Determination of the presence of Mycobacterium avium on Guam as a precursor to reintroduction of indigenous bird species

1998 ◽  
Vol 4 (3) ◽  
pp. 227
Author(s):  
Ilse Silva-Krott ◽  
M. Kelly Brock ◽  
Randall E. Junge
Keyword(s):  
Mycobacterium Avium ◽  
Captive Breeding ◽  
Bird Species ◽  
Animal Husbandry ◽  
Breeding Population ◽  
Native Forest ◽  
Captive Population ◽  
Boiga Irregularis ◽  
Bird Populations ◽  
High Degree

Eight of 11 native forest bird species on Guam were extirpated by the introduction of the Brown Tree Snake Boiga irregularis. Emergency measures necessary to rescue the Guam subspecies of Micronesian Kingfisher Halcyon cinnamomina cinnamomina from extinction involved translocation and captive breeding in American mainland zoos. Soon after the establishment of a captive breeding population, the kingfisher demonstrated a high degree of susceptibility to avian tuberculosis (ATB), a disease that proved to be a major threat to the preservation of the species. The cause of ATB is Mycobacterium avium which produces a prolonged course of infection in kingfishers and other birds. Kingfishers infected with M. avium are difficult to detect until late in the course of the disease, thereby potentially posing a risk of transmitting ATB to the Guam captive population of Guam Rails Gallirallus owstoni, if kingfishers are repatriated. M. avium is considered to be ubiquitous in nature. However, there are no reported mortalities due to ATB in any bird species on Guam. In this study, six of twenty-one cultures yielded Mycobacterium spp., two of which were further identified as M. avium. Since this study demonstrates that M. avium already exists on Guam, repatriating kingfishers to Guam poses no threat of introducing a new pathological agent to the island's ecosystem. Strict quarantine procedures along with rigorous animal husbandry protocols should minimize risks of repatriating infected kingfishers to Guam, and prevent transmission of ATB to the captive population of Guam Rails and other bird populations on Guam.

scholarly journals Recent recovery and expansion of Guam’s locally endangered Såli (Micronesian Starling) Aplonis opaca population in the presence of the invasive brown treesnake

2021 ◽  
pp. 1-16
Author(s):  
HENRY S. POLLOCK ◽  
MARTIN KASTNER ◽  
GARY J. WILES ◽  
HUGO THIERRY ◽  
LAURA BARNHART DUEÑAS ◽  
...  
Keyword(s):  
World War Ii ◽  
Urban Areas ◽  
Native Species ◽  
Bird Species ◽  
Control Measures ◽  
Population Increase ◽  
Native Forest ◽  
Boiga Irregularis ◽  
Bird Populations ◽  
Brown Treesnake

Summary Assessing the impacts of invasive predators on the demography and distribution of native species is critical for understanding mechanisms of species persistence and informing the design of recovery programmes. On the oceanic island of Guam, the introduction of the predatory brown treesnake Boiga irregularis after World War II caused the near-total loss of the native forest avifauna. Localised snake control measures have been implemented since the early 1990s, yet it remains poorly understood how they have impacted Guam’s remaining native bird populations. To address this question, we combined intensive area searches of Andersen Air Force Base (AAFB) with island-wide transect surveys and opportunistic sightings to provide a comprehensive update on the distribution and abundance of Såli (Micronesian Starling, Aplonis opaca) – one of Guam’s last extant native bird species. Area searches of AAFB, where the largest remnant of the Såli population persists, revealed a 15-fold population increase since the last survey in the early 1990s, and transect surveys and opportunistic sightings indicate incipient recolonisation of other urbanised areas of northern and central Guam. We estimate the current island-wide population size at ~1,400 individuals. The population increase can likely be attributed to a combination of snake control measures and the Såli’s ability to exploit urban refugia for nesting and roosting. Although these trends demonstrate some population recovery, a skewed age ratio (>90% adults and subadults) at AAFB and a highly urbanised distribution and low abundance outside AAFB indicate that snake predation continues to strongly impact the population. More intensive snake suppression efforts, particularly in forested areas, may allow for the Såli population to attain its former distribution and abundance on Guam. More broadly, our findings reinforce the importance of urban areas as refugia for some threatened species.

