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1.
As changes in land use have been identified as the main factor explaining the decline in Red-billed Chough Pyrrhocorax pyrrochorax populations across western Europe, a study was carried out in Ouessant (western France) in order to assess the relationship between territory quality and reproductive success. As such an approach could be hindered by the fact that the birds' reproductive performance could be influenced by their breeding experience, we analysed both inter- and intranest-site variation in fledging success. Territory quality was quantified, combining habitat selection, territory size, the amount of feeding area and distance between nest and feeding area. Feeding habitats selected positively by Red-billed Choughs were characterized by a mean sward height of less than 5 cm. Foraging area was on average 21 557 m2. Feeding areas (i.e. feeding habitat within foraging area) close to the nest were used preferentially. Fledging success appeared to be influenced neither by the total area of feeding sites in a Chough territory, nor by the mean feeding flight distance. However, fledging success adjusted to nest-site and year appeared to be influenced by feeding area close to the nest: one additional fledgling was expected for each additional 10 000 m2 of feeding habitat within 300 m of the nest. These first results allowed us to consider recommending landscape management measures to ensure a favourable conservation status of local Chough populations.  相似文献   

2.
The white stork Ciconia ciconia nest, with its impressive size of over 1.5 m in height, a diameter of over 1.5 m and weight exceeding a ton, belongs the largest and heaviest structures built by birds all over the world. This permanent construction which is made of long sticks laid in layers and the thick lining consisting of hay, straw, manure, rubbish and rags, could last for decades. During that time, it can be an attractive shelter and breeding site for many organisms, including small birds, mammals and arthropods. However, due to some methodological constraints, the role of such nests for the diversity of saproxylic insects has not been well recognized so far. Here we report the first observation of occurrence of larvae of obligate saproxylic marbled rose-chafer, Protaetia lugubris (Cetoniinae) inside the white stork nest. We further discuss that the interior of a long-term stork nest may be an alternative to interiors of tree hollows in which typically most chafer’s larvae develop. Thus, white stork nest could provide supplementary habitat for saproxylic beetles of conservation interests.  相似文献   

3.
Capsule An increase in new nest building in a white stork population revealed that they were built further from human settlement and on non-typical structures; such nests had lower breeding success resulting from later breeding.

Aim To determine why some birds build new nests rather than occupy older ones, and how new nests affect breeding performance compared to old nests, in a long-lived bird, the white stork.

Methods We compared new nest construction in 2010 with a long-term data set on white stork in Western Poland from 1974 to 2009. For data from 2010, we analysed nest location and breeding biology in detail.

Results Since 1974, the proportion of new build nests was ca. 1.6%; in 2010 this was 13.2%. Pairs in new nests bred later than pairs in old, and had smaller clutches and lower breeding success. New nests were located further from settlements and tended to be built on different structures. A significantly lower proportion of new nests were re-occupied in subsequent years.

Conclusions Pairs may build new nests to gain experience in nest building, cooperation and foraging for subsequent seasons or because of competitive pressure when the environment is close to carrying capacity. Breeding success can be initially very low.  相似文献   

4.
The effect of supplementary food on the reproductive success of Black-billed Magpies Pica pica was studied in an urban habitat in the city of Edmonton, Alberta, Canada. We provided supplementary food (pelleted dog food) regularly from August 1986 to June 1988 in a feeder situated outside all known magpie territories. Magpies using the supplementary food showed (i) an advancement of 7 days in the initiation of laying, (ii) no increase in clutch-size, (iii) higher survival of nest contents (eggs and young) during a spring snow storm, (iv) an increase in rate of nestling weight gain, and (v) an increase in fledging success. Supplementary food did not prompt the fed pairs to select nest sites nearer the feeder in 1988 than in 1987. The feeder did not affect the breeding density because the nearest neighbour distances of fed magpies did not differ from unfed magpies in either year, nor did they differ between the two years for either fed or unfed magpies. This study provided evidence that magpies frequently renest even if their initial nests fail after the eggs hatch—a practice that has been reported to be absent or rare in other studies. Although brood reduction was equally frequent in the nests of food-supplemented and control pairs, the actual number of nestlings disappearing from the former (1.56 per nest) was significantly smaller than that from the latter (2.60 per nest), suggesting that the availability of food plays a major role in magpie reproductive success.  相似文献   

