Letteratura scientifica selezionata sul tema "North Island brown kiwi"

The Moehau Kiwi Sanctuary is one of five sanctuaries established in 2000 and managed by the Department of Conservation. The objective of the sanctuaries is to protect the most endangered kiwi taxa, and increase kiwi survivorship. Operation Nest Egg (ONE) is a programme utilised by the Moehau Kiwi Sanctuary for artificially incubating abandoned Kiwi eggs and captive rearing chicks until they begin to show a gain in weight. ONE chicks were then released back onto Moehau or adjacent protected areas. Kiwi populations are declining on the mainland at an average of about 3% per year in areas where predators of kiwi are not controlled. The main cause for this decline is chick mortality due to predation by stoats (Mustela erminea). During natal dispersal kiwi are known to disperse significant distances of between 5–20 km, and this has influenced the size of management areas needed for the protection of kiwi (10,000 hectares). The type of forest-cover is an important element in determining where management areas are located, as kiwi has preferences for certain forest types over others. This study conducted at Moehau, Coromandel, on the North Island Brown Kiwi advances our knowledge of kiwi by examining differences in rates and distances of dispersal among chicks, sub-adults, non-territorial and territorial adults, as well as between genders. This study investigates kiwi selective use of roost site types, ground-cover types, forest types and physiographical features. Addressed in this study are differences in dispersal, habitat selection and mortality among age-classes and between genders over the months of the year, and across elevations. Comparisons between ONE and wild-reared kiwi dispersal and mortality are included. Data were collected between 2001 and 2008 from observations of kiwi located during daytime hours. The data recorded included the grid reference, elevation, ground-cover type, forest type, physiography, and the type of roost site. The sample size for this study was significantly larger than for any previous studies thus enabling a greater confidence in estimated dispersal rates and dispersal distances, habitat selection and factors relating to mortality. All wild-reared kiwi displayed dispersal and were not philopatric to their natal area. Dispersal distances were found to be further than previously estimated, with the net distance of natal dispersal differing among age-classes, from an average of 834m (SE +/- 131) for kiwi chicks to 7,553m (SE = +/- 1167) for non-territorial adults. Female sub-adult kiwi dispersed further (7,215m) than male sub-adult kiwi (4,226m) (p = 0.04). The time taken to travel one km during natal dispersal ranged from an average of 131days/km (SE = +/- 9) for chicks to 89 days/km (SE = +/- 13) for sub-adults. Habitat selection has been observed in other studies on kiwi but not specifically for Coromandel North Island Brown Kiwi, and selection for ground-cover types by kiwi when roosting on the surface has never been previously studied. Roost site selection of kiwi differed among age-classes (p <0.001), between gender (p <0.001), and across elevations (p <0.001). Female kiwi were found more often in surface roosts (64%) than hole roosts (32%), and male kiwi were found at similar frequencies in holes (46%) and on the surface (47%). Sub-adults used holes to a greater extent as elevation increased, and selected for sub-alpine forest over broadleaf forest (p <0.001). This study is the first to recognise that selection of ground-cover types by kiwi differs among age-classes (p <0.001). Kiwi chicks were more often found on the surface under dead fern fronds and debris (39%) than other ground-cover types. The mortality rate was highest in chicks (33%), with predation responsible for 60% of these deaths; conservation management techniques were responsible for a further 20% of deaths; the remaining 20% of deaths were due to natural or unknown causes. Summer (December-February) was the season in which 81% of kiwi chick deaths occurred. The high proportion of deaths from monitoring techniques and the use of radio-transmitters (22%) indicates improvements need to be made to current management practices. ONE chicks were found to disperse shorter distances and had a greater mortality rate than wild-reared chicks. Therefore, recommendations are made for changes to ONE management practices. Further recommendations are made for the enhancement of kiwi habitat that could reduce kiwi mortality, and for increasing the habitat available to kiwi, thereby potentially increasing population sizes and/or densities.