scholarly journals Increased nesting success of Hawaii Elepaio in response to the removal of invasive black rats

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
Paul C Banko ◽  
Kelly A Jaenecke ◽  
Robert W Peck ◽  
Kevin W Brinck
Keyword(s):  
Forest Restoration ◽  
Nest Success ◽  
Rattus Rattus ◽  
Bird Species ◽  
Oceanic Islands ◽  
Nesting Success ◽  
Native Forest ◽  
Forest Bird ◽  
Bird Populations ◽  
Black Rats

Abstract In Hawaii and other oceanic islands with few native land mammals, black rats (Rattus rattus) are among the most damaging invasive vertebrate species to native forest bird populations and habitats, due to their arboreal behavior and generalist foraging habits and habitat use. We evaluated the nesting response of Hawaii Elepaio (Chasiempis sandwichensis; Monarchidae), a generalist insectivore, to the removal of black rats using rodenticide in a before-after-control-impact study in high- and low-elevation mesic montane habitat recovering from long-term damage from introduced ungulates and weeds. We monitored nesting success and rat abundance during 2015–2016 before applying rodenticide bait in 2017 to remove rats from two 700 × 700 m treatment plots that were paired with 2 nontreatment plots of the same size. Rat abundance was reduced by 90% during treatment, with combined variables treatment and elevation best explaining the change using GLM methods and AIC model selection. The daily survival rate (DSR) of nests (n = 191) was greater on treated plots after rodenticide application (mean ± SE = 0.980 ± 0.004 treatment; 0.964 ± 0.004 nontreatment), modeled nest success increased from 29% to 50%, and apparent nest success (number of successful nests per total nests) increased from 37% to 52%. The most informative model for predicting DSR included the effect of treatment. Predation by rats was documented at 3 of 16 nests using video surveillance, and we observed additional evidence of rat predation during in-person nest monitoring. Rats targeted adults on the nest and sometimes removed intact eggs, leaving little trace of their activity. Our results demonstrate that reducing rat predation can immediately improve the nesting success of even a common bird species in habitat with a long history of forest restoration. Sustained predator control may be critical to accelerating the recovery of native forest bird communities.

Application of a PCR-based approach to identify sex in Hawaiian honeycreepers (Drepanidinae)

2000 ◽  
Vol 6 (1) ◽  
pp. 14 ◽  
Author(s):  
Susan I. Jarvi ◽  
Susan I. Jarvi ◽  
Paul C. Banko ◽  
Paul C. Banko
Keyword(s):  
Endangered Species ◽  
Conservation Genetics ◽  
Reliable Method ◽  
Captive Breeding ◽  
Bird Species ◽  
Molecular Techniques ◽  
Hawaiian Honeycreepers ◽  
Breeding Programmes ◽  
Degree Of Confidence ◽  
High Degree

The application of molecular techniques to conservation genetics issues can provide important guidance criteria for management of endangered species. The results from this study establish that PCR-based approaches for sex determination developed in other bird species (Griffiths and Tiwari 1995; Griffiths et al. 1996, 1998; Ellegren 1996) can be applied with a high degree of confidence to at least four species of Hawaiian honeycreepers. This provides a rapid, reliable method with which population managers can optimize sex ratios within populations of endangered species that are subject to artificial manipulation through captive breeding programmes or geographic translocation.

scholarly journals Evolution of Avian Conservation Breeding With Insights for Addressing the Current Extinction Crisis

2010 ◽  
Vol 1 (2) ◽  
pp. 189-210 ◽  
Author(s):  
Jesse D'Elia
Keyword(s):  
Captive Breeding ◽  
Bird Species ◽  
Historical Review ◽  
Population Expansion ◽  
Natural History Museums ◽  
Avian Conservation ◽  
Bird Populations ◽  
Exotic Animals ◽  
In Captivity ◽  
Conservation Breeding