5.
Understanding the mechanisms that shape density‐dependent processes and population dynamics is often essential for species conservation. Two key mechanisms of density‐dependent reductions in reproductive performance are a limited access to foraging habitats (the habitat heterogeneity hypothesis) and territorial aggression towards conspecifics (the interference competition hypothesis) at high population densities. Disentangling the relative importance of these mechanisms within populations below their carrying capacity is important for the evaluation of the success of conservation measures. However, relatively few studies have attempted to quantify the relative importance of both mechanisms for the reproductive performance of a population. Many raptor populations are ideal model systems to investigate density‐dependent effects because they are currently recovering from human‐induced reductions during the last decades. Using a 14‐year dataset, we combined analyses of individual reproductive performance with a mechanistic population model to investigate early signs of density‐dependent regulation in a population of White‐tailed Eagles Haliaeetus albicilla in north‐east Germany. We found a negative effect of the number of neighbouring breeding pairs and a positive effect of water surface area (as a proxy for the availability of favourable foraging habitat) on breeding success and on the average number of nestlings. The mean nearest neighbour distance between breeding pairs has decreased, and the mean distance of nests to the nearest water body has increased over the last 14 years. Moreover, the population model indicates that even though the population is still growing, carrying capacity could be reached at about 500–950 territorial pairs. These results suggest that the selection of nesting sites is determined by a trade‐off between the distance to favourable foraging habitat and the distance to neighbouring breeding pairs. To avoid increasing competition with conspecifics, due to continued population growth, breeding pairs seem to select increasingly suboptimal habitats. Therefore, our results suggest that the habitat heterogeneity and interference competition hypotheses are not necessarily mutually exclusive as mechanisms of density‐dependent population regulation, but can determine the reproductive performance of a raptor population simultaneously. Thus, a future decline in breeding success does not necessarily reflect a decrease in habitat quality but may rather be a consequence of density‐dependent mechanisms. This information may be useful for the interpretation of population trends and for the development of appropriate management strategies for recovering raptor populations.  相似文献   

6.
Abstract: White‐winged choughs (Corcorax melanorhamphos, Corcoracidae) are a common, breeding resident in and around the city of Canberra in the Australian Capital Territory. We compared five measures of reproductive success between the urban and non‐urban populations of choughs to investigate the effect of urbanization on this cooperatively breeding species. Urban choughs initiated breeding earlier than their non‐urban counterparts and were more likely to suffer nest failures. However, there was no difference in the number of successful nests in a season or the number of fledglings produced per successful nesting attempt. A greater proportion of fledglings survived their first 12 months in the non‐urban habitat. We suggest that increased rates of nest predation and fledgling mortality in the urban environment may have a negative effect on reproductive success and remove any advantage that might be gained through a longer breeding season. Possible effects of urbanization on the social and genetic structure of white‐winged choughs are also discussed.  相似文献   

7.
We studied the size and productivity of white stork (Ciconia ciconia) populations in eight study sites in Poland. The number of nesting pairs and the average number of chicks fledged per pair fluctuated over time, and the studied populations differed in the variance of both breeding success and number of breeding pairs. The variance of breeding success (both for the mean number of chicks and the proportion of successful nests) and the variance of the number of breeding pairs was not correlated with the extent of stable habitats (pastures, meadows, wetlands), other habitats (farmland), or with local population trends over time. We found a non-linear symmetrical relationship between annual mean reproductive success and its variance but only when considered as the proportion of successful nests (i.e., when individual nests are coded as a binary value: 0, no success; 1, success). No such relationship existed when success was expressed as the number of fledged chicks. Although a positive significant correlation occurred between fledgling numbers (discrete data) and the proportion of successful nests (binary data), we believe that the use of only binary data will be inadequate in more detailed analyses, such as population viability analysis.  相似文献   

