Life-Histories of the Booby and the Man-o'-War Bird. 14.S 



THE CAY VERDE COLONY. 



A partial census of eggs and young led to the conclusion that there 

 were about 1,500 pairs of boobies nesting on Cay \^erde. They were dis- 

 tributed in several groups, where the comparatively level surface and sandy 

 soil furnished favorable nesting conditions. In most instances the young 

 were covered with down, with the brown second plumage more or less evi- 

 dent in wings and tail. A few birds of the year were already a-wing and 

 several nests contained fresh eggs. For the greater number of birds, how- 

 ever, the nesting season, as Bryant has stated, evidently begins in February. 



THE AOULT BIRDS. 



One or both of the adults remain, as a rule, with the young. On March 

 9, the birds awoke at 5" 15° a. m., when for the ensuing 10 or 15 minutes 

 there was a subdued kind of quacking, and some birds were seen flying. 

 At 5'' 30™ several hundred birds left the rookery in a body to go a-fishing, 

 this being tiie first general movement. Individuals returned at intervals 

 during the day and evidently changed place.s with the bird left at the nest, 

 which in turn went out to feed and to gather fish for the young. There 

 was no concerted return movement until dusk, when flocks of birds came in 

 from the sea, the last-comers not arriving until after dark. In the meantime 

 the man-o'-war birds had retired, and it is not impossible that the boobies 

 have accjuired the habit of " staying out late " to avoid being robbed of their 

 food by the man-o'-war birds, which at times attacked them as they ap- 

 proached the cay and forced them to disgorge. 



Sitting or brooding birds spend the night upon the nest with the mates 

 standing at their sides, but the close resemblance of the sexes rendered it 

 impossible to distinguish them at this time. When the young is too large to 

 be brooded, it passes the night on the ground between the two parents, which 

 stand on either side, all three with their heads tucked under their scapulars. 



When perched on rocks about the border of the island, boobies showed 

 a decided fear of man and generally flew before one had approached to 

 within 30 yards of them ; but when on their nests they were conspicuously 

 tame, the degree of tameness being related to the advance of the nesting 

 season. A bird with newly hatched young would not, as a rule, leave the 

 nest unless actually forced to do so, and it would strike so viciously at any- 

 one approaching that it was well not to venture within its reach. This was 

 the extreme development of parental instinct, which now gradually dimin- 

 ished as the young increased in size. Evidently as a result of excitement 

 caused by our presence, the birds which remained to defend their young 

 threatened us with their bills, picked up bits of sticks or grasses only to drop 

 them and pick them up again, and even struck at their own 3'oung in a con- 

 fused and aimless maimer. The young also had this habit. The report of a 

 gun occasioned but little alarm among the boobies, some of which, with their 

 young near my feet, did not fly when the gun was discharged. 



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