302 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



hundreds and were evidently preparing to lay, yet in two females taken two 

 or three days after my arrival the eggs in the ovaries were very small. 



Soon after sunset the birds came in to roost among the low bushes fringing 

 the shore, and up to a late hour many kept arriving. They flew very swiftly, 

 just skimming the surface of the water, and standing on the shore at dusk 

 (the time they began to arrive) it was rarely possible to see the birds coming 

 until they were actually on the island. They alighted noiselessly and instantly 

 on gaining the fringing bushes; later in the mouth, however, as their numbers 

 increased, belated birds found difficulty in effecting an easy landing among the 

 branches, those already in possession pecking right and left at all newcomers 

 and croaking harshly. Each day, as their numbers increased, they became more 

 vociferous, until at last the melancholy wail of those flying overhead and the 

 croak of the sitting birds was kept up without intermission all through the 

 night. On moonlight nights they appeared unusually abundant and restless. 



I have watched them thei'e until far into the night, as in scores they kept 

 flying to and from the bushes. Although up and about before dawn on most 

 mornings, I was seldom in time to watch the noddies leave their roost. One 

 morning, however, I got a good idea of their numbers. It wanted about an 

 hour or so of daybreak, and the moon was still bright, when someone walking 

 along the shore appeared to give a general alarm. Scores of birds got up and 

 went swiftly out to sea, and for some little time a constant stream poured out 

 from the bushes along the shores in every direction, as far as it was possible 

 to see; flying before the wind, they went out of sight in an instant. They left 

 the land always in the same manner in which they came in to roost, dropping 

 to the surface of the water immediately on clearing the shore. Notwithstanding 

 their apparent abundance, the noddies, in point of numbers, sink into compara- 

 tive insignificance after the arrival of the sooty terns. 



Prof. John B, Watson (1908) has made a most thorough and 

 scientific study of the behavior of this species and the sooty tern on 

 their famous breeding grounds in the Dry Tortugas and I shall quote 

 freely from the published results of his observations. He describes 

 the island on which they nest as follows : 



Bird Key is a small coral island about 300 yards wide (east and west) by 

 400 yards long (north and south). It is 6.5.8 statute miles due west from Key 

 West. The island is partially sheltered on the east and on the northeast by 

 a coral reef. Northeast of the island, about 1.12.5 statute miles distant, stands 

 Fort Jefferson, now practically deserted. Still farther to the northeast other 

 low coral islands are to be found. Loggerhead Key lies about 4 statute miles 

 to the west of Bird Key. Immediately outside of these islands is to be found 

 the water of the Gulf of Mexico. The situation of the island shows that it is 

 adequately protected from all but the severest southwest storms. The Tortugas 

 as a whole are rarely subject to heavy storms during the nesting period of the 

 birds. During the past season (1907) only one severe storm visited the island, 

 and this was not very destructive to the life of the birds. 



Owing to its juxta-tropical location, its slight elevation, and the condition of 

 its surface (largely coral sand) the actual surface temperature of this island 

 is very high, ranging at times during the hottest days from 124° to 143° F. 



With the exception of the bay-cedar bushes, which are very abundant upon 

 the central and western parts of this island, little vegetation exists. On a cer- 

 tain limited portion of its surface (southeastern) a dense growth of cactus is 

 to be found. Both cactus and bay cedars are utilized by the noddies for nesting 

 places. 



