94 Papers from the Marine Biological Laboratory at Tortugas. 



and sooties leaving the island singly and in small groups. They apparently 

 continue their flight until the jumping schools of small fish meet their eye. 

 This may happen soon or late ; consequently they may feed near the island or 

 far away. 



Apparently, at the end of 2 hours the noddy has supplied its needs, for 

 at this time it returns to the island and relieves its mate at the nest. The 

 latter then comes out upon the water and takes, roughly, a two-hour turn at 

 fishing, then likewise returns to the nest. This routine of spending 2 hours 

 at the nest and 2 hours on the water is engaged in by all of the noddies dur- 

 ing the seasons of brooding and of rearing the young (see p. 206 1. Before 

 the egg is laid, however, the male does the fishing for both himself and the 

 female at intervals which I could not determine. The male sooty, on the 

 other hand, as will be shown later, during the laying and brooding season 

 probably stays out upon the water all day long, returning at nightfall during 

 the former season to feed the female, and during the latter season to take his 

 turn at brooding the egg (see p. 209). 



I was especially anxious to determine the distance to which the terns go 

 for their food. I have the following observations to report bearing upon 

 this subject: So far as I could learn from questioning the residents at Key 

 West, 65.8 statute miles to the east, these birds never venture as far as that 

 for food. The lighthouse-keeper at Rebecca Shoal Light,^ 17 knots distant 

 from Bird Key (east), tells me that he has never seen either of these 

 species of birds fishing in that locality. He reports that on sunny days 

 pelicans, frigate-birds, cormorants, boobies, etc., appear there in large num- 

 bers. I am inclined to think that his statements with respect to the terns are 

 correct. Both on approaching Bird Key from the east and upon leaving it 

 to the west, I was not able to observe these birds feeding farther out that 4 

 to 10 knots. As a final test in the matter I made a trip, with the assistance 

 of Mr. Kellner and Mr. Hooker, in the laboratory launch. The chart is 

 shown by the dotted lines in figure i. We left Bird Key at 8'' 30 in the 

 morning and journeyed in a straight line almost to Rebecca Shoal Light. 

 The birds were seen fishing in numbers until a distance of 9 or 10 knots had 

 been traversed, after which fewer and fewer birds were sighted. From 13 

 knots on to 15 no birds were sighted. At this point we stopped and waited 

 for an hour. No birds appeared. In returning to the island, we partially 

 retraced our path and then turned toward the south and steered in a circle, 

 keeping Bird Key within about 10 knots. On the return trip, 20 birds were 

 counted before we began to circle the island. Just as the turn was made 

 to the south, three large groups were seen feeding, and from that point on 

 the birds were numerous. 



From my own observations I conclude that these birds rarely leave the 



' See fig. I, p. 192. 