8.
ABSTRACT.   Forest fragmentation can create negative edge effects that reduce the reproductive success of birds nesting near the forest/nonforest interface, and threaten bird populations deeper in remnant forest habitats. Negative edge effects may be more pronounced in landscapes that are moderately fragmented, particularly where agriculture is the primary land-use fragmenting forests. Information about the extent and strength of edge effects at a site can help guide conservation actions, and determine their effectiveness. We examined edge effects for birds breeding in a nearly contiguous forest fragmented by relatively narrow agricultural corridors in Illinois (USA). We measured rates of nest predation and brood parasitism for Acadian Flycatchers ( Empidonax virescens ) over a continuum of distances from the edge of an agricultural inholding. Nest predation and brood parasitism were highest near the edge and decreased with increasing distance from the edge. Given the cumulative effects of nest predation and brood parasitism on reproductive success, we determined that forest within 600 m of the inholding was sink habitat. We found, however, that deeper forest interior areas currently serve as source habitat, and that conversion of the entire 205 ha agricultural corridor to forest would add 1350 ha of source habitat for Acadian Flycatchers. Such results provide support for a local conservation strategy of forest consolidation and establish baseline measures necessary to determine the relative effectiveness of any subsequent reforestation efforts.  相似文献   

9.
In metapopulations in which habitat patches vary in quality and occupancy it can be complicated to calculate the net time-averaged contribution to reproduction of particular populations. Surprisingly, few indices have been proposed for this purpose. We combined occupancy, abundance, frequency of occurrence, and reproductive success to determine the net value of different sites through time and applied this method to a bird of conservation concern. The Tricolored Blackbird (Agelaius tricolor) has experienced large population declines, is the most colonial songbird in North America, is largely confined to California, and breeds itinerantly in multiple habitat types. It has had chronically low reproductive success in recent years. Although young produced per nest have previously been compared across habitats, no study has simultaneously considered site occupancy and reproductive success. Combining occupancy, abundance, frequency of occurrence, reproductive success and nest failure rate we found that that large colonies in grain fields fail frequently because of nest destruction due to harvest prior to fledging. Consequently, net time-averaged reproductive output is low compared to colonies in non-native Himalayan blackberry or thistles, and native stinging nettles. Cattail marshes have intermediate reproductive output, but their reproductive output might be improved by active management. Harvest of grain-field colonies necessitates either promoting delay of harvest or creating alternative, more secure nesting habitats. Stinging nettle and marsh colonies offer the main potential sources for restoration or native habitat creation. From 2005–2011 breeding site occupancy declined 3x faster than new breeding colonies were formed, indicating a rapid decline in occupancy. Total abundance showed a similar decline. Causes of variation in the value for reproduction of nesting substrates and factors behind continuing population declines merit urgent investigation. The method we employ should be useful in other metapopulation studies for calculating time-averaged reproductive output for different sites.  相似文献   

10.
Facultative shifts in nesting habitat selection in response to perceived predation risk may allow animals to increase the survival probability of sessile offspring. Previous studies on this behavioral strategy have primarily focused on single attributes, such as the distance moved or changes in nesting substrate. However, nest site choice often encompasses multiple habitat elements at both the nest site and nest patch scales. We studied the within-season re-nesting strategy of a multi-brooded songbird, the Brewer’s sparrow (Spizella breweri), to determine whether pairs utilized a “win-stay, lose-switch” decision rule with respect to inter-nest distance, nest substrate and/or nest patch characteristics in response to previous nest fate. Pairs moved sequential nest sites slightly farther following nest predation versus success. When inter-nest distance was controlled, however, pairs changed nest patch attributes (shrub height, potential nest shrub density) associated with probability of nest predation to a greater extent following nest predation than success. The strategy appeared to be adaptive; daily nest survival probability for previously depredated pairs increased with greater Euclidian habitat distances between attempts, whereas previously successful pairs were more likely to fledge second attempts when nest sites were similar to those of previous attempts. Our results suggest that nesting birds can use prior information and within-season plasticity in response to nest predation to increase re-nesting success, which may be a critical behavioral strategy within complex nest predator environments. Re-nesting site selection strategies also appeared to integrate multiple habitat components and inter-nest distances. The consideration of such proximate, facultative responses to predation risk may clarify often unexplained variation in habitat preferences and requirements.  相似文献   

