DISPERSAL AND MIGRATIONS 173 



of the way without a pause or rest ! What we 

 do know respecting the flight of birds, and espe- 

 cially a long-sustained flight, is quite contrary to 

 these wonderful estimates. The Homing Pigeon 

 record for several successive hours is, we believe, 

 under sixty miles per hour ; but, aided by a gale, 

 a speed of 2150 yards per minute has been 

 reached. When we come to the relative speed 

 of migration, however, we are on much surer 

 ground. The Baltimore Oriole, by a very care- 

 ful series of observations, has been found to 

 travel at the rate of twenty-seven miles per day ; 

 the record of fifty-eight species gave an average 

 of twenty-three miles per day. The records also 

 tend to show that the smaller land birds do not 

 perform long journeys over land at one time. 

 King Birds have been estimated to do forty miles 

 in a single night, but, exceptionally, as many as 

 100 or even 200 miles in the same period of time. 

 At present, however, there is absolutely no reli- 

 able data upon which to speculate. The height 

 at which migrating birds fly is also very interest- 

 ing. Without ascending to a considerable altitude 

 the migrations of many birds would be simply 

 impossible. Most birds appear to fly high during 

 migration. Birds have been often observed on 

 passage flying at a height of from one to two 



