Effect of Nest Characteristics on Thermal Properties, Clutch Size, and Reproductive Performance for an Open-Cup Nesting Songbird

2017 ◽  
Vol 10 (2) ◽  
pp. 107-118 ◽  
Author(s):  
Michael E. Akresh ◽  
Daniel R. Ardia ◽  
David I. King
Keyword(s):  
Thermal Properties ◽  
Heat Loss ◽  
Clutch Size ◽  
Structural Characteristics ◽  
Nest Structure ◽  
Cavity Nesting ◽  
Nestling Condition ◽  
Hot Days ◽  
Fitness Benefits ◽  
Prairie Warbler

Maintaining avian eggs and young at optimum temperatures for development can increase hatching success and nestling condition, but this maintenance requires parental energetic demands. Bird nests, which often provide a structure to safely hold the eggs and nestlings and protect them from predators, can additionally be designed to help maintain eggs’ optimum temperatures by minimising heat loss, especially in climates where eggs cool rapidly when unattended. We collected and measured Prairie Warbler ( Setophaga discolor) nests in western Massachusetts, U.S. in 2009 and conducted a climate-controlled, nest-cooling experiment to determine how nest characteristics affect thermal properties for small, open-cup nesting birds. We then assessed if nests with better insulation properties resulted in any fitness benefits, and also tested if nest structural characteristics affected birds’ fitness. We found that nest characteristics influenced their thermal properties, with thicker, heavier, and larger nests having slower cooling rates and higher predicted equilibrium egg temperatures. Both nest cup depth and clutch size significantly declined over the breeding season, and we observed a trend, although non-significant, that nests with shallower cups had smaller clutches. Contrary to studies on cavity-nesting birds, we found no significant effects of nest thermal properties or nest structure on hatching and fledging success, nestling condition, brood parasitism, or nest survival. Prairie Warblers in our study site may already be adapted to build nests within a range that maximises their fitness. Furthermore, studies have shown that open-cup nests of other species are relatively thicker and more insulated in colder environments at higher latitudes than our study. Instead of building nests to solely minimise heat loss, open-cup nesting birds in temperate climates may also be driven by opposing selection pressures when building their nests, such as to prevent nestlings from overheating during hot days.

scholarly journals Opto-thermal properties of fibers — 2. Structural characteristics of cold drawn annealed Egyptian polyester (PET) fibers

1997 ◽  
Vol 16 (4) ◽  
pp. 303-325 ◽  
Author(s):  
A.A. Hamza ◽  
I.M. Fouda ◽  
M.A. Kabeel ◽  
E.A. Seisa ◽  
F.M. El-sharkawy
Keyword(s):  
Thermal Properties ◽  
Structural Characteristics ◽  
Pet Fibers

scholarly journals How Many Baskets? Clutch Sizes That Maximize Annual Fecundity of Multiple-Brooded Birds

The Auk ◽  
2001 ◽  
Vol 118 (4) ◽  
pp. 973-982 ◽  
Author(s):  
George L. Farnsworth ◽  
Theodore R. Simons ◽  
J. Brawn
Keyword(s):  
Clutch Size ◽  
Breeding Season ◽  
Nest Predation ◽  
Reproductive Effort ◽  
Nest Survival ◽  
Survival Rates ◽  
Season Length ◽  
Deterministic Models ◽  
Cavity Nesting ◽  
Theoretical Issues

Abstract We developed deterministic models on the basis of nest survival rates and renesting behavior capable of predicting annual fecundity in birds. The models calculate probabilities of fledging from one to four nests within a discrete breeding season. We used those models to address theoretical issues related to clutch size. In general, birds require at least one day to lay an egg, and many species delay incubation until their entire clutch is laid. Because it takes longer to complete a larger clutch, and fewer such clutches can fit into a limited breeding season, there exists a clutch size for which annual fecundity is maximized. We asked, for a given amount of reproductive effort (i.e. a set number of eggs), does the age-old maxim “don't put all your eggs in one basket” apply? If so, in how many “baskets” should a nesting bird place its eggs? The answer depends on both likelihood of nest predation and length of the breeding season. Those results are consistent with the observed increase in clutch size with latitude (shorter breeding season length) and larger clutch sizes characteristic of cavity-nesting species (with higher nest survival rates). The models also predict that the size of replacement clutches should decrease as the breeding season progresses, and that intraseasonal decline in clutch size should be more pronounced when the breeding season is short.

scholarly journals Interpopulation variation in nest architecture in a secondary cavity-nesting bird suggests site-specific strategies to cope with heat loss and humidity

