10 



CALIFORNIA PISH A.ND GAM E 



Nest Material and Construction 



When a variety of nesl material is available the nests are usually 

 well made, bui. when the site is in a locality thai is devoid of vegetation 

 such as a canal bank or sand island, the tiesj is often little more than a 

 depression seratelird in 1 h .  ground and lined with down from £he 

 goose's breast (Fig. 8). 



In marshy areas where ronnd-stemmed tules (Scirpus acutus) and 

 three-square tules (Scirpus paludosus) are abundant, geese frequently 

 build nest mounds, often piling tide stems a.s high as three feet above 

 the ground or water level before beginning the construction of the 

 nest proper. Many of the tule stems used in the mounds or in nest 

 construction are broken from growing stalks. In some cases, areas 



Fig. 7. Typical mass of round -stemmed tule (Scirpus acutus), a favored nesting site. 



Photograph by James Moffltt. 



surrounding nests were denuded of tule growth for distances of from 

 three to 10 feet. 



When nests are built on haystacks, tule mats, muskrat houses, or 

 nest mounds, they are carefully constructed. A neat oval-shap ed 

 depression is usually made. 12 to 14 inches long, 8 to 10 inches wide, 

 and 5 to 8 inches deep. The actual construction of the nest usually 

 continues during the laying period, frequenl additions being made 

 until about the beginning of the period of incubation. It is not until 

 this time that the nest is finally lined with down. 



When the female leaves the nest for the feeding grounds, she care- 

 fully covers the eggs with down from the nest lining. The down is an 

 effective insulator; nests that have been left voluntarily by the incubat- 

 ing female on cool days have been found to contain warm eggs two 

 hours after she had left the nest. On hot days the down also acts as 

 an insulator against the heat of the sun. 