11.
Hoi H  Krištín A  Valera F  Hoi C 《Oecologia》2012,169(1):117-124
In order to understand habitat selection, it is important to consider the way individual animals assess the suitability of a future reproductive site. One way of investigating mechanisms (such as those involved in nest site selection) is to examine breeding success and habitat characteristics in terms of animals returning to a place where they have already reproduced and using the same location over successive years or searching for new alternatives. This approach seems especially suitable for testing recent hypotheses suggesting that nest site selection is an integrative process that includes the use of social information (e.g. past breeding success of conspecifics). Determining the factors that elicit conservative or innovative behaviour regarding nest-site selection could be important for improving our understanding of habitat selection decisions in animals. More than half of the nests of the long-distance migratory lesser grey shrike Lanius minor, are built in the same or neighbouring trees. We found no evidence that habitat characteristics influence nest-site tradition. On the contrary, social information in terms of the presence of conspecifics and past reproductive success in terms of complete nest failures due to nest predation (but not detailed information such as variation in fledgling number) influenced nest-site tradition. Hence, social information and past reproductive success may play a role in nest-site choice in this species. Our results further demonstrate that previous experience with a nest site does not appear to be beneficial.  相似文献   

12.
Capsule: The Dupont’s Lark Chersophilus duponti in Iberia has relatively high breeding success in both core and fragmented habitats, so population declines are more likely to be the result of low juvenile or adult survival.

Aims: To measure important aspects of the reproductive biology of one of the most endangered and least known larks: the Dupont’s Lark C. duponti.

Methods: We monitored 36 nests in 2 Spanish shrub-steppes, one holding one of the largest European populations (250 pairs) and one composed by fragmented habitat patches holding a smaller population (50 pairs).

Results: The breeding season went from late-March to early July. Overall mean (±sd) clutch size was 3.47?±?0.56, and the number of fledglings per successful nest was 3.0?±?1.15. Mean nestling period was short (8.2 days). Nests showed similar daily survival rate during the incubation period (0.9750?±?0.0110) as during the nestling period (0.9545?±?0.0168), with a mean breeding success of 50%. Predation was the main cause of complete nest failure (83.3% of failed nests in both localities).

Conclusion: Breeding parameters did show no significant variation between populations. Breeding success in both sites was generally higher than recorded in previous studies of this and most other lark species, which suggests that breeding success does not compromise long-term viability of these populations. The decline of the studied populations should be explained by other causes, such as a general decrease in habitat quality, habitat loss or habitat fragmentation.  相似文献   

13.
Anthropogenic landscapes can be rich in resources, and may in some cases provide potential habitat for species whose natural habitat has declined. We used remote videography to assess whether reintroducing individuals of the threatened New Zealand falcon Falco novaeseelandiae into a highly modified agricultural habitat affected the feeding rates of breeding falcons or related breeding behavior such as nest attendance and brooding rates. Over 2,800 recording hours of footage were used to compare the behavior of falcons living in six natural nests (in unmanaged, hilly terrain between 4 km and 20 km from the nearest vineyard), with that of four breeding falcon pairs that had been transported into vineyards and nested within 500 m of the nearest vineyard. Falcons in vineyard nests had higher feeding rates, higher nest attendance, and higher brooding rates. As chick age increased, parents in vineyard nests fed chicks a greater amount of total prey and larger prey items on average than did parents in hill nests. Parents with larger broods brought in larger prey items and a greater total sum of prey biomass. Nevertheless, chicks in nests containing siblings received less daily biomass per individual than single chicks. Some of these results can be attributed to the supplementary feeding of falcons in vineyards. However, even after removing supplementary food from our analysis, falcons in vineyards still fed larger prey items to chicks than did parents in hill nests, suggesting that the anthropogenic habitat may be a viable source of quality food. Although agricultural regions globally are rarely associated with raptor conservation, these results suggest that translocating New Zealand falcons into vineyards has potential for the conservation of this species.  相似文献   

14.
Habitat loss, electrocution on power poles and persecution by humans are the main threats to birds of prey. Nevertheless, the effects of human disturbance on endangered species are becoming notorious due to the increasing recreational use of the natural environment. We evaluated the effects of human disturbances on Egyptian vulture Neophron percnopterus breeding success and developed conservation measures based on minimum distance of effect and buffer areas in a high human density area of northern Spain. A total of 100 breeding attempts of 15 breeding pairs were monitored over 8 years. Human disturbances affected 42 of the breeding attempts. Those disturbances related to and originating in forestry work had the most severe effect on breeding success, being associated with the loss of 100% of 13 breeding attempts, while human disturbances related to free-time activities caused 44% failures in 25 breeding attempts by four pairs, two of them within Natural Parks. The breeding success was significantly less in territories affected by disturbances than in those free of disturbances. Some pairs affected by disturbances changed their nest site, increasing breeding success. Adults were prevented from entering the nest to feed chicks when anyone was detected at an average distance of 307 m, while an average distance of 837.5 m allowed them access. The maximum alert distance was estimated at 605 m and the buffer area was 57 ha. We discuss the application of our results for management schemes and conservation of this species.  相似文献   

