116 



THE OSPREY. 



anna's hummingbird, trochilus anna, from life, (see page 126.) 

 Copyrighted by Dougherty & Grinnell, Pasadena, Cal. 



about two beats in three seconds. To my wonder the surface. The wing-beats must necessarily be in 

 most of the diving horizontally was performed with opposition to that tendency. To accomplish this 

 the belly upward and back downward, that is, in a with the same set of muscles and the same shape of 

 reverse position to that during flight through air. I wing as used in aerial locomotion, the bird must dive 

 do not think this was an exceptional case on account with belly upward, or with upward strokes of the 

 of the disablement of the bird, and on second thought wings. The point of support in order to maintain 

 it does not seem strange. an upright position of a bird's body in air must be 



When a bird flies through air it has gravity to above the centre of gravity. So that to prevent the 

 overcome, besides the resistance of the air while body of a bird flying through water from rolling from 

 moving forward. Therefore the wing-beats are down- side to side, the support for keeping the bird from 

 wards and slightly backwards. But in water the rising, must be below the centre of bouyancy. 

 Murrelet was lighter than its displaced volume of On several occasions in following Murrelets, I 

 water, therefore it was constantly tending to rise to noticed that a bird would appear in a direction op- 

 posite to that in which it faced at the 

 moment of diving. I was thus fooled, and 

 at first lost track of many Murrelets. I 

 think that the birds dove straight down- 

 wards for a few feet, and then directed 

 themselves backwards, flying with belly 

 upward, as just described, appearing again 

 in an opposite direction, but facing, as at 

 first. 



They always dive under so quickly that 

 the eye receives only the slightest impres- 

 sion of the vanishing tail, and but little 

 ripple is left. They cannot be shot when 

 alarmed and on their guard as they dive 

 before the charge can reach them. The 

 length of time these birds remain under 

 water is not so long as might be supposed 

 They commonly come to the surface at 

 intervals of seldom more than one minute, 

 though when pursued only the head may 

 appear, and then only for an instant, 

 often before one discovers it. One might 

 thus be led to believe that they stay down 



,,^„„^ much longer than in reality. Sometimes 



annas hummingbird feeding young. s -' 



Copyrighted by Dougherty & Grinnell, Pasadena, Cal. the Murrelets take to wing as soon as ap- 



