scholarly journals Population size, dynamics and reproduction success of the lesser spotted eagle (Aquila pomarina) in Latvia

2015 ◽  
Vol 9 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Uģis Bergmanis ◽  
Ainārs Auniņš ◽  
Aivars Petriņš ◽  
Valdis Cīrulis ◽  
Jānis Granāts ◽  
...  

Abstract We analysed the population size, population dynamics and reproduction success of the lesser spotted eagle in Latvia from 1988 to 2014. While the overall population did not show a statistically significant trend during any of the periods analysed (long, medium and short term), the populations in the individual study areas changed differently: of five research plots, populations were stable in two, increased in one, and decreased in two research plots. Using the existing research plots as samples of breeding numbers in areas of different breeding density classes based on forest management units, the total breeding population in Latvia was estimated. The overall number of breeding pairs in 2012-2014 was between 3700-4000. During the period 1988-2014, 65.62% of all pairs recorded as present on their home range, made a breeding attempt and laid eggs. The reproductive success ratio was 0.49 young per occupied territory with an adult pair of birds and 0.74 young per breeding pair which laid eggs. Overall, during the 21 -year research period there was a stable long-term trend in reproductive success (young per pair present on home range). Rarely, indeed only in 1 .89% of all cases did two young fledge. The total number of young (young per 100 km2) shows stable long-, medium- and short-term trends with an average value of 5.1 young per 100 km2.

Ibis ◽  
2015 ◽  
Vol 157 (3) ◽  
pp. 601-613 ◽  
Author(s):  
Will J. Peach ◽  
John W. Mallord ◽  
Nancy Ockendon ◽  
Chris J. Orsman ◽  
William G. Haines

The Auk ◽  
1988 ◽  
Vol 105 (4) ◽  
pp. 649-662 ◽  
Author(s):  
Carlos A. Delannoy ◽  
Alexander Cruz

Abstract We studied the breeding biology of the Sharp-shinned Hawk (Accipiter striatus venator ) in Maricao forest of western Puerto Rico from 1978 to 1985. Sharp-shinned Hawks are year-round residents and establish nesting territories only during the breeding season, which coincides with the dry and beginning of the wet seasons. Nesting sites were occupied in December and January every year and reoccupancy rates were 50% or higher. Prolonged and intense territorial conflicts between mated and unmated males were common. The onset of egg-laying was in late March or early April approximately 3-4 months after occupancy of nesting sites. Laying of first clutches peaked in early April and spanned 38 days (n = 19 clutches). Laying of second clutches occurred irregularly and spanned 55 days (n = 8 clutches). Females renested only after the initial clutch or brood was lost. The incubation period was 32 days (n = 13 clutches), similar to the duration reported in temperate North America. Nestling females attained larger asymptotic mass than males, but the latter grew faster; although the slopes of the regression lines were statistically homogeneous. Males fledged at an average age of 28.2 days and females at 32.1 days. Young were slightly heavier than adults at fledging, but the wing chord and tail lengths were approximately 50% shorter than those of adults. Fledging occurred at the peak of prey abundance. The breeding cycle in Puerto Rico was approximately 2 months longer than that recorded in Oregon and Utah. The time that elapsed from occupancy of nesting sites to egg laying accounted for the differences. Juveniles departed from nesting sites when prey was still abundant but delivery rates had declined considerably. A total of 105 eggs was laid in 40 nests (average clutch size 2.6), of which 63% hatched and 47% of the nestlings fledged. A total of 0.8 young fledged per breeding attempt. Overall nest success was 29%, 36% (n = 33 nests) in first nesting attempts and 0% in second nesting attempts (n = 9 nests). Most reproductive losses in 28 nests resulted from nestling mortality from Philornis sp. (Diptera, Muscidae) (n = 9) and desertion of clutches (n = 11). Fecundity and reproductive success was lower in Puerto Rico than in Oregon, Utah, and Wyoming. Despite low reproductive success in Maricao forest, the breeding population did not decline during our study.


2006 ◽  
Vol 55 (1-6) ◽  
pp. 13-19 ◽  
Author(s):  
H. Li ◽  
D. Lindgren

Abstract A breeding program was simulated in this study. Two alternative ways of selecting the breeding population for the following generation was compared. Phenotypic selection, which means to select just on the individual performance, and combined index selection, which means selection on predicted breeding value for each individual obtained by weighting family average and individual phenotype, were compared. The plant number (testing resource) and gene diversity (status number, Ns) were kept constant, but the breeding population size was variable and chosen for maximizing gain for the particular breeding scenario. At low and medium heritability phenotypic selection was inferior to combined index selection. Only when heritability was high phenotypic selection was as efficient (generation 1) as or more efficient (generation 5) than combined index selection. This contrasts to earlier studies done under constant breeding population size, where selection methods appeared similar. The advantage in gain of combined index selection is usually at a larger breeding population size. At limited heritability and breeding population size the difference is considerable. When breeding population size was kept rather small (<100), and the heritability limited, combined index selection can result in slightly higher gain than phenotypic selection at the same gene diversity, but this was at the cost of a much larger breeding population. Phenotypic selection and combined index selection appears as rather similar for many cases in this simple model used in this study. Considering other advantages with phenotypic selection, it may often be regarded as a competitive alternative.