The Auk ◽  
2017 ◽  
Vol 134 (2) ◽  
pp. 281-294 ◽  
Author(s):  
Esteban Botero-Delgadillo ◽  
Nicole Orellana ◽  
Daniela Serrano ◽  
Yanina Poblete ◽  
Rodrigo A. Vásquez
Keyword(s):  
Heat Loss ◽  
Nest Architecture ◽  
Site Specific ◽  
Cavity Nesting ◽  
Interpopulation Variation

Calorific and Thermal Properties of Natural Rubber in the Oriented and Non-Oriented States

1956 ◽  
Vol 29 (3) ◽  
pp. 789-793
Author(s):  
B. I. Gengrinovich
Keyword(s):  
Thermal Properties ◽  
Natural Rubber ◽  
Physical State ◽  
Structural Characteristics ◽  
Amorphous State ◽  
Qualitative Change ◽  
Original Length ◽  
Degree Of Orientation ◽  
High Polymers

Abstract The structural characteristics of high polymers and the sharp dependence of their properties on the physical state create a need for a detailed study of these materials in the region where their physical state undergoes a qualitative change. Besides, a study of the phase transitions of high polymers which crystallize is of independent interest. The study of the transition of natural rubber from the oriented crystalline state to the non-oriented amorphous state was the problem of this work. The determination of calorific and thermal properties in the transition region was adopted as the method of investigation. It should be noted that, for rubbers, these properties have been studied to a much lesser extent than have the other thermodynamic properties, particularly the mechanical properties. In order to obtain crystalline rubber, strips of smoked sheet were subjected to repeated rapid stretching at 50°, followed by cooling of the stretched samples to 12–14° C. The stress applied to the rubber during stretching overcomes the deorienting effect of the thermal motion, which impedes the crystallization of non-deformed rubber. At the same time, the heating employed promotes a more complete straightening of the chains since, during heating, intermolecular action diminishes and the chaotically-grouped oriented portions of the macromolecules present in the samples are disrupted. Rapid cooling of the oriented rubber, obtained under such conditions, to temperatures below the melting point of the crystals which formed led to the preservation of the physical state, which was distinguished by an increase of the crystalline phase content, and by a higher degree of orientation, compared with the state of rubber crystallized during the same time by lowering the temperature without stretching. On an average, the extent of stretching amounted to 1400 per cent of the original length.

scholarly journals The Influence of Lignin Diversity on the Structural and Thermal Properties of Polymeric Microspheres Derived from Lignin, Styrene, and/or Divinylbenzene

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2847 ◽  
Author(s):  
Marta Goliszek ◽  
Beata Podkościelna ◽  
Olena Sevastyanova ◽  
Barbara Gawdzik ◽  
Artur Chabros
Keyword(s):  
Thermal Properties ◽  
Structural Characteristics ◽  
Polymer Network ◽  
Eucalyptus Grandis ◽  
Nitrogen Adsorption ◽  
Optical Microscope ◽  
Scanning Calorimetry ◽  
Promising Alternative ◽  
Synthetic Materials ◽  
The Impact

This work investigates the impact of lignin origin and structural characteristics, such as molecular weight and functionality, on the properties of corresponding porous biopolymeric microspheres obtained through suspension-emulsion polymerization of lignin with styrene (St) and/or divinylbenzene (DVB). Two types of kraft lignin, which are softwood (Picea abies L.) and hardwood (Eucalyptus grandis), fractionated by common industrial solvents, and related methacrylates, were used in the synthesis. The presence of the appropriate functional groups in the lignins and in the corresponding microspheres were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), while the thermal properties were studied by differential scanning calorimetry (DSC). The texture of the microspheres was characterized using low-temperature nitrogen adsorption. The swelling studies were performed in typical organic solvents and distilled water. The shapes of the microspheres were confirmed with an optical microscope. The introduction of lignin into a St and/or DVB polymeric system made it possible to obtain highly porous functionalized microspheres that increase their sorption potential. Lignin methacrylates created a polymer network with St and DVB, whereas the unmodified lignin acted mainly as an eco-friendly filler in the pores of St-DVB or DVB microspheres. The incorporation of biopolymer into the microspheres could be a promising alternative to a modification of synthetic materials and a better utilization of lignin.

scholarly journals Maternal Condition and Nestling Sex Ratio in House Wrens

The Auk ◽  
2002 ◽  
Vol 119 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Linda A. Whittingham ◽  
Stacy M. Valkenaar ◽  
Nicole E. Poirier ◽  
Peter O. Dunn
Keyword(s):  
Sex Ratio ◽  
Good Condition ◽  
Poor Quality ◽  
Maternal Condition ◽  
House Wren ◽  
House Wrens ◽  
Extrapair Mating ◽  
Female Condition ◽  
Nestling Condition ◽  
Fitness Benefits