This thesis covers broad topics concerning limb growth and development and their effects on locomotion in the brown kiwi (Apteryx mantelli). I begin by describing the morphological features of a collection of unknown-age wild kiwi embryos from early development to point of hatch. Using these features, I assign developmental stages to each embryo and compare the progress of development to the same-staged ostrich and chicken embryos. Measurements of the hindlimb, bill and crown-rump length are used to develop an aging scheme based on comparisons with the ostrich and the chicken. The ostrich model and chicken model create age predictions for the unknown aged kiwi embryos. One kiwi embryo was of known age and both models gave identical predictions for this marker embryo, but gave differing predictions for all other kiwi embryos. Using captive-reared kiwi chicks, I characterise hindlimb, bill and bodyweight growth from the time of hatch to 3 months of age. Growth patterns are very linear within this time period for all measurements but bodyweight. Female kiwi hatch with longer bills than males, but the growth of both sexes converges by the end of the 3-month period. Growth of bodyweight in the males slows earlier than in females. Bodyweight and bill length were then compared to a wild population of kiwi. Captive-reared chicks were found to hatch with shorter bills than the wild birds and to increase in bodyweight at a faster rate than wild birds. Rapid weight gain has been implicated in developmental limb deformities in other precocial and long-legged birds and has the potential to produce similar results in captive kiwi. I further studied the movement of the hindlimb during locomotion in two adults and one juvenile kiwi by filming them while they were walking on a treadmill. Kinematic parameters were measured from the video recordings and compared to overground parameters from another study. Similarity between the treadmill and overground locomotor parameters validates the use of a treadmill in studying kiwi locomotion. None of the birds achieved the theoretical transition from a walk to a run at a duty factor of 0.5. After normalising for size, the juvenile showed a longer stride length and lower stride frequency with increasing speed than the adults. Lateral head oscillations were observed during the stride cycle, which I propose having a sensory function as well as a biomechanical one.

Possibly the most successful urban birds, pigeons and doves in the Order Columbiformes are one of the most easily recognised groups. They are an ancient and very successful group with an almost worldwide distribution and are most strongly represented in tropical and subtropical regions, including Australia. In most species simple plumage patterns feature mainly grey and brown with black, white or dull reddish markings, but the highly colourful fruit-doves include some of the most beautiful of all birds. From dense rainforests of north Queensland, where brilliantly plumaged Superb Fruit-Doves Ptilinopus superbus are heard more easily than seen, to cold, windswept heathlands of Tasmania, where Brush Bronzewings Phaps elegans are locally common, most regions of Australia are frequented by one or more species. For more than a century after arrival of the First Fleet, interest in these birds focused on the eating qualities of larger species. In addition to contributing to declines of local populations in some parts of Australia, excessive hunting brought about the extinction of two species on Lord Howe Island and another species on Norfolk Island. In Pigeons and Doves in Australia, Joseph Forshaw and William Cooper have summarised our current knowledge of all species, including those occurring on Christmas, Norfolk and Lord Howe Islands, and with superb artwork have given readers a visual appreciation of the birds in their natural habitats. Historical accounts of extinct species are also included. Detailed information on management practices for all species is presented, ensuring that Pigeons and Doves in Australia will become the standard reference work on these birds for ornithologists and aviculturists. Winner of a 2015 Whitley Awards Certificate of Commendation for Illustrated Text.

