450 THE DIVERS 



throated-diver is invariably found on the large and deep mountain 

 lakes, while the smaller, shallower, and often marshy pools are 

 inhabited solely by the redthroated species. Within twenty-four 

 hours of the time when the ice has disappeared, the Divers are always 

 to be found on the water. On one occasion Graf Zedlitz was able to 

 observe the act of pairing, and noted that it took place on land and 

 not on the water, as might have been expected. Its diving powers are 

 as great as those of the other members of this genus, and Seebohm 

 says that its flight is if anything swifter than that of its allies. Selby 

 timed one under water, and found that in a space of nearly two 

 minutes it had covered a distance of a quarter of a mile under water. 

 H. A. Macpherson times the period of immersion as one minute twenty 

 seconds to one minute thirty-five seconds, with intervals of two or 

 three minutes between the dives, in birds observed by him. The dives 

 were regular headers, the stern being the last to disappear. On the 

 whole it shows more readiness to take to the wing than the other 

 Divers, and Seebohm mentions that at a nest in the Petschora delta 

 both parents flew repeatedly overhead. 



Although the courtship of this species has never been described, 

 the late E. T. Booth witnessed some remarkable gatherings of adults 

 in summer. On 18th June 1868, he noticed half a dozen on a loch in 

 Sutherland, which were exceedingly animated, chasing one another 

 above and below the surface, and giving utterance while on the wing 

 and on the water to a variety of harsh cries, occasionally even yelping 

 like a dog. Another party seen three weeks later on Loch Craggie 

 was also sportively inclined, dashing about over the water with loud 

 cries, till a party of eight or ten passing over, they rose and joined 

 them, the whole making for Loch Shin. When flying thus in company, 

 they always kept in line one behind another at regular intervals. It 

 is possible that these gatherings, which sometimes reached fifteen or 

 twenty in number, consisted of birds which had been robbed of their 

 eggs, and were preparing to breed again, 1 or they may have been 



1 E. T. Booth, Rough Notes, vol. iii. 