Abstract Birds have been bred in captivity since the dawn of civilization. In the nineteenth century, breeding rare and exotic animals for the menageries of royalty and aristocrats transitioned to the formation of public zoological gardens and natural history museums. With industrialization and human population expansion, some bird species became rare or disappeared entirely. Once the magnitude of the destructive forces of humans became evident, concerted efforts were initiated to restore depleted bird populations by using, among other techniques, captive breeding. In this article, I explore the evolution of avian conservation breeding programs and evaluate how this historical review informs our outlook for addressing the current extinction crisis.

scholarly journals The dynamics of avicultural markets

2001 ◽  
Vol 28 (1) ◽  
pp. 76-85 ◽  
Author(s):  
Jennifer M. Robinson
Keyword(s):  
Captive Breeding ◽  
Bird Species ◽  
Decision Makers ◽  
Trade Restrictions ◽  
Model Simulations ◽  
Species Introductions ◽  
Bird Populations ◽  
Potential Source ◽  
The World

Trade restrictions stemming from the Convention on International Trade in Endangered Species (CITES) have created a situation in which rare and attractive bird species command high prices on international pet markets. Most of these species are of tropical or subtropical origin, and many are amenable to captive breeding. Hence, the possibility of exporting birds under CITES provisions for the export of captive-raised animals is under debate in many countries around the world. If export bans are replaced by systems of export permits, the economics of avicultural markets will govern the magnitude, timing, and nature of the impacts of the bird trade. Avicultural economics, however, is little studied, and the long-term economic viabilities of exotic pet markets are poorly understood. In order to elucidate these, a dynamic model of an avicultural market was constructed, based on descriptive information. Model simulations showed that the high prices commanded by sought-after bird species tended to bring about oversupply and rapid price decline. Short-lived, fecund species produced a rapid, sharp pulse of oversupply; longer-lived species produced more persistent but less acute conditions of oversupply. The present high prices for protected bird species may be regarded as a potential source of windfall profits, or as a factor that might be manipulated to discourage the poaching and smuggling of wild birds. If export-oriented aviculture is considered as a component of strategies for diversification of agriculture and promotion of sustainable development, it is important that decision-makers factor in the likelihood of significant declines in bird prices and that they consider the risk of accidental species introductions that is inherent in holding large exotic-bird populations.

scholarly journals Pervasive impacts of invasive brown treesnakes drive low fledgling survival in endangered Micronesian Starlings (Aplonis opaca) on Guam

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
Henry S Pollock ◽  
Julie A Savidge ◽  
Martin Kastner ◽  
Thomas F Seibert ◽  
Todd M Jones
Keyword(s):  
Survival Rates ◽  
Bird Species ◽  
Forest Edge ◽  
Life History Stage ◽  
Native Forest ◽  
Boiga Irregularis ◽  
Nest Location ◽  
Nest Boxes ◽  
Invasive Predators ◽  
Fledgling Survival

Abstract Invasive predators have caused widespread loss of biodiversity in island ecosystems, yet certain species are able to tolerate the presence of generalist invaders. For example, the invasive brown treesnake (BTS; Boiga irregularis) caused the extirpation of 10 of 12 native forest bird species on the island of Guam, but a remnant population of the Micronesian Starling (Aplonis opaca), or Såli, has managed to persist on a military installation in northern Guam. Understanding how Micronesian Starlings are coping with the presence of BTS can inform conservation efforts for island bird populations facing invasive predators and provide insight into strategies for expanding the starling population. We monitored the survival, movements, and habitat use of 43 radio-tagged starling fledglings during this vulnerable life-history stage. Invasive predators accounted for 75% of fledgling mortality (56% from BTS; 19% from feral cats) and contributed to one of the lowest post-fledging survival rates (38% through day 21 post-fledging) recorded for passerine birds. Predation by BTS persisted at elevated rates following natal dispersal, further reducing cumulative survival to 26% through 53 days post-fledging. Nest location was an important predictor of survival: fledglings from nest boxes closer to the forest edge were more likely to use forest habitat at younger ages and more likely to be depredated by BTS. Overall, our findings indicate that BTS continue to severely impact Guam’s starling population, even more so than invasive predators affect native birds in other island systems. We recommend deploying nest boxes farther from the forest to improve fledgling survival and implementing urban predator control to promote growth of the Micronesian Starling population on Guam and facilitate future reintroductions of other species.

scholarly journals How many bird extinctions have we prevented?

