Mating displays of Canvasback 



wings have reached the necessary stage of development. Until the duck has 

 completed its life cycle, which in most species covers a period of about 

 fifteen months (from birth to rearing of young and post-breeding molt), 

 new innate actions become ready for use as the need for their function 

 arises. The hen does not build her nest until she is nearly a year old; but 

 when nesting time arrives, the structure is completed without any previous 

 experience and is essentially the same as nests of her ancestors. Mating be- 

 havior, the displays and voicings characteristic of pair formation and nuptial 

 life, while they may see rudimentary expression during the natal or juvenile 

 period, are not fully developed until the bird enters its reproductive cycle. 

 We see, now, that the basic actions by which a duck meets its world 

 are inborn rather than learned. Notwithstanding the strength of this inborn 

 guidance, each bird's behavior is modified by learning; each individual 

 must learn to meet its environment. Lorenz ( 1935 ) clearly shows how the 

 object toward which an innate activity is directed may be learned. Examine, 

 for instance, the feeding actions. Eating movements are innate, but the ob- 

 ject toward which those actions are directed — food — is learned. A duck 

 learns what to eat and what not to eat. Furthermore it learns what foods it 

 prefers and those that are of secondary palatability. The development of 

 feeding behavior in captive-reared Canvasback ducklings at Delta is as 

 follows: First the feeding actions are indiscriminately directed toward al- 

 most any object the duckling encounters. This behavior begins in the incu- 

 bator when the birds, but a few hours old, explore the wire with their bills. 

 Then, when the ducklings are placed in brooder pens, the exploratory bill- 

 ings continue, nibbling at the wires, at the cloth screen, at straw and sticks. 

 Objects which are not food may be eaten. When, on their second day, 

 chopped egg is placed before them, it is billed only casually at first in this 

 random sampling. But the egg, of all objects in the pen, is edible; soon the 



16 



