Leaves, twigs, and down are used to cover eggs 

 when the incubating bird leaves to forage (Hawaii 

 Div. Fish and Game 1972). 



RITUAL REQUIREMENTS 



Nene are more jealous and quarrelsome than 

 is common among geese. The gander defends his 

 territory, mate, and brood savagely, but some- 

 times exhibits the unusual behavior of attacking 

 his own mate (Delacour 1954). 



POPULATION NUMBERS AND TRENDS 



The wild population may have totaled 25,000 

 or more in the 18th century. Reduction began 

 between 1778 and 1850, progressed rapidly until 

 1900, and tapered off slowly between 1900 and 

 1930. In 1953, the estimated population of wild 

 birds was only 33 (Baldwin 1945). Smith (1952) 

 estimated the total population in the wild at less 

 than 30. Since 1940, coincident with conserva- 

 tion efforts, the population has obviously increased 

 if the earlier estimates were reasonably correct. 

 Counts on the summer roosting area near Puu Oo 

 Ranch north of the Saddle Road on the southeast 

 slope of Mauna Kea have ranged from 42 in 1966 

 to 114 in 1969. An increase during the 17 years 

 of counting in that area (since 1955) was in- 

 dicated, although inconsistent. About 90% of 

 birds in the summer roosting area are unhanded 

 and presumed to be wild rather than pen-reared 

 (Hawaii Div. Fish and Game 1972). 



The number of individual birds observed with 

 eggs or young in the three nene sanctuaries have 

 been: 1966, 2; 1967, 32; 1968, 36; 1969, 12; 

 1970, 16; 1971, 12. Of these parent birds, 40% 

 were banded, indicating they were released pen- 

 reared birds; and 60% were unhanded, indicating 

 they were either wild or offspring of released 

 birds. There is no indication of a new population 

 developing from releases on the new sanctuary at 

 Kipuka Ainahou, northeast of Mauna Loa be- 

 tween Access Road and Saddle Road (Hawaii Div. 

 Fish and Game 1972). 



Counts of introduced population on Maui re- 

 corded 43, with 2 produced in the wild in August 

 1973; 45 were seen in October 1974, with un- 

 handed birds shovwng up increasingly. Nests or 

 young were found in 1972 and 1974 (Monthly re- 



ports of Hawaii Div. Fish and Game). 



The actual number of nene in the wild is un- 

 known!. The "educated guess" is at least 600 wild 

 and released birds and their progeny on Hawaii 

 and a third as many more (200) on Maui (Wood- 

 side in Zimmerman 1974). 



REPRODUCTION 



Clutch size has been reported as 5 to 8 eggs 

 (Delacour 1954), although 3 to 5 eggs per clutch 

 were recorded for the wild population on Hawaii 

 and the captive birds at Pohakuloa. The incuba- 

 tion period is 28 to 31 days (Ripley 1965). 



The nesting season may run from October 

 through March. February to late May is a flight- 

 less period for young and a molting period for 

 adults (Ripley 1965). Wild pigs, dogs, cats and 

 mongooses may threaten nene eggs and goslings 

 and even adult birds during the 4- to 6-week 

 flightless period (N. Santos m Zimmerman 1975). 

 Young grow slowly, requiring 10 to 12 weeks to 

 reach the flying stage; this is nearly twice the time 

 required by Canada geese. Adults are completely 

 grounded for 4 to 6 weeks by the wing molt; 

 thus, part or all of the nene family may be vulner- 

 able to ground predators for 3 months or more 

 each year (Elder and Woodside 1958). Breeding 

 potential is low because they rarely reach sexual 

 maturity or lay fertile eggs in captivity until 3 

 years of age or more. Six pairs observed in the 

 wild produced an average of only 2 young annually 

 (Elder and Woodside 1958). 



In the captive flock at Shmbridge, England, 

 the sex ratio is equal. Sixty-two percent laid eggs 

 at the end of their second year. Ganders between 

 their fourth and eighth years have fertilized the 

 most eggs. Females laid the most fertile eggs in 

 their fourth year. Clutch size at Shmbridge aver- 

 aged 3.95 eggs, compared to 3.7 at Pohakuloa, 

 Hawaii. In Hawaii, nene lay their first eggs in 

 November; in England, about 9 February. Day 

 length, rather than temperature, is thought to 

 induce breeding. Long days inhibit breeding and 

 induce molting (Kier et al. 1967). 



In the captive flock at Pohakuloa, inbreeding 

 of original stock was determined to be the cause 

 of low fertility; infusion of a new wild bird strain 

 and selection of birds for productivity greatly in- 

 creased fertility. Fertility increased with age of 

 breeders to 75% at 15 years in the Shipman strain 

 and to 100% at 8 years in the wild strain. Dates of 



