scholarly journals Reproductive Success of American Kestrels: The Role of Prey Abundance and Weather

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 814-822 ◽  
Author(s):  
Russell D. Dawson ◽  
Gary R. Bortolotti
Keyword(s):  
Reproductive Success ◽  
Natural Variation ◽  
Weather Conditions ◽  
Prey Abundance ◽  
Offspring Size ◽  
Minimum Threshold ◽  
Provisioning Behavior ◽  
American Kestrels ◽  
Parental Provisioning

Abstract We investigated how natural variation in abundance and availability of the main prey of American Kestrels (Falco sparverius), small mammals, influenced provisioning rates by parents, and offspring size and survival. Provisioning behavior of kestrels was not constrained by the abundance of food in the environment; however, the availability of food, mediated through variation in weather, appeared to significantly influence parental provisioning behavior. Moreover, variation in weather had clear effects on reproductive success because nestlings exposed to inclement weather were smaller and lighter at fledging, and less likely to survive to fledging, compared to nestlings raised during good weather conditions. Prey abundance was not related to offspring size or survival. Our results suggest American Kestrels are limited by the availability, as opposed to abundance, of food on territories. It is likely that during our study, prey abundance was above some minimum threshold necessary to support successful reproduction, and so variation in weather affected reproduction more than variation in prey abundance.

scholarly journals Evolution and expansion of the RUNX2 QA repeat corresponds with the emergence of vertebrate complexity

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Axel H. Newton ◽  
Andrew J. Pask
Keyword(s):  
Natural Variation ◽  
Skeletal Development ◽  
Skull Shape ◽  
Morphological Novelty ◽  
Transactivation Potential ◽  
Repeat Domain ◽  
Related Transcription Factor ◽  
Mammalian Skull ◽  
Evolutionary Tuning

AbstractRunt-related transcription factor 2 (RUNX2) is critical for the development of the vertebrate bony skeleton. Unlike other RUNX family members, RUNX2 possesses a variable poly-glutamine, poly-alanine (QA) repeat domain. Natural variation within this repeat is able to alter the transactivation potential of RUNX2, acting as an evolutionary ‘tuning knob’ suggested to influence mammalian skull shape. However, the broader role of the RUNX2 QA repeat throughout vertebrate evolution is unknown. In this perspective, we examine the role of the RUNX2 QA repeat during skeletal development and discuss how its emergence and expansion may have facilitated the evolution of morphological novelty in vertebrates.

scholarly journals Weather conditions explain reproductive success and advancement of the breeding season in Western Capercaillie ( Tetrao urogallus )

Ibis ◽  
2021 ◽  
Author(s):  
Joy Coppes ◽  
Jim‐Lino Kämmerle ◽  
Karl‐Eugen Schroth ◽  
Veronika Braunisch ◽  
Rudi Suchant
Keyword(s):  
Reproductive Success ◽  
Breeding Season ◽  
Weather Conditions ◽  
Tetrao Urogallus

Carotenoid-based plumage colouration in red bishops (Euplectes orix) — signalling presence rather than quality?

Behaviour ◽  
2011 ◽  
Vol 148 (11-13) ◽  
pp. 1372-1392 ◽  
Author(s):  
Alice U. Edler ◽  
Thomas W.P. Friedl
Keyword(s):  
Reproductive Success ◽  
Parasite Load ◽  
Blood Parasite ◽  
Male Reproductive Success ◽  
Sexually Dimorphic ◽  
Male Quality ◽  
Plumage Colouration ◽  
Selection For ◽  
Breeding Plumage

AbstractThe role of bright plumage colouration for female choice has been the focus of research in sexual selection for many years, with several studies showing that females prefer the most elaborately ornamented males, which are often also the highest quality individuals. Here, we analysed the associations between reproductive performance and plumage, body condition and blood parasite load in the red bishop (Euplectes orix), a sexually dimorphic and polygynous weaverbird species, where males in a carotenoid-based orange-to-red breeding plumage defend territories and build many nests to which they try to attract females. Male reproductive success in terms of number of nests accepted was mainly determined by the number of nests built, but was also positively related to blood parasite load, while we found no influence of plumage characteristics. Together with previously obtained data, our results indicate that plumage characteristics in the red bishop do not affect male reproductive success and are generally not suitable to reliably indicate male quality. We suggest that the primary function of the brilliant orange-scarlet breeding plumage might be presence signalling in terms of increasing conspicuousness of breeding males to females searching for mates.

scholarly journals Production choices with water markets and risk aversion: the role of initial allocations and forward trading

2018 ◽  
Vol 46 (4) ◽  
pp. 579-608 ◽  
Author(s):  
Philippe Bontems ◽  
Céline Nauges
Keyword(s):  
Irrigation Water ◽  
Weather Conditions ◽  
Water Markets ◽  
Initial Water ◽  
Production Risk ◽  
Net Returns ◽  
Murray Darling Basin ◽  
Forward Trading ◽  
Allocation Decisions

