Ecological Studies of the Black Swan I. The Egg, Clutch and Incubation

1977 ◽  
Vol 4 (1) ◽  
pp. 59 ◽  
Author(s):  
LW Braithwaite
Keyword(s):  
Incubation Period ◽  
Clutch Size ◽  
Egg Size ◽  
Adaptive Significance ◽  
Moisture Loss ◽  
Black Swan ◽  
Black Swans ◽  
The Difference ◽  
Method Of Assessment ◽  
Autumn And Winter

Statistics are given for egg dimensions, clutch size, laying rate and incubation period in black swans nesting at Lake George and Lake Bathurst, N.S.W., and compared with data from other studies. Methods of determining clutch size and incubation dates are given and examined. Emphasis is placed on the importance of the method of assessment of clutch size in comparisons within and between studies. There was evidence of two size classes of eggs, possibly related to factors of age or breeding experience, the smaller class being laid in summer breeding, during an exceptional abundance of food, but not in winter when food may have been limiting. Egg size varied significantly, according to sequence in the clutch. The adaptive significance of egg size is discussed; moisture loss may be important in the evolution of egg size. Clutch size varied significantly according to the location and date of nesting. The reasons for the variation were, possibly, both in the nutritional value of the food available and in its relative temporal and physical availability and the swans' abllity to metabolize it. Possible evolutionary determinants of average clutch size in the black swan are considered. Moisture losses from the egg may again he important. The laying rate was simdar to that reported elsewhere. The mean incubation period was 40.45 days and most clutches ranged from 39 to 43 days. Clutches laid in autumn and winter took marginally longer to hatch than clutches laid in spring and summer, possibly due to effects of ambient temperature; the difference was probably not of particular adaptive significance.

scholarly journals GEOGRAPHIC VARIATION IN CLUTCH SIZE AMONG Lophura AND Syrmaticus PHEASANTS ON TAIWAN AND MAINLAND OF CHINA

2006 ◽  
Vol 28 (63) ◽  
Author(s):  
Zuhao Huang ◽  
Naifa Liu
Keyword(s):  
Life History ◽  
Environmental Factors ◽  
Clutch Size ◽  
Reproductive Strategies ◽  
Egg Size ◽  
Significant Positive Correlation ◽  
Weather Condition ◽  
Life History Evolution ◽  
Breeding Strategy ◽  
The Difference

Clutch size, the important parameters of bird reproduction, directly influences bird reproductive result. The difference of interspecific or/and intraspecific clutch size has been widely applied to explain life history evolution. In order to know the factors limiting clutch size of pheasants on island and examine Ashmole’s hypothesis and Cody’s hypothesis,clutch size and egg size of Lophura swinhoii and Syrmaticus mikado on Taiwan were compared with those of relative species on mainland of China. The average clutch size of L.swinhoii and S.mikado on Taiwan were significantly less than those of relative species on mainland. But the egg size of the two pheasants on Taiwan was notably bigger than those of relative species on mainland. They reduced clutch size and increased egg sizes, their reproductive strategies tended to k-selection. While the relative species on mainland laid more and smaller eggs, their reproductive strategies tended to rselection. The analysis on environmental factors showed the pheasants on Taiwan didn’t support Ashmole’s and Cody’s hypotheses. Unexpected weather condition on island might lead to the breeding strategy on island tend to k-selection. Among Gallinaceous birds, there was a highly significant positive correlation between clutch size and their distributed area, and the number of subspecies. The breeding strategy of pheasants on island was determined by the effects of area and heredity.

The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger

2020 ◽  
Vol 63 (9) ◽  
pp. 2921-2929
Author(s):  
Alan H. Shikani ◽  
Elamin M. Elamin ◽  
Andrew C. Miller
Keyword(s):  
Ex Vivo ◽  
Moisture Loss ◽  
Speaking Valve ◽  
Time Zero ◽  
In Series ◽  
Turbulent Airflow ◽  
The Difference ◽  
Loss Efficiency ◽  
Heat And Moisture ◽  
Lung Simulation

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance ( R airflow ) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow ( Q ) amplitude and R airflow , as indicated by a pressure drop ( P Drop ) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T 0 ) and after 24 hr of moisture testing (T 24 ) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T 0 and T 24 ). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.