15.
Lõhmus  Asko  Runnel  Kadri  Palo  Anneli  Leis  Mare  Nellis  Renno  Rannap  Riinu  Remm  Liina  Rosenvald  Raul  Lõhmus  Piret 《Biodiversity and Conservation》2021,30(12):3647-3664

Protecting habitats for charismatic vertebrates can provide an ‘umbrella’ for less conspicuous organisms, especially when these are threatened by the same processes. However, such a conservation scheme is vulnerable to the extirpation of the focal species. We studied wider biodiversity values in long protected black stork (Ciconia nigra) nest sites, which were abandoned by the bird and thus legally subject to de-listing. In 20 abandoned nest sites in Estonia, we (i) mapped breeding birds within 600 m from the stork nest, and (ii) carried out time-limited surveys of lichens, polypore fungi, vascular plants and bryophytes in 2-ha plots. The breeding bird assemblages (64 species recorded) included 19 red-listed species, and showed no clear aggregation to the immediate surroundings of the stork nest. We recorded 740 plant and fungal species, of which 134 (18%) were of conservation concern (nationally protected, red-listed or extremely rare). Across the 2-ha plots, the numbers of the species of conservation concern varied more than three-fold (maximum 42 species), being affected notably by dead wood accumulation over time and presence of nemoral broad-leaved trees. The results demonstrate that many abandoned nest sites of the black stork have broader biodiversity significance, both due to the bird’s habitat requirements and the natural development during the protection. Expanding the umbrella function to sites abandoned by a focal species, but intact from anthropogenic degradation, can thus be a cost-effective conservation approach due to its low additional administrative burden. In most jurisdictions, the assessment procedure for such situations should be formalized, however.

  相似文献   

16.
Factors affecting avian demography and abundance in urban landscapes are poorly understood and this hinders attempts to manage urban bird communities. Several recent studies indicate that lack of invertebrate prey in urban landscapes may constrain avian productivity and fitness relative to that in other habitats. House Sparrow Passer domesticus populations have undergone large declines in many European urban centres and inadequate reproductive success linked to invertebrate availability has been postulated as a potential cause of these declines. We conducted a replicated supplementary feeding experiment to test whether the availability of invertebrate prey limits the breeding success and adult abundance (colony size) of House Sparrows in suburban London, where House Sparrow populations declined by 60% during the decade preceding our study. Daily mealworm provision over two successive breeding seasons, sufficient to provide 82% of chick energy requirements of House Sparrow pairs nesting within 50 m of feeders, had a large positive impact on the abundance of recently fledged birds (+62%), but only a small positive impact, limited mainly to small colonies, on the overall abundance of territorial males. Colony growth was only weakly related to fledgling abundance in the previous year and did not appear to be constrained by nest‐site availability. Conservation interventions that enhance invertebrate availability for suburban House Sparrows may increase reproductive success but are unlikely, on their own, to lead to population growth or recovery.  相似文献   

17.
Understanding breeding phenology and success can elucidate population dynamics, which is especially important for species in need of conservation. We describe the factors affecting the breeding biology of American Oystercatchers (Haematopus palliatus frazari) at El Rancho Island, a critical site that contains ~ 7% of the total estimated population, on the coast of Sinaloa, Mexico. We monitored 192 nests over four years (2016–2019). The breeding season lasted from March to June and mean laying dates differed among years, with the mean laying date in 2019 an average of 20 days earlier than in 2016. Clutch sizes decreased as the breeding season progressed. Both breeding success and productivity differed among years, with the lowest values in 2016 (30% hatching success and 0.6 chicks/nest) and the highest in 2019 (66% hatching success and 1.2 chicks/nest). Hatching success was affected by year, laying date, type of habitat, and distance to the high tide line. American Oystercatchers that laid eggs earlier in the season, used mixed marsh and dune habitat, and with nests relatively close to the waterline (< 50 m) had greater breeding success. Overall, however, the breeding success of American Oystercatchers was low and influenced by a combination of several intrinsic and extrinsic factors. Management measures may be required to increase breeding success and ensure the conservation of this subspecies.  相似文献   