Abstract We develop a theoretical model that describes risk-averse farmers’ decisions when facing production risk due to uncertain weather conditions and when irrigation water can be traded on a market. We focus on the role of initial water allocations granted to irrigated farms at the start of the season. The presence of water markets makes the future water price uncertain and hence the value of initial water allocations uncertain. We analyse the properties of this background risk and study how initial water allocations impact farmers’ land allocation decisions between an irrigated crop and a non-irrigated crop, both characterised by random expected net returns. We then extend the model by permitting irrigation water to be traded ex-ante at a known price (forward market). Finally, we illustrate our main theoretical findings using simulations. We calibrate distributions of the random variables based on observed data from the Murray–Darling Basin in Australia where a water market has been in place for several decades.

The role of short-term weather conditions in temporal dynamics of fire regime features in mainland Spain

2019 ◽  
Vol 241 ◽  
pp. 575-586 ◽  
Author(s):  
Adrián Jiménez-Ruano ◽  
Marcos Rodrigues Mimbrero ◽  
W. Matt Jolly ◽  
Juan de la Riva Fernández
Keyword(s):  
Temporal Dynamics ◽  
Fire Regime ◽  
Weather Conditions ◽  
Short Term

scholarly journals Iridescent structural colour production in male blue-black grassquit feather barbules: the role of keratin and melanin

2009 ◽  
Vol 6 (suppl_2) ◽  
Author(s):  
Rafael Maia ◽  
João Victor O Caetano ◽  
Sônia N Báo ◽  
Regina H Macedo
Keyword(s):  
Thin Film ◽  
Natural Variation ◽  
Single Layer ◽  
Coherent Scattering ◽  
Interspecific Variation ◽  
Stray Light ◽  
Main Role ◽  
Minimum Number ◽  
Keratin Layer

Iridescent coloration plays an important role in the visual communication system of many animal taxa. It is known that iridescent structural colours result from layers of materials with different refractive indexes, which in feathers usually are keratin, melanin and air. However, the role of these materials in the production of structural iridescent coloration is still poorly documented. Despite the great interspecific variation in the organization of such structures in bird plumage, melanin layers are usually considered too opaque, suggesting its main role is to delineate the outermost keratin layer and absorb incoherently scattered stray light. We combined spectrometry, electron microscopy and thin-film optical modelling to describe the UV-reflecting iridescent colour of feather barbules of male blue-black grassquits ( Volatinia jacarina ), characterized by a keratin layer overlying a single melanin layer. Our models indicate that both the keratin and the melanin layers are essential for production of the observed colour, influencing the coherent scattering of light. The melanin layer in some barbules may be thin enough to allow interaction with the underlying keratin; however, individuals usually have, on an average, the minimum number of granules that optimizes absorbance by this layer. Also, we show that altering optical properties of the materials resulted in better-fitting models relative to the empirically measured spectra. These results add to previous findings concerning the influence of melanin in single-layer iridescence, and stress the importance of considering natural variation when characterizing such photonic structures.

scholarly journals Sex differences in helping effort reveal the effect of future reproduction on cooperative behaviour in birds

2018 ◽  
Vol 285 (1885) ◽  
pp. 20181164 ◽  
Author(s):  
Philip A. Downing ◽  
Ashleigh S. Griffin ◽  
Charlie K. Cornwallis
Keyword(s):  
Sex Differences ◽  
Reproductive Success ◽  
Kin Selection ◽  
Cooperative Behaviour ◽  
The Future ◽  
Helping Behaviour ◽  
Future Reproduction ◽  
Selection For ◽  
Family Groups

The evolution of helping behaviour in species that breed cooperatively in family groups is typically attributed to kin selection alone. However, in many species, helpers go on to inherit breeding positions in their natal groups, but the extent to which this contributes to selection for helping is unclear as the future reproductive success of helpers is often unknown. To quantify the role of future reproduction in the evolution of helping, we compared the helping effort of female and male retained offspring across cooperative birds. The kin selected benefits of helping are equivalent between female and male helpers—they are equally related to the younger siblings they help raise—but the future reproductive benefits of helping differ because of sex differences in the likelihood of breeding in the natal group. We found that the sex which is more likely to breed in its natal group invests more in helping, suggesting that in addition to kin selection, helping in family groups is shaped by future reproduction.

scholarly journals Rainfall and weather conditions inducing intense landslide activity in northern Spain (Deba, Guipúzcoa)

2020 ◽  
Author(s):  
Victoria Rivas ◽  
Juan Remondo ◽  
Jaime Bonachea ◽  
Javier Sánchez-Espeso
Keyword(s):  
Weather Conditions ◽  
Rainfall Threshold ◽  
Large Network ◽  
Antecedent Rainfall ◽  
Northern Spain ◽  
Rainfall Events ◽  
Landslide Activity ◽  
Long Time ◽  
Span 60