Abstract Parents are expected to vary the sex ratio of their offspring in relation to the sex-specific fitness benefits. However, benefits of producing sex-biased broods may be dependent on condition of the female. For example, mothers in good condition could achieve greater fitness if they produced high-quality sons, whereas, mothers in poor condition would gain more by producing daughters rather than poor-quality sons. As a consequence, we would expect to see a relationship between female condition and sex ratio of offspring. We examined effect of maternal condition on nestling condition and sex ratio in the House Wren (Troglodytes aedon). Overall sex ratio of nestlings in the population was not biased, but females in better condition produced relatively more sons. Overall positive relationship between female condition and proportion of male offspring was due to second broods, which were significantly male-biased and more likely to be produced by females in good condition. Females in better condition also tended to provision young more often and produced both male and female nestlings in better condition. Polygyny and extrapair mating are common in House Wrens. If males in good condition are more likely to be successful breeders as adults, then it may benefit mothers in good condition to produce more sons.

The shape of eggs in different-sized clutches of the house wren (Troglodytes aedon)

2001 ◽  
Vol 79 (8) ◽  
pp. 1527-1531 ◽  
Author(s):  
L Scott Johnson ◽  
Jennifer E Leyhe ◽  
Caryn Werner
Keyword(s):  
Clutch Size ◽  
Large Set ◽  
Troglodytes Aedon ◽  
House Wren ◽  
House Wrens ◽  
Female Body Size ◽  
Tree Cavities ◽  
Cavity Nesting ◽  
Egg Shape ◽  
Specific Variation

The substantial inter- and intra-specific variation that occurs in the shape of birds' eggs remains largely unexplained. Several researchers have hypothesized that selection will favour a shape that results in the most compact fit of eggs under the incubating parent. Mathematical modeling has suggested that optimal egg shape depends on the number of eggs laid. We tested predictions of one previously published model by comparing the shape of eggs in clutches of 4, 5, 6, 7, and 8 eggs in a Wyoming, U.S.A., population of the house wren (Troglodytes aedon), a small, cavity-nesting songbird whose eggs vary considerably in shape. Contrary to predictions of the model, the typical shapes of eggs from different-sized clutches were very similar. Moreover, slight differences in shape detected were not in directions predicted by the model. There may be less selection on house wrens to adjust egg shape to clutch size because they lay eggs that are small relative to female body size, because eggs are placed in a deep spherical cup that conforms to the shape of the female's abdomen and because nests are to some degree insulated, being located in tree cavities. Full evaluation of the model will require comparisons of egg shape and clutch size in a large set of species that differ in natural-history characteristics such as egg size, nest shape, and nest placement.

Polybutadiene rubber/exfoliated graphite nanocomposites: Impact of filler on the thermal, mechanical and permeability characteristics

2019 ◽  
Vol 35 (3) ◽  
pp. 138-148
Author(s):  
Soney C George ◽  
Jiji Abraham ◽  
Thomasukutty Jose ◽  
Riya Thomas ◽  
Teresa Jacob ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Structural Characteristics ◽  
Nitrogen Atmosphere ◽  
Exfoliated Graphite ◽  
Melt Mixing ◽  
Permeability Characteristics ◽  
Polybutadiene Rubber ◽  
Permeation Studies

In this report, we demonstrate that both mechanical behaviour and thermal stability of polybutadiene rubber (PBR) nanocomposites could be improved by incorporating exfoliated graphite (EG) using melt mixing method. Incorporation of the filler EG in the polybutadiene (PBD) matrix is confirmed by infrared spectra and X-ray diffraction analysis. The structural characteristics, mechanical properties and thermal properties of these newly modified PBR nanocomposites were systematically analysed and studied. Thermal properties of the nanocomposites were studied using thermogravimetric analysis under nitrogen atmosphere. Thermogravimetric studies showed that PBR8 is having higher thermal stability than that of the PBR gum sample. Mechanical properties like tensile strength, Young’s modulus, tear strength, hardness and compression set of the nanocomposites were studied. Mechanical properties are also high for the modified PBR nanocomposites with maximum filler content. The permeability of organic vapours such as dichloromethane (CH2Cl2), chloroform (CHCl3) and carbon tetrachloride (CCl4) through PBR/EG nanocomposites was also studied. In vapour permeation studies, PBR4 exhibits the least permeability in CH2Cl2, CHCl3 and CCl4 solvents. Polybutadiene rubber–natural graphite (PBR/NG) nanocomposites were also prepared for comparison.

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