scholarly journals Great bustards Otis tarda in Morocco: status in spring 1999 and evidence of a decline in recent decades

Oryx ◽  
2000 ◽  
Vol 34 (2) ◽  
pp. 141-146
Author(s):  
Juan C. Alonso ◽  
Simon J. Lane ◽  
Robert Dawson ◽  
Youssef Idaghdour
Keyword(s):  
Sex Ratio ◽  
Adult Males ◽  
Great Bustard ◽  
Range Contraction ◽  
Otis Tarda ◽  
Conservation Measures ◽  
Western Morocco ◽  
North Western

AbstractA spring (1999) census was conducted of great bustards Otis tarda in north-western Morocco, where a poorly known population of this species occurs. Sixty-four birds were seen in four distinct areas. Adult males were seen displaying at three of these areas, indicating that they are probably traditional lek sites. No adult males were observed in the fourth area and its status as a lek site is uncertain. Two further sites were visited but no birds were seen. Two lst-year males were seen with their mothers, demonstrating successful breeding in 1998. We argue that the small number of birds, a population sex ratio of 1:3.3 in favour of females, evidence for a range contraction, and probable isolation from other great bustard populations mean that this population is now extremely endangered and will decline to extinction unless conservation measures are implemented immediately.

scholarly journals Underground cabling and marking of power lines: conservation measures rapidly reduced mortality of West-Pannonian Great Bustards Otis tarda

2011 ◽  
Vol 22 (3) ◽  
pp. 299-306 ◽  
Author(s):  
RAINER RAAB ◽  
CLAUDIA SCHÜTZ ◽  
PÉTER SPAKOVSZKY ◽  
EIKE JULIUS ◽  
CHRISTIAN H. SCHULZE
Keyword(s):  
Mortality Rate ◽  
Linear Models ◽  
Power Line ◽  
Distribution Range ◽  
Power Lines ◽  
Mortality Factor ◽  
Great Bustard ◽  
The West ◽  
Otis Tarda ◽  
Conservation Measures

SummaryCollisions with power lines represent an important mortality factor for Great Bustards Otis tarda throughout the distribution range of the species. This study evaluates the success of two conservation measures implemented in the West-Pannonian distribution range to reduce the number of power line collision casualties: (1) extensive underground cabling of 43.1 km power lines, and (2) marking of 89.7 km power lines starting in 2005 and 2006, respectively. The mortality rate of Great Bustards in our study area (covering 686.5 km2) decreased significantly between 2002 and 2011, predominantly caused by reduced mortality due to power line collisions. Univariate tests indicate that underground cabling and power line marking significantly decreased power line collision casualties. Generalised linear models (GLMs) highlighted the prominent effect of underground cabling. Our results indicate that five years after underground cabling and marking of power lines within core areas of the West-Pannonian distribution range of the Great Bustard, the population already benefited through a significantly decreased mortality rate. Both conservation measures most likely contributed strongly to the rapid recovery of the West-Pannonian Great Bustard population observed within the last decade.

scholarly journals Recent status and population decline of the Great Bustard Otis tarda in Iran

2015 ◽  
Vol 25 (3) ◽  
pp. 377-384 ◽  
Author(s):  
AHMAD BARATI ◽  
RAHIM ABDULKARIMI ◽  
JUAN CARLOS ALONSO
Keyword(s):  
Literature Review ◽  
Current Distribution ◽  
Population Decline ◽  
Population Trends ◽  
Great Bustard ◽  
Otis Tarda ◽  
Conservation Measures ◽  
Marked Decline

SummaryThe current distribution and recent population trends of the Great Bustard (Otis tarda) in Iran were investigated based on a literature review and unpublished data (1995–2008) followed by three years of census (2009–2011) in areas where the species is still breeding. Results suggest that Great Bustards have disappeared from a large part of their former distribution in the country, including East Azarbayjan, Hamedan and Kurdistan provinces. The surviving groups are concentrated in West Azarbayjan where numbers are rapidly declining. The present population is estimated at about 43–48 birds in 2011, confirming a marked decline compared to the 200–300 birds estimated in the early 1990s. About 80–90% of the extant birds are concentrated in the plains of Boukan. Strict conservation measures are urgently needed to prevent the extinction of this species in Iran.

The Probable Strong Decline of the Great Bustard Otis tarda tarda Population in North-Western China

Ardeola ◽  
2018 ◽  
Vol 65 (2) ◽  
pp. 291
Author(s):  
Muyang Wang ◽  
Manuel Antonio González ◽  
Weikang Yang ◽  
Peter Neuhaus ◽  
Beatriz Blanco-Fontao ◽  
...  
Keyword(s):  
Western China ◽  
Great Bustard ◽  
Otis Tarda ◽  
North Western

Great Bustard (Otis tarda)

2020 ◽  
Author(s):  
Nigel Collar ◽  
Ernest Garcia
Keyword(s):  
Great Bustard ◽  
Otis Tarda

scholarly journals Nesting, Sex Ratio and Natural Enemies of the Giant Resin Bee in Relation to Native Species in Europe

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 545
Author(s):  
Sara Straffon Díaz ◽  
Luca Carisio ◽  
Aulo Manino ◽  
Paolo Biella ◽  
Marco Porporato
Keyword(s):  
Sex Ratio ◽  
Natural Enemies ◽  
Native Species ◽  
Wild Bees ◽  
Trap Nests ◽  
Native Bee ◽  
New Locations ◽  
Negative Impacts ◽  
Set Up ◽  
North Western

