NESTING CANADA GEESE IN HONEY LAKE VALLEY, CALIFORNIA 17 



cause of death to be aspergillosis, a fungus infection of the respiratory 

 tract. 



The cause of eight unsuccessful nestings was undetermined. 



Egg Fertility 



During the 1940 season, a record of egg fertility was kept on 127 

 successful nests. These nests contained a total of 697 eggs or an 

 average of 5.48 eggs per nest. Six hundred and forty-nine or 93 per 

 cent of the eggs produced goslings. 



Williams and Marshall (1937) reported an average clutch of 4.8 



eggs and a hatch of 81 per cent for a total of 84 nests and 410 eggs. 



Of the 48 eggs that did not hatch, 16 or 33.3 per cent were 

 infertile. In 17 or 35.3 per cent there were partially developed 

 embryos, and in 15 or 31.4 per cent of the eggs the goslings were well 

 developed but had died before hatching. In each of the latter cases, 

 the yolk sac was still unabsorbed. 



Three unhatched eggs were found in each of three successful nests. 

 These eggs all contained dead, partly-developed embryos. No doubt 

 these eggs were deposited by another female goose after incubation of 

 the original clutch had started, and the extra eggs were abandoned 

 after the original clutch had hatched. 



With the exception of the three cases noted above, all of the other 

 unhatched eggs were found singly. 



Management 



It is possible that through the application of management methods 

 the number of geese produced annually in Honey Lake Valley may be 

 increased. 



The control of predators, particularly coyotes, in the prenesting 

 season will prove to be an effective management tool. Some coyote 

 control work is being carried on in the valley at the present time, but 

 it is not intensive enough to give the required amount of protection 

 to the geese during the nesting season. 



Where it is practicable and compatible with the other interests of 

 an agricultural community, the more efficient control of water levels 

 will result in the elimination of losses due to the flooding of nesting 

 sites. 



The writer has already mentioned that losses due to fire were 

 prevented in 1940 by inducing ranchers to complete tule burning opera- 

 tions prior to the nesting season. The continuance of this practice 

 should be encouraged. In view of the cooperative attitude of the 

 ranchers, it may also be possible to eliminate losses caused by drags 

 used to level meadow land during the spring months and by ditch and 

 levee cleaning operations. 



It is important that tule masses, which are favored nesting sites, 

 be left unburned where their presence will not interfere with farming 

 operations. Additional nesting sites may be provided by the construc- 

 tion of islands in Hartson Reservoir and along the margins of Honey 

 Lake. 



3—18211 