18.
In countries such as the UK, USA and Australia, approximately half of all households provide supplementary food for wild birds, making this the public's most common form of active engagement with nature. Year‐round supplementary feeding is currently encouraged by major conservation charities in the UK as it is thought to be of benefit to bird conservation. However, little is understood about how the provision of supplementary food affects the behaviour and ecology of target and non‐target species. Given the scale of supplementary feeding, any negative effects may have important implications for conservation. Potential nest predators are abundant in urban areas and some species frequently visit supplementary feeding stations. We assess whether providing supplementary food affects the likelihood of nest predation in the vicinity of the feeder, by acting as a point attractant for potential nest predators. We provided feeding stations (empty, peanut feeder, peanut feeder with guard to exclude potential nest predators) in an area of suburban parkland in the UK and monitored the predation rate of eggs placed in artificial nests located at distances that replicated the size of typical suburban gardens. Nest predators (Magpies Pica pica, Grey Squirrels Sciurus carolinensis) were frequent visitors to filled feeders, and predation caused by Magpies, European Jays Garrulus glandarius and Grey Squirrels was significantly higher when nests were adjacent to filled feeders. The presence of a feeder guard did not significantly reduce nest predation. As supplementary feeding is becoming increasingly common during the breeding season in suburban habitats, we suggest that providing point attractants to nest predators at this time may have previously unconsidered consequences for the breeding success of urban birds.  相似文献   

19.
2008和2009年3—6月,在黄河三角洲自然保护区采用定点观察、GPS定位、样方调查和逐步判别分析等方法对东方白鹳(Ciconia boyciana)繁殖期觅食地的利用进行了研究。共测定了75个觅食利用样方和74个对照样方的14个生态因子。结果表明,东方白鹳繁殖期倾向于在明水面、芦苇沼泽和滩地中觅食,对草地和农田利用极少。偏向于食物丰富度较高的觅食点;对隐蔽级高低没有明显的偏好。对利用样方和对照样方进行比较,发现利用样方具有植被高度和植被盖度较低,觅食地水深相对较浅,距明水面、芦苇沼泽、树林等距离较近,距重度干扰源较远等特征。逐步判别分析表明,距芦苇沼泽距离、样方内水深、距重度干扰源距离、食物丰富度和明水面距离具有重要作用,由这5个变量构成的方程在对繁殖季节东方白鹳觅食地利用样方和对照样方进行区分时,正确判别率可以达到95.5%。东方白鹳繁殖期觅食地的利用主要与水源、人为干扰和食物条件有关。  相似文献   

20.
JAN KOMDEUR 《Ibis》1996,138(3):485-498
The total population of the Seychelles Magpie Robin Copsychus sechellarum declined from 38–41 birds in 12–13 territories in 1977–1978 to 17–21 birds in eight to nine territories in 1988–1990 and was entirely confined to Fregate Island (210 ha) in the Seychelles. After a successful cat eradication program in 1981–1982, recruitment improved, although the abandonment of agriculture had caused a reduction in the amount of feeding habitat and hence in the carrying capacity of the island. The population declined because of the failure of recruitment to compensate for the annual adult mortality. Foraging activity of the Magpie Robin was greater in high-quality territories (measured by soil invertebrates available), leading to increased reproductive success. Through supplementary feeding, five times as many recruits were produced. Of the 11.5 potential annual breeding recruits, 5.3 are required to compensate for adult mortality, and the other 6.2 recruits can be regarded as “surplus” contributing to an increase. Magpie Robins prefer to breed in rotten trees, which are a scarce resource. The greater the distance between the nest site and feeding areas, the less time was spent in incubation and nest guarding, resulting in greater egg loss. Because of lack of suitable areas for establishing territories, many young Magpie Robins became “floaters”. Nest disturbance, both by these floaters and by the introduced Indian Mynah Acridotheres tristis, had adverse effects on the breeding success of robins. A recovery plan has been designed to save the Magpie Robin. Territories have been improved for feeding (by tree planting) and for breeding (by providing nestboxes and reducing nest disturbances). Given the vulnerability of one small island, the presence of surplus birds (supported mainly by supplementary food) and the suitability of neighbouring Aride Island (68 ha), successful translocations to this island took place in 1992 and 1994. Given the presence now of 47 individuals on two islands, it is hoped that the species will pull back from the brink of extinction.  相似文献   

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