78 MISSOURI BOTANICAL GARDEN. 



winged aerial acrobat is not measured by our miles, hundreds 

 of which he daily traverses without effort in his ordinary vo- 

 cation of gnat consumer. Thousands of gnats and midges 

 are found buried in the stomach of this useful bird, whose 

 capacious mouth is coated with a sticky saUva enabhng him 

 to capture scores of the minute insects by a single sweep with, 

 open mouth through a cloud of them. 



RUBY-THROATED HUMMINGBIRD. TrOchUuS COluhnS. 



Since the cold spring of 1907 Hummingbirds are not so com- 

 mon as they used to be. Birds are all more or less subject to 

 numerical changes, brought about by a variety of agencies. 

 A few heavy downpours of rain in June, killing the tender 

 young, will greatly reduce the number of a species in a sec- 

 tion of the country, as with such short-lived creatures as 

 small birds the omission of one year's progeny would reduce 

 the number of those returning to us the following spring by 

 at least one-third. Especially the insectivorous birds, to 

 which we must count the Hummer in spite of its fondness for 

 nectar, suffer by a cool summer. Swallows and Swifts are 

 sometimes visibly reduced, the latter chiefly by continuous 

 rains at the time when they have small young in their frail 

 nest, which, only glued to the wall, is loosened by the rain and 

 falls with its contents to the bottom of the chimney. 



Hummingbirds are not known to nest in the Garden, but 

 become common among its flowers in the latter part of July, 

 when migration from the north begins to reach us. Stopping 

 in favorite places, they drift leisurely southward, spending 

 three months in the transit through the United States. The 

 males, traveling faster than the females and young ones, are 

 nearly all gone by the middle of September, but the last of 

 the species do not leave St. Louis before October. The 

 drought of the summer and fall of 1908 caused earlier depart- 

 ure than usual, when nectar and insects became scarce and 

 the flowers themselves withered. Jewel weed, usually a great 

 favorite till October, had no attraction after the middle of 

 September. As the red pollen of the Red Buckeye leaves an 

 imprint on the Hummingbird's throat in early spring, so does 