Parental Investment in Clutch Size and Egg Size in the Ural Owl Strix uralensis

1986 ◽  
Vol 17 (4) ◽  
pp. 309 ◽  
Author(s):  
Hannu Pietiainen ◽  
Pertti Saurola ◽  
Risto A. Vaisanen
Keyword(s):  
Clutch Size ◽  
Parental Investment ◽  
Egg Size ◽  
Ural Owl

Novel Method of Assessing Practical Intelligence Acquired in Mechatronics Laboratory Classes

2015 ◽  
pp. 895-928
Author(s):  
Zol Bahri Razali
Keyword(s):  
Engineering Education ◽  
Engineering Students ◽  
Explicit Knowledge ◽  
Assessment Instruments ◽  
Practical Intelligence ◽  
Work Related ◽  
Novel Method ◽  
The Difference ◽  
Representative Work ◽  
Method Of Assessment

Practical intelligence is often referred to as the ability of a person to solve practical challenges in a given domain. The lack of practical intelligence may be due to the way in which explicit knowledge is valued and subsequently assessed in engineering education, namely via examinations, tests, laboratory reports, and tutorial exercises. The lack of effective assessments on practical intelligence indicates implicit devaluation, which can significantly impair engineering students' ability to acquire practical intelligence. To solve this problem, the authors propose a new method of assessment for measuring practical intelligence acquired by engineering students after performing engineering laboratory classes. The novices-experts approach is used in designing the assessment instruments, based on the behaviors' of novices/experts observed and novices/experts representative work-related situations. The practical intelligence can be measured by calculating the difference between participants' and the experts' ratings; the closer the novices to experts, the higher the practical intelligence acquired.

scholarly journals Egg Size, Eggshell Porosity, and Incubation Period in the Marine Bird Family Alcidae

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 307-315
Author(s):  
Karen Zimmermann ◽  
J. Mark Hipfner
Keyword(s):  
Incubation Period ◽  
Egg Size ◽  
Interspecific Variation ◽  
Egg Mass ◽  
Proximate Mechanisms ◽  
Diffusion Limited ◽  
Evolutionary Changes ◽  
Incubation Periods ◽  
Avian Incubation ◽  
Embryonic Metabolism

Abstract Although the ultimate factors that influence the duration of avian incubation periods are well known, we know much less about the proximate mechanisms by which birds adjust incubation period in response to selection. We tested the hypothesis that an adjustment in eggshell porosity is one such proximate mechanism (i.e., that avian species with higher ratios of incubation period to egg size lay eggs with less porous shells). Eggshell porosity affects the rate of gaseous exchange between the developing embryo and the external environment; thus, to the extent that embryonic metabolism is diffusion-limited, eggshell porosity could directly determine incubation period. To test that hypothesis, we collected eggs from seven species of Alcidae, a family of marine birds that exhibits an unusual degree of interspecific variation in incubation period, and measured egg mass and eggshell porosity (determined by the number and size of pores and the thickness of the shell). Incubation periods were obtained from the literature. Egg mass and eggshell porosity combined explained 87% of the variation in incubation period among the seven species, which included at least one member of each of the six main alcid lineages. As predicted, eggshell porosity and incubation period were negatively related, after controlling for egg mass. Our results are consistent with the hypothesis that evolutionary changes in avian incubation period may be attributed, at least in part, to adjustments in eggshell porosity. Taille de l’Œuf, Porosité de la Coquille et Période d’Incubation chez les Oiseaux Marins de la Famille des Alcidés

scholarly journals Male harassment leads to fitness costs for females by disrupting oviposition site preferences

2020 ◽  
Vol 31 (3) ◽  
pp. 611-617
Author(s):  
Elisabeth Bacon ◽  
Flavia Barbosa
Keyword(s):  
Clutch Size ◽  
Sexual Conflict ◽  
Egg Size ◽  
Callosobruchus Maculatus ◽  
Optimal Number ◽  
Oviposition Site ◽  
Fitness Costs ◽  
Male Harassment ◽  
Oviposition Substrate ◽  
Pinto Beans

Abstract In many species, a difference in the optimal number of copulations for males and females leads to sexual conflict. This is well documented in the bean beetle Callosobruchus maculatus, where both sexes mate multiply and females incur fitness costs from injuries caused by the male genitalia. Here, we demonstrate that sexual conflict also decreases female fitness due to male harassment. We hypothesized that harassment costs would come as 1) decreased clutch size, egg size, or both and by 2) disruption of female preference for higher-quality oviposition substrate. Mated females were housed with two bean types—cowpeas, their preferred natal hosts, and toxic pinto beans. They were then submitted to either no, moderate, or high male harassment in the oviposition site. Females under harassment produced smaller clutch sizes but not smaller eggs, resulting in the absence of an egg-size/clutch-size trade-off. Additionally, females did not exhibit a preference for their natal cowpeas hosts over toxic pinto beans when males were present at the oviposition site, although they do so when harassing males are not present. Harassment disrupted female responses to variation in oviposition substrate quality, resulting in considerable fitness consequences in the form of lower offspring production and survival.