2014 ◽  
Vol 24 (4) ◽  
pp. 466-476 ◽  
Author(s):  
ERICA C. PACÍFICO ◽  
EDUARDO A. BARBOSA ◽  
THIAGO FILADELFO ◽  
KLEBER G. OLIVEIRA ◽  
LUÍS F. SILVEIRA ◽  
...  

SummaryLear’s Macaw Anodorhynchus leari is currently listed as “Endangered” by IUCN. Although it only breeds on cliffs at two protected sites in Bahia State, Brazil, there is no accurate information on population parameters such as the number of breeding pairs and their breeding performance. Between 2009 and 2010, we sought to quantify, for the first time, breeding population size and the main breeding parameters for the species in the two known breeding sites, by quantifying the number of active nests and monitoring 75 breeding attempts. Overall, 80% of the breeding attempts were successful with 1.33 (± 0.86 SD) fledglings/breeding attempt (productivity) and 1.67 (± 0.60 SD) fledglings/successful nest (brood size). Breeding success and productivity were higher in 2010, while brood size did not vary between years and breeding sites. By adding 73 estimated nests to the 41 nests monitored, 228 individuals were estimated to be reproductively active in 2010, representing c.20% of the population (1,125 individuals). Given that the species is confined to a single population, further population increases could provoke overcrowding and negative density-dependent effects if it does not expand geographically. Therefore, long-term population monitoring focusing on the fraction of the population that is actually breeding and its breeding performance, rather than solely on the whole population size, is important for a better understanding of the population dynamics and conservation of this species.


2017 ◽  
Vol 28 (1) ◽  
pp. 38-58
Author(s):  
NINA SEIFERT ◽  
COSIMA TEGETMEYER ◽  
ANGELA SCHMITZ ORNÉS

SummaryKnowledge of a species’ ecological requirements is a prerequisite for effective conservation, particularly if the species is assumed to be declining due to modification of its primary habitats. Information about habitat suitability allows both the inference of specific habitat management measures as well as population size estimates which can facilitate the setting up of conservation priorities. As one of the least known Palaearctic breeding birds, the current knowledge of Baillon’s Crake Zapornia pusilla comprises only very general information about the species’ ecological requirements, habitat selection, extent and dynamics of home ranges or population densities within its Palaearctic-Afrotropical range. We used a multi-scale approach to assess the species’ habitat requirements in the Senegal River Delta, north-west Senegal. At the individual level, we calculated Manly selection indices for 17 radio-tracked Baillon’s Crakes, allowing for different levels of resource availability. Considering the entire Djoudj area including the Parc National des Oiseaux du Djoudj (PNOD), we modelled presence probability as well as population density of Baillon’s Crakes based on high-resolution satellite images and capture data from field surveys in 2009–2013. Using 95% kernels, home range size was on average 1.77 ± 0.86 ha with significant differences between habitats. Both at the individual as well as population level, Baillon’s Crakes preferred edge structures, selecting for trampling paths and edges along open water bodies as well as boundaries of specific vegetation stands while species composition was of less importance. Based on the regression models, we identified 9,516 ha of suitable habitat within the Djoudj area and a potential population size of 10,714 individuals (range 3,146–17,408). Although global population estimates are highly tentative, we assume the Senegal River Delta and the PNOD of outstanding significance for African and possibly also European populations of Baillon’s Crake.


Author(s):  
O. Yu. Atkov ◽  
S. G. Gorokhova

The individual dynamics of the allostatic load index was revealed mainly due to changes in the glucose level, body mass index, which makes it applicable for assessing the short-term adaptation to the stay in the conditions of shift work


2021 ◽  
Vol 13 (6) ◽  
pp. 3319
Author(s):  
Chulin Pan ◽  
Huayi Wang ◽  
Hongpeng Guo ◽  
Hong Pan