Oryx ◽  
2006 ◽  
Vol 40 (3) ◽  
pp. 266-278 ◽  
Author(s):  
Stuart H.M. Butchart ◽  
Alison J. Stattersfield ◽  
Nigel J. Collar
Keyword(s):  
Invasive Species ◽  
Captive Breeding ◽  
Extinction Risk ◽  
Bird Species ◽  
Iucn Red List ◽  
Additional Species ◽  
Conservation Actions ◽  
Declining Populations ◽  
Population Sizes ◽  
Principal Actions

Considerable resources and efforts have been directed at biodiversity conservation in recent years, but measures of the success of conservation programmes have been limited. Based on information on population sizes, trends, threatening processes and the nature and intensity of conservation actions implemented during 1994–2004, we assessed that 16 bird species would have probably become extinct during this period if conservation programmes for them had not been undertaken. The mean minimum population size of these 16 species increased from 34 to 147 breeding individuals during 1994–2004. In 1994, 63% of them had declining populations but by 2004, 81% were increasing. Most of these species (63%) are found on islands. The principal threats that led to their decline were habitat loss and degradation (88%), invasive species (50%) and exploitation (38%), a pattern similar to that for other threatened species, but with exploitation and invasive species being relatively more important. The principal actions carried out were habitat protection and management (75% of species), control of invasive species (50%), and captive breeding and release (33%). The 16 species represent only 8.9% of those currently classified as Critically Endangered, and 1.3% of those threatened with extinction. Many of these additional species slipped closer to extinction during 1994–2004, including 164 that deteriorated in status sufficiently to be uplisted to higher categories of extinction risk on the IUCN Red List (IUCN, 2006). Efforts need to be considerably scaled up to prevent many more extinctions in the coming decades. The knowledge and tools to achieve this are available, but we need to mobilize the resources and political will to apply them.

Quelea quelea (weaver bird).

2021 ◽  
Author(s):  
Robert Cheke
Keyword(s):  
Bird Species ◽  
Breeding Population ◽  
Sub Saharan Africa ◽  
Grain Crops ◽  
The World ◽  
Major Pest ◽  
Sub Saharan ◽  
Economical Losses

Abstract The red-billed quelea is a small weaver bird native to sub-Saharan Africa and renowned for its attacks on small-grain crops within Africa. It is the most numerous bird species in the world, with peak post-breeding population estimated at 1,500,000,000. The red-billed quelea is mainly granivorous, except when feeding its chicks insects or when eating insects prior to migration or breeding, and it relies on a supply of grass seeds to survive. When unable to find grass seeds or when opportunities arise, quelea will attack crops. It is a major pest throughout much of sub-Saharan Africa and can cause significant economical losses.

scholarly journals Population dynamics of five riverbed breeding bird species on the lower Drava River, NE Slovenia

Acrocephalus ◽  
2017 ◽  
Vol 38 (174-175) ◽  
pp. 85-126
Author(s):  
Luka Božič ◽  
Damijan Denac
Keyword(s):  
Population Dynamics ◽  
Bird Species ◽  
Breeding Population ◽  
Population Increase ◽  
General Situation ◽  
Breeding Bird ◽  
Main River Channel ◽  
Extreme Flood ◽  
Gravel Bars ◽  
Gravel Bar