scholarly journals Ultraviolet Degradation in Carotenoid Patches: Live Versus Museum Specimens of Wood Warblers (Parulidae)

The Auk ◽  
2005 ◽  
Vol 122 (3) ◽  
pp. 793-802 ◽  
Author(s):  
Gabriel D. McNett ◽  
Karen Marchetti
Keyword(s):  
Natural Populations ◽  
Adaptive Significance ◽  
Color Variation ◽  
Museum Specimens ◽  
The Past ◽  
Wood Warblers ◽  
Color Spectrum ◽  
The Difference ◽  
Using Data ◽  
Source Materials

Abstract Accurate assessment of color is essential in testing the adaptive significance of color variation in avian plumage. Over the past decade, use of objective methods for assessing color has increased, with particular emphasis on ultraviolet (UV) wavelengths. Researchers have used various source materials, most notably museum specimens, to extend or represent color measurements of individuals in natural populations. Here, we address whether the colors seen in museum specimens accurately represent the colors seen in natural populations. We focus on UV wavelengths and carotenoid-derived colors across 10 species of wood-warblers (Parulidae). Our results indicate an uneven decrease in brightness across the color spectrum, with greater relative decrease in shorter wavelengths in museum specimens. That decrease leads to differences in both hue and chroma between living and museum specimens. The difference from live specimens appears to increase with the museum specimen's age. Our results suggest that caution is needed when using data from museum specimens to test hypotheses on plumage coloration, particularly those involving communication. Degradación Ultravioleta en Parches de Carotenoides: Especímenes Vivos versus Especímenes de Museo de Especies de la Familia Parulidae

Developing a census method based on sight counts to estimate rabbit (Oryctolagus cuniculus) numbers

2003 ◽  
Vol 30 (5) ◽  
pp. 487 ◽  
Author(s):  
Dylan W. Poole ◽  
Dave P. Cowan ◽  
Graham C. Smith
Keyword(s):  
Population Size ◽  
Field Trials ◽  
Population Estimates ◽  
Economic Costs ◽  
Natural Conditions ◽  
Commercial Farms ◽  
The Mean ◽  
The Difference ◽  
Study Sites ◽  
Autumn And Winter

A rabbit-census method, based on systematic counts conducted at night or at dawn and dusk, was developed and validated in terms of estimating the total number of rabbits present in a given area. Initially, models were developed under semi-natural conditions to describe the relationships between the numbers of rabbits counted and population size. Confidence limits were also calculated. The models were developed by comparing rabbit counts with the actual number of rabbits present, from a known population of animals. Only spotlight counts at night were considered reliable enough to estimate rabbit population size. During the autumn and winter months these represented ~60% of the population present. The model was subsequently validated, in two different exercises, following a series of field trials conducted under a variety of conditions on commercial farms. Initially, population estimates derived from the model were compared with those calculated using an alternative census technique. Population estimates, using the two techniques, were very similar at nine of the ten study sites. A second validation exercise was also conducted whereby the number of rabbits removed at each of the sites was compared with the difference between the mean pre- and post-removal spotlight counts. The results further supported the proposition that spotlight counts represent ~60% of the population present, with the difference between the two mean spotlight counts representing 61.2% (± 11.0, s.d.) of the number of rabbits removed. The census method therefore shows considerable promise as a means to estimate rabbit numbers under a range of agricultural conditions and therefore has the potential to predict accurately the economic costs of rabbit damage and also to gauge the effectiveness of various methods of rabbit control.

Black swans and canards in two predator – one prey model

2019 ◽  
Vol 14 (4) ◽  
pp. 408 ◽  
Author(s):  
Elena Shchepakina
Keyword(s):  
Invariant Manifold ◽  
Black Swan ◽  
Black Swans ◽  
Prey Model ◽  
Slow Invariant Manifold

In this paper, we show how canards can be easily caught in a class of 3D systems with an exact black swan (a slow invariant manifold of variable stability). We demonstrate this approach to a canard chase via the two predator – one prey model. It is shown that the technique described allows us to get various 3D oscillations by changing the shape of the trajectories of two 2D-projections of the original 3D system.

Sign in / Sign up

Export Citation Format

Share Document