The Scientific Bases for the Preservation of the Hawaiian Crow (1992) / Chapter Skim
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7 FINDINGS AND RECOMMENDATIONS
7 FINDINGS AND RECOMMENDATIONS
Pages 90-107
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From page 90... ...
. Limited banding data and census efforts in the Kona District during the 1970s and 198Os indicate that during this period of precipitous decline, clutch size for the 'Alala is at the low end of what has been found to be typical of that of other Corvus species; nesting pairs of 'Alala continued to produce fledglings at the McCandless Ranch at rates slightly lower than those of other corvids, and even lower elsewhere; and juvenile survival (up to ~ year)
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From page 91... ...
They could provide critical, traditional experience for newly released, naive 'Alala being reintroduced into formerly occupied temtor~es. However, contingency plans for He wild population must be developed in the event that the strategy proposed above falls.
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From page 92... ...
when the wild population is known to be less Can two breeding pairs for two consecutive years, and 2) state-of-the-art breeding facilities exist on the Hawaiian islands and the captive population is reproducing well.
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From page 93... ...
It also recommends that such a program include other creative manipulations of the habit to protect habim patches on ranches from the impacts of came and other herbivores, so as to restore and maintain the essence features of crow habit in sufficient quantity and quality for viable populations of crows and other native species A, Dlant.£ and' animus to be secure for the indefinite future. -rig ~ rim" ~ During the 'Alala's recovery period, He cooperation of ranches in He Nicety of He remnant wild population wall be vital.
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From page 94... ...
AD four can be maintained in good quanta on cattle ranches. If property-managers condor or prevent clearing and grazing in cndcal areas of sufficient size and dis~ibudon, 'Alala territories ought to be able to persist indefinitely in cathe-ranch settings on Be Kona slopes.
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From page 95... ...
Because 'Alala will frequency nest in Me same locations from year to year, nest trees should be protected by electrical predator guards or aluminum flashing during the breeding season. Solar-powered electric guards have been used successfully on Guam to protect Marianas Crow nests from predation by brown tree snakes (Boiga irregulars)
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From page 96... ...
The following long-term actions that require planning, cooperation, and coordination of sever parties are recommended: · Improve the 'Alala's habitat through forest management and other practices Hat promote important fruit-beanng plants and substrates for invertebrates. · Institute a long-term study of avian malana at appropriate elevations on the Kona slopes.
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From page 97... ...
Such data will provide specific direction for management of the property that supports the final wild population, of adjacent properties as 'Alala numbers increase, and of additional forest preserves after reintroduction or recolonization. The following pages summarize the kinds of data and observations that are most needed to help guide management of habitat as 'Alala numbers increase.
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From page 98... ...
, the limiting factors condoning dispersal and recruitment of this resource should be determined, especially the effect of grazing or rooting by cattle and pigs. Characteristics of nest sites and their vicinity should be identified, especially quantitative descriptions of the structure of vegetation, plant composition, and extent of native understory habitat within 250 m of the nest trees.
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From page 99... ...
Inference through He study of over bird species is now required, and it is essential. The following are some questions that need furler examination: · What are the ~nfechon rates of avian malaria and avian pox among introduced arid nadve forest birds at 1,500 m on He Kona slope, both on and off He McCandIess Ranch?
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From page 100... ...
The nature of dispersal forays by prebreeders should be studied, as well as Me age at which Key begin, how far they move, whether dispersers regularly return to the natal family group, and to what habitats and elevations dispersing nonbreeders are attracted. As to the degree of terntonal aggression during the nonbreeding season, do family groups (including adjacent temtonal pairs)
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From page 101... ...
· A more natural environment in the form of planted Divines, rawer Han wooden The following specific features require planning, cooperation, arid coordination of several parties: · A second captive-breeding facility should be developed to provide increased security from disease or other catastrophes. This second facility should be developed in Hawai'i and its collection should be restricted to endemic Hawaiian species.
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From page 102... ...
- Check semen quality of males and relate it to known history of avian pox infection. · Modify breeding enclosures so Hat male birds can be removed from the nesting site as soon as mates lay their first eggs.
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From page 103... ...
This "target" population size should be adjusted upward or downward depending on the effectiveness of other management strategies for Increasing He size of Be wild population. Any additions to the captive stock should be made first by taking first clutches of wild eggs arid incubating them in the laboratory, second, by taking nestlings or recent fledglings, and third by taking some nonbreed~ng adults.
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From page 104... ...
· Sex of birds according to laparoscopy performed by a qualified avian veterinarian and application of chromosomal techniques to feathers. · Institution of artificial ~nseminabon techniques In the captive population of 'Alala win semen from a male nonbreeder and an imprinted female if initial breeding attempts are unsuccessful or result In the production of Infertile eggs.
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From page 105... ...
An accurate nutritional analysis of food items in the wild is needed, and consideration should be given to simplifying the diet in captivity to ensure proper and consistent nutrition. Equipment at the Captiv - Breeding Facility Recommendation IS: Equipment shout be modernized to ensure the success of the captive-breeding progrmn.
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From page 106... ...
Lack of molecular data about historical and current levels of genetic vanabon in the wild population have prevented meaningful ~nvesUgabon of the genetic implications of the 'Alala's decline. In any case, the 'Alala population on the McCandless Ranch is so close to the wild sources of some of He captive birds that Hey would be expected to add no more than very slight genetic variability to He captive population, and even the current magnitude of vanabon win be retained only if He population is rapidly increased.
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From page 107... ...
It is clear that the preservation of genetic diversity in both the captive and wild populations will require that these populations be increased in size as rapidly as possible. Until the wild and captive populations increase substantially, demographic considerations should remain the principal determinants of management activities.
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