Megachile sculpturalis (Smith, 1853) is the first exotic bee species in Europe. Its remarkably fast expansion across this continent is leading to a growing concern on the extent of negative impacts to the native fauna. To evaluate the interactions of exotic bees with local wild bees, we set up trap nests for above-ground nesting bees on a semi-urban area of north-western Italy. We aimed to investigate the interaction in artificial traps between the exotic and native wild bees and to assess offspring traits accounting for exotic bee fitness: progeny sex ratio and incidence of natural enemies. We found that the tunnels occupied by exotic bees were already cohabited by O. cornuta, and thus the cells of later nesting alien bees may block the native bee emergence for the next year. The progeny sex ratio of M. sculpturalis was strongly unbalanced toward males, indicating a temporary adverse population trend in the local invaded area. In addition, we documented the presence of three native natural enemies affecting the brood of the exotic bee. Our results bring out new insights on how the M. sculpturalis indirectly competes with native species and on its performance in new locations.

Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz
Keyword(s):  
Sex Ratio ◽  
Ringed Seal ◽  
Adult Males ◽  
Population Parameters ◽  
Phoca Hispida ◽  
Age Class ◽  
Ringed Seals ◽  
Males And Females ◽  
The Mean ◽  
Sexually Mature

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.

scholarly journals Key Mortality Causes of the Great Bustard (Otis Tarda) in Central Hungary: An Analysis of Known Fatalities

2015 ◽  
Vol 22 (2) ◽  
pp. 32-41 ◽  
Author(s):  
Csaba Vadász ◽  
Miklós Lóránt
Keyword(s):  
Data Collection ◽  
Anthropogenic Factors ◽  
Relative Importance ◽  
Great Bustard ◽  
Systematic Data ◽  
Otis Tarda ◽  
Negative Effect ◽  
Breeding Attempt ◽  
Mortality Causes ◽  
Systematic Data Collection

Abstract In this study, we identified the key mortality causes of eggs, juveniles and adults of the Great Bustard (Otis tarda) and quantified the relative importance of those, based on systematic data collection that have been carried out during the period between 2005 and 2014 at the Upper-Kiskunság region in Central Hungary. Rate of mortality regarding juveniles and adults was 39.71% caused by anthropogenic factors. Within the anthropogenic factors leading to mortality, collision was represented by 81.48% of fatalities, whereas mowing/hay making represented by 18.52%. Hay making/mowing was the factor leading to unsuccessful breeding attempt with the strongest negative effect on the breeding success of the investigated population of the Great Bustard, as it was represented by 50.96% of all known mortality cases. Chemical treatment had the factor with the second strongest effect, as it was represented by 12.33% of all known mortality cases. The rate of unsuccessful breeding (hatching) caused by particular activities (hay making/mowing, tillage, harvesting) varied between 68.42% and 75.00%. It was the disturbance by passers-by which led to the highest portion of unsuccessful breeding with 83.33% unsuccessful nests.

Genetic structure and population history of wintering Asian Great Bustard (Otis tarda dybowskii) in China: implications for conservation

2017 ◽  
Vol 158 (3) ◽  
pp. 761-772 ◽  
Author(s):  
Gang Liu ◽  
Xiaolong Hu ◽  
Aaron B. A. Shafer ◽  
Minghao Gong ◽  
Morigen Han ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Population History ◽  
Great Bustard ◽  
Otis Tarda ◽  
History Of

Contribution of adult sex ratio to trauma and reproductive output in large breeding groups of rhesus macaques (Macaca mulatta)

2021 ◽  
Vol 30 (4) ◽  
pp. 479-492
Author(s):  
J Crast ◽  
MA Bloomsmith ◽  
CM Remillard ◽  
T Meeker
Keyword(s):  
Sex Ratio ◽  
Macaca Mulatta ◽  
Social Dynamics ◽  
Rhesus Macaques ◽  
Well Being ◽  
Primate Research ◽  
Adult Males ◽  
Adult Sex Ratio ◽  
Breeding Groups ◽  
Financial Burdens

Maintaining stable breeding groups of rhesus macaques (Macaca mulatta) can be challenging due to the complex social dynamics and despotic nature of the species. Trauma from aggression is a common problem in rhesus colonies and can cause social disruption, strain veterinary and animal management resources, and potentially affect reproduction. Previous research has shown that increasing the number of non-natal adult males in a breeding group can improve group stability, reduce trauma, and increase reproduction. Here, we used mixed-effects regression models to examine the effects of sex ratio and other factors on trauma and reproduction at the Yerkes National Primate Research Center using a historical dataset made up of four large rhesus groups over an eleven-year period (2003–2013). As expected, sex ratio was a significant predictor for both trauma and reproduction. However, group age since formation was a stronger predictor of trauma frequency and the amount of space available was a slightly better predictor of reproduction than sex ratio or trauma. These results indicate that improving sex ratios can be a viable management strategy to reduce trauma and improve reproduction, particularly when it is difficult to manipulate the group compositions and/or their housing situations. Reducing trauma is a primary goal for rhesus breeding colonies, as it directly impacts the monkeys' health and psychological well-being. Such improvements are necessary for the ethical treatment and care of the animals themselves, but also to reduce financial burdens and maintain a healthy colony for research purposes.

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