Abstract. The Deba area is intensely affected by frequent shallow landslides triggered by rainfall. Relationships between rainfall and landslides in northern Spain, particularly for rainfall events driving multiple movements simultaneously, have not been explored in depth so far. This contribution explores the role of rainfall in landslide activity during a quite long time span, (60 years), from a large network of rainfall gauges and a complete inventory of landslides, and utilizing three different strategies of analysis. 1,180 landslides have been inventoried, and 3,241 rainfall episodes automatically recognized and characterized in terms of rainfall amount, duration and intensity. Antecedent rainfall has also been considered. Six episodes of intense rainfall, which have produced multiple landslides (> 50 % of the recent past occurrences) have been identified. The analysis provides different results: the extraordinary character of the triggering rainfall has been assessed, the meteorological conditions associated to those extreme episodes have been recognized and empirical rainfall threshold producing multiple landslides has been found (I = 7.7D-0.428) and compared with others described in literature. Results show that multiple landslide occurrences are triggered by extreme convective rainfall, intense, short and with limited horizontal extent, as well as a marked summer-autumn seasonality, characteristic of Mediterranean climate.

scholarly journals KENYAMANAN IKLIM LOKASI WISATA BERBASIS ALAM DI KAWASAN TROPIS

Agromet ◽  
2019 ◽  
Vol 33 (2) ◽  
pp. 53-61
Author(s):  
Nofi Yendri Sudiar
Keyword(s):  
Weather Conditions ◽  
Education Level ◽  
Tourism Industry ◽  
Botanical Gardens ◽  
Visitor Perceptions ◽  
Survey Results ◽  
Climate Comfort ◽  
Selection Of

This research reveals visitors perceptions of climate comfort in nature-based tourism areas in Ecopark Ancol, Bogor Botanical Gardens (KRB) and Cibodas Botanical Gardens (KRC). In addition to calculating the comfort score using the TCI and HCI methods and modifying their thermal aspects, a survey was also carried out in all three tourism areas simultaneously. The survey was conducted to collect data on climate comfort perceptions and the role of the weather on these comfort. A total of 793 respondents participated in this study. The majority of visitors stated that the weather affected the comfort of the climate during the tour. But weather conditions do not fully influence decisions in the selection of tourist visits. The level of perceived climate comfort for the three tourism sites namely Ecopark was perceived as neutral (57.3%), KRB was perceived as comfortable (60%) and KRC was perceived as comfortable (78.4%). While based on the score calculation approaching the survey results in Ecopark is TCI index modified in its thermal aspect with PET Tianjin (57.2). KRB is HCI without modification (59) and KRC is HCI modified by its thermal aspect with PET Tianjin (77.6). Statistically there are significant differences between sex, age, education level and topography. By understanding visitor perceptions, strategies and appropriate actions can be developed to increase comfort in the nature-based tourism industry.

scholarly journals The role of organic farming in the formation of the harvest and the nutrition value of potatoes on unused arable lands and fallow lands of Altay Region (Western Siberia)

2017 ◽  
Vol 7 (4) ◽  
pp. 388-392
Author(s):  
D. A. Durnikin ◽  
O. Y. Voronkova ◽  
V. A. Kundius ◽  
L. I. Petrova
Keyword(s):  
Organic Farming ◽  
Western Siberia ◽  
Comprehensive Evaluation ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Mineral Fertilizers ◽  
Pests And Diseases ◽  
Altai Region ◽  
Fallow Lands

<p>In the article, a comprehensive evaluation of the role of organic farming in the formation of the crop and the nutritional value of perspective varieties cultivated within the climatic zone of Western Siberia is considered. The most favorable conditions for growing potatoes in the Altai Region of the Western Siberia are compared with other regions of Russia and those of foreign countries.<br />In the southern and southeastern regions of the Altai region, where the formation of tubers coincides with the hot period of the first half of summer, the high soil temperature negatively affects the eyes of the tubers. Therefore, the seed material here rapidly degenerates. To avoid this, summer potatoes are planted. Irrigation ensures high and stable potato yields irrespective of weather conditions. Moisture content of soil during the period from planting potatoes to shoots should be maintained at the level of 65-70 per cent, in the budding and flowering phases - of 75-85 per cent and during the period from the beginning of wilting of potato tops – of 60-65 per cent. The number of irrigations, their terms and standards, are determined by taking into account soil-climatic conditions, the phase of plant development and the application area of a crop.<br />The most effective irrigation method is sprinkling. The irrigation norm ranges from 500 to 800 m3 per hectare. On irrigated lands, plowing of potato fields is carried out necessarily with a soil cultivator, preventing the formation of a plow pan. Rows are located across the slope, or angle-wise. After watering space between rows are loosened (on heavy soils also before watering). During irrigation process it is necessary to apply higher quantities of organic and mineral fertilizers and to carry out a set of measures to control weeds, pests and diseases of potatoes.<br /><br /></p>

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