AbstractIn 2006–2017, annual censuses of breeding bird species regarded as indicators of natural rivers were carried out on the 38.9 km long lowland stretch of the Drava riverbed between Maribor and Zavrč with altered flow regime due to the operating hydropower plants. Gravel bar habitats were surveyed in four years of the study period by combining orthophoto analysis and analysis of field photographs. Effects of gravel bar management were evaluated based at 20 locations. The Little Ringed PloverCharadrius dubiusoccurred on 39.8% of the gravel bars, but most were occupied only in a few years and held just one breeding pair. Low numbers between 2009 and 2012 (< 30 pairs) were followed by a steep population increase from 2014 onwards to a maximum of 66–73 pairs (1.7–1.9 p/km). Such population dynamics was attributed to the lack of large discharges (>500 m3/s) and consequent overgrowing of riverbed in the first part of the study period, while the increase in the second part was due to the creation of extensive shingle areas (from 20,6 ha in 2009/10 to 37,8 ha in 2014) by the extreme flood in early November 2012, subsequent regular occurrence of large discharges outside the breeding seasons and large-scale removals of woody vegetation. Breeding population of Common SandpiperActitis hypoleucosremained at a rather similar low level (<20 p) during most of the period studied after an initial decline, and did not reflect changes in the overall surface area of riverbed habitats. Contrary to the general situation, the number of breeding pairs on gravel bars subjected to management increased several-fold. Maximum number of pairs on these bars was reached up to four years after the initiation of management measures, as only then the optimal mosaic of early successional stages interspersed with shingle areas developed at main sites. The species was widespread only on lower part of the Drava. KingfisherAlcedo atthiswas fairly widely distributed along the riverbed, but occurred in rather low densities throughout (c. one pair on 2–3 km of the studied riverbed on average), probably as a result of limited bank erosion and consequent overgrowing/lack of suitable nest sites. The population was estimated as stable with effects of harsh winter conditions on breeding numbers in some years. The majority of nest holes were excavated in eroded river banks along the main river channel (77.8%), followed by similar sites located in mouth areas of small tributaries of the Drava (14.8%). Regular breeding of Sand MartinRiparia ripariasince 2012 (up to 259, mostly at only one location annually) was almost exclusively the result of the annual artificial nest site preparation programme. Fairly large gravel bar-breeding population of White WagtailMotacilla alba, monitored since 2013 and predominantly ground nesting in sparsely vegetated areas, seems unusual considering the prevalent breeding habits of the species at the European scale. Conservation implications and guidelines for future management efforts are discussed.

scholarly journals The Occurence of Ecological Traps in Bird Populations: Is our Knowledge Sufficient? A Review

2012 ◽  
Vol 5 (3) ◽  
pp. 36-56 ◽  
Author(s):  
Petr Suvorov ◽  
Jana Svobodová
Keyword(s):  
Exotic Species ◽  
Species Conservation ◽  
Habitat Type ◽  
Bird Species ◽  
Ecological Trap ◽  
Native Communities ◽  
Bird Populations ◽  
Suburban Areas ◽  
Arable Fields ◽  
Insufficient Time

ABSTRACT Anthropogenic changes in a landscape create new cues for birds, which must permanently adapt to these. If landscape changes occur too quickly, individuals have insufficient time to develop adequate reactions. They may, therefore, preferentially nest in low-quality habitats, which can lead to diminished nesting success and to reduction of their population size. This is usually termed the ecological trap hypothesis. We reviewed 38 studies investigating this phenomenon and analysed whether relationships exist between ecological trap occurrence and geographical region, habitat type, and/or life strategies of bird species. Ecological traps were most often associated with the presence of exotic species. Exotic species can modify environmental conditions in ways to which native communities are not adapted. They have been mainly detected in open habitats. Such open habitats as arable fields and meadows are under greater human pressure, and rapid changes probably occur there more frequently. Although more studies from North America were investigated, the hypothesis was supported more frequently in European studies. This is possibly due to higher human population density and, hence, more frequent habitat changes. Our results show that an ecological trap is not likely associated with migration. Ground nests suffered fewer consequences of such traps than did other nest types. Although the implications of the ecological trap hypothesis in species conservation are undisputable, a more detailed approach is still needed. For instance, some habitat types, such as suburban areas, have been neglected in the context of ecological traps, as has been the phenomenon’s appearance in pristine habitats.

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