This study focuses on the impact of population structure changes on carbon emissions in China from 1995 to 2018. This paper constructs the multiple regression model and uses the ridge regression to analyze the relationship between population structure changes and carbon emissions from four aspects: population size, population age structure, population consumption structure, and population employment structure. The results showed that these four variables all had a significant impact on carbon emissions in China. The ridge regression analysis confirmed that the population size, population age structure, and population employment structure promoted the increase in carbon emissions, and their contribution ratios were 3.316%, 2.468%, 1.280%, respectively. However, the influence of population consumption structure (−0.667%) on carbon emissions was negative. The results showed that the population size had the greatest impact on carbon emissions, which was the main driving factor of carbon emissions in China. Chinese population will bring huge pressure on the environment and resources in the future. Therefore, based on the comprehensive analysis, implementing the one-child policy will help slow down China’s population growth, control the number of populations, optimize the population structure, so as to reduce carbon emissions. In terms of employment structure and consumption structure, we should strengthen policy guidance and market incentives, raising people’s low-carbon awareness, optimizing energy-consumption structure, improving energy efficiency, so as to effectively control China’s carbon emissions.


Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 663
Author(s):  
Kui-Hai Pang ◽  
Amanda K. Rowe ◽  
Lori K. Sheeran ◽  
Dong-Po Xia ◽  
Lixing Sun ◽  
...  

Male nonhuman primate sexual interference, which includes copulation interruption and copulation harassment, has been related to reproductive success, but its significance has been challenging to test. Copulation interruption results in the termination of a copulation before ejaculation, whereas copulation harassment does not. We conducted this study using the all-occurrence behavior sampling method on sexual interference behaviors of seven adult and four subadult male Tibetan macaques (Macaca thibetana) in mating and non-mating seasons at Mt. Huangshan, China, from August 2016 to May 2017. Our results showed that males’ individual proportion of copulation interruption and harassment was higher during the mating season than during the non-mating season. In addition, dominant males more often performed interruption, whereas subordinate males more often performed harassment. We found no difference in the individual proportion of copulation interruption or harassment between adult and subadult males. Adult and subadult males both directed copulation interruption and harassment more often toward the mating male than toward the mating female. Lastly, the post-ejaculation phase of copulation was shorter when copulation harassment occurred than when it did not. Our results suggest that sexual interference may be an important mating tactic that adult and subadult males use in male–male sexual competition.


Human Affairs ◽  
2013 ◽  
Vol 23 (3) ◽  
Author(s):  
Miroslav Popper

AbstractThe article approaches the topic of social trust from an evolutionary perspective. It begins by summarising the most influential approaches that have defined specific and social trust and ascertains what causes differences in degrees of trust and how the potential risk of deception might be lowered. It then notes that the basis of morality had already been formed during the era of prehistoric man, who was able to create coalitions against aggressors and to socially control the behaviour of deviants. It points out, however, that having a certain predisposition to behaving cooperatively or an increased sensitivity to recognising and not tolerating behaviour aimed at abusing cooperation is not a sufficient guarantee of the fact that people will always (or at least in the majority of situations) favour cooperation over deception. One of the reasons for this is a tendency to favour short-term gains over long-term ones. The article argues that establishing norms (moral, social and legal) produces a higher level of social trust because it not only “encourages” individuals to behave in certain ways in particular situations but also works as a sanction which “discourages” the individual from socially deviant behaviour. The article then focuses on a debate about the causal relationship between social trust and social capital. It discusses the suggestion that political institutions, government and the judiciary may reduce rather than raise levels of social capital and consequently also the level of social trust. This is partly because of their powerful position and the consequent scope for corruption and partly because of the fact that even when attempting to act honestly, representatives of these institutions cannot sufficiently reflect upon dynamic change at the local level. Finally, the article ends by adopting the position that social trust is built primarily from bottom up and so it is risky to continually doubt the very existence and usefulness of social norms and morality and to be governed simply by legal norms.


2021 ◽  
pp. 68-70
Author(s):  
Nitin Hiraman Suryawanshi ◽  
Amit Aggarwal ◽  
Abhijit Kadam

A study of stroke in young patients has recently become a subject of interest. This is due to a lot of impact on the individual and society. Study of stroke in young patients can lead to therapeutical results affecting both short term and long-term outcomes. Our study is hospital based retrospective study for duration of 1 year. Thi Methods: Results: s study revealed stroke in young in 25.16% of all stroke cases, with cerebral infarction in 56% and followed by intracerebral haemorrhage in 25.64%, and cerebral venous thrombosis in 18%. The most common presenting symptom was hemiparesis. The most prevalent risk factor for stroke in young was hypertension followed by diabetes mellitus, alcohol consumption and smoking. Stroke in young requires a differe Conclusion: nt approach to investigate and treat. This is due to different underlying etilogy as compared to elderly. Although traditional risk factors are associated with stroke, behavioural pattern such as smoking and alcohol may cause and promote development of stroke in young.


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