scholarly journals Undesirable aliens: factors determining the distribution of three invasive bird species in Singapore

2003 ◽  
Vol 19 (6) ◽  
pp. 685-695 ◽  
Author(s):  
Haw Chuan Lim ◽  
Navjot S. Sodhi ◽  
Barry W. Brook ◽  
Malcom C. K. Soh

Biological invasions are a major environmental concern due to their negative impacts on biodiversity and economics. We determined the population sizes and habitat-abundance relationships of the three most successful invasive bird species in Singapore: the house crow Corvus splendens, white-vented myna Acridotheres javanicus and common myna A. tristis. Estimated population sizes of the three species between February 2000 and February 2001 were between 106 000-176 000, 122 000-155 000 and 20 000-29 000, respectively. Population size of the house crow grew dramatically (>30-fold) in the last 15-16 y while that of the white-vented and common myna declined. Habitat-abundance relationships suggest that house crows are highly dependent on anthropogenic food. Their abundance was also positively related to proximity to coast. The common myna associated closely with agricultural areas while the white-vented myna probably preferred urban greenery among residential buildings. Our study shows that the three invasive bird species associated with different aspects of human-modified environment.

1978 ◽  
Vol 26 (1) ◽  
pp. 39 ◽  
Author(s):  
HR Dang ◽  
SS Guraya

Testis growth and regression were studied, in relation to environmental temperature, sunshine, relative humidity and rainfall, in the house crow Corvus splendens, the common myna Acridotheres tristis and the house sparrow Passer domesticus, all of which are harmful species in the Punjab. Testis weight varied greatly during the year, but the species differed in their response to environmental conditions. The crow and the myna have active testes during May-July and April-July respectively; in the sparrow the testes are active twice in the year, February-June and September-October. The environmental factors are not sufficient to regulate the reproductive behaviour of these birds in the Punjab, and it is suggested that the reproductive state of birds is determined by a combination of exteroceptive and enteroceptive factors which varies considerably among species.


Biologia ◽  
2015 ◽  
Vol 70 (5) ◽  
Author(s):  
Filip Tulis ◽  
Michal Baláž ◽  
Ján Obuch ◽  
Karol Šotnár

AbstractOpportunistic predator like the long-eared owl is able to respond to population fluctuations of its main prey. The composition of the winter diet of this owl species was investigated during the period of 13 winters (1992-2000, 2006-2011) in agricultural areas in Slovakia. In total, we found 23 mammal species and 33 bird species (H′ = 0.82) in pellets. The frequency of the dominant prey species, the common vole, varied from 57.7% to 92.4%. Our data show that the abundance of the common vole: (i) had biggest impact on the food niche breadth of the long-eared owl; (ii) when in decline, it was significantly compensated by the increase in the amount of 15 other accessory species (subject to the specific diet offered during the study winters); (iii) was positively correlated with the number of owls in the winter-roost, which varied during the 13 studied winters.


Author(s):  
Bushra Aziz ◽  
Muhammad Zubair ◽  
Nausheen Irshad ◽  
Khawaja Shafique Ahmad ◽  
Majid Mahmood ◽  
...  

AbstractThe current study was designed to determine the concentrations of toxic metals (Ni, Pb and Cr) in feathers of birds collected from four regions of NE Pakistan. Feather samples of birds (House Crow, Common Myna and House Sparrow) were collected from different areas. Atomic absorption spectrophotometer was used to determine the concentration of metals in feathers. Analysis of the data revealed that concentrations of Pb and Cr were significantly different (p < 0.05) among bird species, whereas no difference (p > 0.05) was detected among bird species (house crow, common myna and house sparrow) for Ni. A significant difference was found for the concentration of Pb and Ni in all the four studied regions. Whereas, non-significant difference was found in all the studied regions for the concentrating of Cr. It was revealed that there is significant rising concentration of metals (Pb, Cr) in feathers of birds in Azad Kashmir.


2020 ◽  
Vol 27 (2) ◽  
pp. 142-145
Author(s):  
Seok-Jun Son ◽  
Jae-Pyoung Yu ◽  
In-Kyu Kim ◽  
Jung-Lea Kim ◽  
Jung-Hoon Kang

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 648
Author(s):  
Elizabeth Hewitt

In addition to formalized leadership roles within organizations, leadership can also influence members through informal channels. This work argues that multifamily residential buildings can be viewed as organizations and, as such, explores the influence that informal leaders can wield in shaping culture around the motivation for conserving energy. This work draws on qualitative fieldwork conducted in a Brooklyn cooperative building. Findings indicate that the study building benefitted from the leadership of a long-standing board member, which contributed to the implementation of a number of energy efficiency initiatives. Interestingly, this leadership also led to a culture of cost efficiency over environmental concern as the motivating force behind these initiatives. This narrative was well disseminated, with most residents reporting that the building does not have a culture of conservation, despite a strong energy efficiency leaning. Thus, this work posits that leadership can greatly shape perception and culture around energy but can also be leveraged to craft a more environmentally-motivated conservation culture. It also argues that leadership can be complementary to decentralized organizational structures, and that creative mechanisms in residential buildings can capitalize on both, allowing members at all levels of the organization more influence in shaping the building’s culture.


