seen collecting 

 food away from the bottles 23 times ; but one can not be positive that 

 insect food was always taken then. Never for an instant was one of 

 these birds in captivity, and there was the utmost freedom for it in 

 choice of food. 



This choice of a sugar diet, together with the large amount con- 

 sumed, caused surprise, and soon called forth the estimate that a 

 humming bird would eat a teaspoonful of sugar in one day. Some 

 method of testing this estimate was sought, resulting in a plan for 

 putting the bottles beyond the reach of the ants that swarmed about 

 them. The stick that supported the artificial nasturtium and tiger 

 lily was nailed to a block of wood which was submerged in a flowerpot 

 filled with water. For a short time this arrangement served very 

 well, until leaves and flower petals fell in, forming rafts upon 

 which the ants were able to cross. No myrmecologist was at hand to 

 suggest a remedy, but at last the aversion of ants to kerosene was 

 recalled, and the water was covered with a film of kerosene, which 

 effectually debarred them. Nevertheless, one day the ants were 

 found taking the sirup as of old. An examination of existing con- 

 ditions showed that a grass stem had lodged against the supporting 

 stick, forming a bridge over which these wise little creatures were 

 busily passing to and fro. Except when the bottles were isolated in 

 this manner ants of various sizes and different colors fed constantly 

 on the sirup, often crowding a bottle to its very mouth, but this did 

 not prevent the birds from drinking. I am not prepared to say that 

 they never took an ant as food, but I have stood as closely as is 

 possible to a bottle while a humming bird was drinking from it, and 

 none was taken at such times. Wlien a new bottle was placed, or the 

 old ones were set out in the spring and filled, it took from one to two 

 days for the ants to find the sirup. A small red species generally, if 

 not always, was the ant to make the discovery, the fruits of which it 

 enjoyed for a very brief season, a large black ant soon taking pos- 

 session and holding the spoils for the rest of the summer. 



The bottles, having been removed from the encroachments of the 

 ants, were ready for the first test. One bird being the sole boarder 

 at that time, a level teaspoonful of sugar dissolved in water was 

 consumed by her daily. In time, two, three, four, and five humming 

 birds having joined her, the quantity of sugar was increased accord- 

 ingly, a spoonful or two being added to offset any possible waste. 

 In this way more than a pound of sugar was eaten in 20 days, or, to be 

 more exact, three cupfuls, weighing 9,252 grains, which made an 



