LIFE HISTOKIES OF NORTH AMERICAN GULLS AND TEENS. 



303 



No accurate data exist concerning the number of years these two species have 

 migrated to this island for the purpose of rearing their young. The oldest 

 inhabitants of the neighborhood say that as long as they can remember the 

 birds have been going there year after year. The terns arrive at approximately 

 the same time each year (during the last week in April), live there until toward 

 the 1st of September, and then begin, their southern migration. 



, Courtship. -^ The birds are said to be mated before they arrive on 

 the island, and, as he did not arrive until five days later than the 

 birds, Prof. Watson was unable to observe their earlier actions; 

 but he tentatively presents the following account of what is probably 

 a mating performance : 



One day I observed several noddies " sunning " upon the wire covering of one 

 of my large experimental cages. Suddenly, one of the birds (male) began nod- 

 ding and bowing to a bird standing near (female) I The female gave immediate 

 attention and began efforts to extract fish from the throat of the male. The 

 male would first make efforts to disgorge, then put the tip of the beak almost to 

 the ground and incline it to the angle most suitable to admit her beak. She 

 Would then thrust her beak into his (the ordinary feeding reaction). The 

 feeding reaction was alternated with the nodding. After this series of acts 

 had been repeated 20 times the male flew off and brought a stick. He de- 

 posited this near the female, and; then again offered to feed her. She again tried 

 to feed ; then the male attempted sexual relations. She immediately flew away, 

 but almost immediately returned and alighted at a slightly different place. The 

 male again brought the stick and again bowed and offered to feed her. She 

 accepted the food, but again flew away when the male attempted to mount her. 

 At this juncture the island was disturbed and my observations could not con- 

 tinue. 



Nesting. — During his sojourn on Bird Key in 1907 he made an 

 accurate count of the noddies' nests "by means of a mechanical 

 counting device," "which gave a total of 603 active nests. A large 

 majority of the nests are built in the bay-cedar bushes at varying 

 heights up to about 12 feet. About 20 per cent of them are in the 

 cactus growth. : 



Very often the nest has the appearance of being constructed directly upon 

 the ground, but a closer examination usually shows that it has been built upon 

 a tuft of grass or upon the stem of a bush, the branches of which have been 

 broken off close to the ground. * ' * ' * ' The noddies apparently do not seek 

 to nest in the thickest parts of the bushes. Although isolated nests are 

 present even where the shrubs are most dense, by far the majority of them 

 are to be found in bushes which border upon open spaces. 



Of the construction of . %h& nest he says : 



The noddy constructs its nest from (1) loose dead branches of the bay- 

 cedar bushes; (2) of seaweed; (3) of a combination of these; (4) of a com- 

 bination of either or both of these with various kinds of sea shells and coral 

 When the shells and coral are employed they are often placed as an inner 

 lining to the nest and the 1 egg is deposited directly upon them. The nest itself 

 is a quite variable structure and usually loosely put together. It is very 

 shallow, and this is rather singular, since the wind often blows the egg or the 

 young to the ground. 



