340 Papers from the Marine Biological Laboratory at Tortugas. 



Eighth day: 



The 5th, 6th, and 7th days are characterized by the appearance of the 

 fighting Veaction. This is full-fledged and well coordinated. From this 

 time on I had to exert great care in keeping the young birds from injuring 

 one another. Fighting is indulged in at any and all times unless the birds 

 are covered. Apparently there is never any cause to evoke this reaction 

 other than the mere visual stimulus of a bird nearby. On the 8th day the 

 birds began to hop clown from the box (a height of 3 inches) and to run 

 to meet me. 



Nil! til day: 



The birds have formed a great attachment for me. They will follow 

 me all around the room. It is becoming more and more difficult to keep 

 them in any box. They will clamber up to the top of the box if any means 

 are at hand and will jump down from a height of 8 to 10 inches. 



Eleventh day: 



Birds are now forced to eat without any assistance from me. They learn 

 this more rapidly than do the sooties, for the reason that theadult noddy in 

 feeding its young sometimes disgorges the food upon the rim of the nest. 

 The birds soon learn to pick up the fish from the floor, regardless of whether 

 the fish are squirming or still. 



Twelfth and thirteenth days: 



These days show a notable strengthening in all of their instinctive re- 

 sponses. They peck frequently at small objects and have much more 

 accurate aim. They rarely take the object into the mouth. The fights 

 are now prolonged and furious. From further observation of the birds 

 in the field I find that the pecking reaction is utilized by the young birds 

 in controlling the movements of the parents. By means of it the young 

 birds force the parents to cover them. When I cover the young birds with 

 the hand thev stop pecking. If I so arrange my fingers that they can not 

 huddle tmderneath my hand, they continue striking it until the proper move- 

 ment on mv part is made to admit the bird under the cover of the hand. 

 Once it receives the extended contact of the hand it gives a contented 

 little " querk," which causes the others to hasten up and to huddle under- 

 neath the hand. 



The nest habits of the birds of this age and older were noticed to-day 

 for the first time. The nest is kept clean by means of their peculiar habits 

 of defecation. The bird usually remains in the center of the nest. When 

 defecation becomes necessary the bird backs quickly to the rim of the nest, 

 stops suddenly, and forces 'the fecal matter far out over the rim (some- 

 times 8 to 10 inches). The interior of the nest is never soiled.^ 



The birds in captivity, even when on a perfectly smooth floor, held to 

 the same habits of defecation. The birds were turned loose on the floor 

 at this age. They began pecking very definitely at all small objects in sight, 

 for example, my tan shoe-lace, a spot on the toe of my shoe, grains of coral 

 sand, bits of feathers, strings, small sticks, and matches. No attempt was 

 made to swallow the small articles except in the case of the match. Three 

 birds did attempt, however, to swallow this. 



' I have seen an adult noddy when defecated upon by another bird fly immedi- 

 ately to the water and begin bathing. 