Islands are landmarks for sea birds, whether for orientation, as resting points during foraging and migration trips, or most importantly as nesting sites. This is due to the isolation that islands offer, rendering them free of many of the continental predators. If, additionally, islands are located in the midst of highly productive waters, they provide sea birds with abundant food, which is particularly valuable during the nesting season. This is the case in the northern Sea of Cortes. Not surprisingly, we find that the islands of this region are nesting sites for more than 90% of the world’s populations of Heermann’s Gulls (Larus heermanni) and Elegant Terns (Sterna elegans), and for about 90% of the global populations of the Least Storm-petrel (Oceanodroma microsoma), the Craven’s Murrelet (Synthliboramphus craveri), and the Yellow- footed Gull (Lams livens). The midriff island area of the Gulf of California also shelters approximately 70% of the world’s Black Storm-petrel (O. melania) and, at the subspecific level, provides breeding grounds for about 50% of the California Brown Pelicans (Pelecanus occidentalis californicus), 50% of the Blue-footed Boobies (Sula nebouxii nebouxii), and 40% of the Brown Boobies (S. leucogaster brewsteri). A combination of characteristics in one particular island, Rasa, has made it a natural breeding sanctuary for Heermann’s Gulls. Besides the two traits mentioned above (lack of land predators and high marine productivity), these characteristics include (1) its characteristic flat topography from which it derives its name (rasa means “flat” in Spanish), and (2) its sparse vegetation cover, resulting from the extensive coverage of the island with guano that hinders vegetation growth. The Heermann’s Gull is the only North American representative of the group of White-hooded Gulls (Anderson 1983; Moynihan 1959; Storer 1971). The only other member of this group of gulls and hence its closest relative is the Grey Gull (Lams modestus), which inhabits the Pacific coast of South America along Chile and Peru and breeds inland in the Atacama Desert some 50-100 km away from the coast (Howell et al. 1974; Howell 1978).

This chapter details how the author began to watch over wild birds along the north Florida coast. The author was a volunteer steward, and her first assignment was on a bit of sand, a spoil island south of the Apalachicola bridge. There, the author was to keep track of nesting activity by least terns, black skimmers, certain small plovers, or American oystercatchers. The island had historically hosted a seasonal congregation of 700 nesting pairs of brown pelicans. But after a large quantity of spoil was dredged from the river channel and heaped onto the island one winter, the pelicans abandoned the site and had never returned. Another year, more than 200 least terns and a handful of gull-billed terns had nested on the fresh spoil. It was not clear whether pelicans would return, or the terns — or neither.

Given Theirhistory Of Racial Subordination, how have black people gained any protection against the multifaceted forms of discrimination that threaten their well-being and undermine their rights? The answer can be stated simply: Black rights are recognized and protected when and only so long as policymakers perceive that such advances will further interests that are their primary concern. Throughout the history of civil rights policies, even the most serious injustices suffered by blacks, including slavery, segregation, and patterns of murderous violence, have been insufficient, standing alone, to gain real relief from any branch of government. Rather, relief from racial discrimination has come only when policymakers recognize that such relief will provide a clear benefit for the nation or portions of the populace. While nowhere mentioned in the Supreme Court’s Brown opinion, a major motivation for outlawing racial segregation in 1954, as opposed to the many failed opportunities in the past, was the major boost that this decision provided in our competition with communist governments abroad and the campaign to uproot subver­sive elements at home. This fortuity continues a long history of similar coincidences motivating the advancement or sacrifice of black interests. Three major examples of what I call interest-convergence covenants involve the abolition of slavery in the northern states, the Emancipation Proclamation, and the Civil War amendments to the Constitution. Lincoln’s issuance of the Emancipation Proclamation in 1863, and the divergent responses of blacks and whites to his action, were foreshad­owed by abolition policies in the northern states a half-century earlier. In the northern states, slavery was abolished by constitutional provi­sion in Vermont (1777), Ohio (1802), Illinois (1818), and Indiana (1816); by a judicial decision in Massachusetts (1783); by constitutional interpretation in New Hampshire (1857); and by gradual abolition acts in Pennsylvania (1780), Rhode Island (1784), Connecticut (1784 and 1797), New York (1799 and 1827), and New Jersey (1804). In varying degrees, abolition in the North was the result of several factors: idealism stemming from the Revolution with its “rights of man” ideology; the lesser dependence of the northern economy on a large labor force; the North’s relatively small investment in slaves combined with the great hostility of the white laboring class to the competition of slaves; the fear of slave revolts; and a general belief that there was no place for “inferior” blacks in the new societies.