Oryx ◽  
2006 ◽  
Vol 40 (3) ◽  
pp. 266-278 ◽  
Author(s):  
Stuart H.M. Butchart ◽  
Alison J. Stattersfield ◽  
Nigel J. Collar

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.


2021 ◽  
Vol 48 (2) ◽  
pp. 441-456
Author(s):  
Ashikur Rahman Shome ◽  
Md Mahabub Alam ◽  
Md Fazle Rabbe ◽  
Mohammad Mijanur Rahman ◽  
Mohammad Firoj Jaman

A study on diversity, status, and habitat preference of avifauna was conducted from November 2017 to October 2018 in Magura Sadar upazila, Magura. Data was collected through direct field observations using line-transect method. Field surveys were made for three days per month in both rural and urban sites. A total of 140 species of birds belonged to 18 orders and 48 families were reported. Among the total species, 55% (77 species) were non-passerines and 45% (63 species) passerines with the highest individuals were counted under order Passeriformes. Resident bird species were dominant (106 species, 75.71%) over migratory (34 species, 24.28%) species. Species richness was the highest in the rural areas (124 species, 88.57%) and occurrence was the highest in winter season (97 species, 69.29%). The maximum species were recorded from trees (87 species, 62.14%) as preferred habitat. In this study, in total 4,060 individuals of birds were counted and among them, 51.55% (n=2093) were observed in the rural areas and 48.45% (n=1967) were in the urban areas. The highest number of birds was found in December (10.34%, n=432) and seasonal abundance was the highest in winter (40.15%, n=1630). Abundance was the highest for Common Myna (5.76%, n=234) among all recorded species. Diversity indices showed that the bird species were the most diverse in the rural areas in the winter season and in July. Habitat diversity indices were the highest for trees and birds used different types of habitats at different times for roosting, breeding and feeding. Regarding the observation status, 29.28% species was very common, 4.28% common, 31.42% fairly common, and 35% were few. This baseline data indicate that this study site is significant from the ecological and conservation point of views. Therefore, further research is necessary to understand how this avian diversity is maintained in this ecological setting. Bangladesh J. Zool. 48(2): 441-456, 2020


2016 ◽  
Author(s):  
Alexander Suh ◽  
Sandra Bachg ◽  
Stephen Donnellan ◽  
Leo Joseph ◽  
Jürgen Brosius ◽  
...  

AbstractPasseriformes (“perching birds” or passerines) make up more than half of all extant bird species. Here, we resolve their deep phylogenetic relationships using presence/absence patterns of short interspersed elements (SINEs), a group of retroposons which is abundant in mammalian genomes but considered largely inactive in avian genomes. The resultant retroposon-based phylogeny provides a powerful and independent corroboration of previous indications derived from sequence-based analyses. Notably, SINE activity began in the common ancestor of Eupasseres (passerines excl. the New Zealand wrens Acanthisittidae) and ceased before the rapid diversification of oscine passerines (songbirds). Furthermore, we find evidence for very recent SINE activity within suboscine passerines, following the emergence of a SINE via acquisition of a different tRNA head as we suggest through template switching. We propose that the early evolution of passerines was unusual among birds in that it was accompanied by activity of SINEs. Their genomic and transcriptomic impact warrants further study in the light of the massive diversification of passerines.


2015 ◽  
Vol 38 (1) ◽  
pp. 121-127
Author(s):  
S. Saavedra ◽  
◽  
A. Maraver ◽  
J. D. Anadón ◽  
J. L. Tella ◽  
...  

The common myna Acridotheres tristis is listed among the world’s 100 worst invasive alien species. We combined previous records with a field survey to update the extent and fate of myna introductions in Spain and Portugal. Results suggest that there have been at least 22 independent accidental introductions of three myna species throughout the Iberian peninsula and three archipelagos since the early 1990s. While bank mynas (A. ginginianus) did not become established elsewhere, common mynas reached breeding populations on four islands. Eradication efforts allowed the extirpation of these breeding island populations, but common mynas continue to breed in the Tagus Estuary (continental Portugal). In this region, there is also a breeding population of crested mynas (A. cristatellus), which was undergone an exponential population growth in the last decade. To avoid further accidental introductions, eradication campaigns should be combined with preventive actions aiming to stop the trade of these species in Europe.


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