Eggshell thickness and reproduction in American kestrels exposed to chronic dietary lead

1984 ◽  
Vol 13 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Oliver H. Pattee
Keyword(s):  
Eggshell Thickness ◽  
American Kestrels

Environmentally Relevant Concentrations of DE-71 and HBCD Alter Eggshell Thickness and Reproductive Success of American Kestrels

2009 ◽  
Vol 43 (6) ◽  
pp. 2124-2130 ◽  
Author(s):  
Kim J. Fernie ◽  
J. Laird Shutt ◽  
Robert J. Letcher ◽  
Ian J. Ritchie ◽  
David M. Bird
Keyword(s):  
Reproductive Success ◽  
Eggshell Thickness ◽  
American Kestrels

Influence of forced renesting, seasonal date of laying, and female characteristics on clutch size and egg traits in captive American Kestrels

1982 ◽  
Vol 60 (1) ◽  
pp. 71-79 ◽  
Author(s):  
David M. Bird ◽  
Paul C. Laguë
Keyword(s):  
Clutch Size ◽  
Eggshell Thickness ◽  
Falco Sparverius ◽  
Egg Weight ◽  
American Kestrels ◽  
First Clutch ◽  
Egg Traits

Of 78 nesting attempts by captive American Kestrels (Falco sparverius) between 1974 and 1977, 95% successfully renested after removal of the first clutch. Replacement clutches had fewer eggs, longer eggs, and eggs with thicker shells than first clutches. Clutch size, egg length, eggshell thickness, and fresh egg weight declined seasonally. Renesting intervals were shorter in older, experienced layers and clutch size increased by 0.20 eggs with each additional year of age.

Reproductive changes in American kestrels (Falco sparverius) in relation to exposure to technical hexabromocyclododecane flame retardant

2011 ◽  
Vol 30 (11) ◽  
pp. 2570-2575 ◽  
Author(s):  
Kim J. Fernie ◽  
Sarah C. Marteinson ◽  
David M. Bird ◽  
Ian J. Ritchie ◽  
Robert J. Letcher
Keyword(s):  
Flame Retardant ◽  
Falco Sparverius ◽  
American Kestrels

scholarly journals Effect of selected feed additives on egg performance and eggshell quality in laying hens fed a diet with standard or decreased calcium content

2018 ◽  
Vol 18 (1) ◽  
pp. 167-183 ◽  
Author(s):  
Sylwester Świątkiewicz ◽  
Anna Arczewska-Włosek ◽  
Józefa Krawczyk ◽  
Witold Szczurek ◽  
Michał Puchała ◽  
...  
Keyword(s):  
Breaking Strength ◽  
Calcium Content ◽  
Egg Yolk ◽  
Feed Additives ◽  
Cholesterol Concentration ◽  
Eggshell Thickness ◽  
Performance Indices ◽  
Eggshell Quality ◽  
Laying Performance ◽  
Herb Extracts

Abstract The aim of the experiment with 240 ISA Brown hens fed the diets with standard or decreased Ca level was to evaluate the effect of selected feed additives on laying performance and eggshell quality. The hens were allocated to 10 treatments, each containing 12 cages (replicates) of 2 birds. A 2 × 5 experimental arrangement was used. From 26 to 70 wks of age, experimental diets containing 3.20 or 3.70% Ca were used. The diets were either not supplemented, or supplemented with sodium butyrate, probiotic bacteria, herb extracts blend or chitosan. The decreased dietary Ca reduced eggshell quality indices in older hens (43-69 wks) (P<0.05) without effect on performance indices. The addition of the probiotic, herb extracts, or chitosan increased the laying rate (P<0.05). In older hens, i.e. at 69 wk, chitosan increased eggshell thickness and breaking strength, while herb extracts increased eggshell thickness (P<0.05). There was no interaction between the experimental factors in performance and eggshell quality. The used feed additives had no influence on fatty acid profile of egg lipids, however diet supplementation with chitosan decreased cholesterol concentration in egg yolk lipids (P<0.05). It can be concluded that such feed additives as probiotic, herb extracts, or chitosan may positively affect performance and eggshell quality, irrespective of Ca dietary level.

The influence of Trichinella pseudospiralis infection on the behaviour of captive, nonbreeding American kestrels (Falco sparverius)

1988 ◽  
Vol 66 (7) ◽  
pp. 1685-1692 ◽  
Author(s):  
Michèle D. Saumier ◽  
Manfred E. Rau ◽  
David M. Bird
Keyword(s):  
Falco Sparverius ◽  
Competitive Fitness ◽  
American Kestrel ◽  
Behavioural Changes ◽  
Trichinella Pseudospiralis ◽  
Behavioural Effects ◽  
American Kestrels ◽  
Muscle Larvae ◽  
Adult Phase ◽  
Muscle Groups

Trichinella pseudospiralis infections induced mild behavioural changes in the American kestrel host (Falco sparverius) within the first 5 days postinoculation, a period that corresponds to the adult phase of the infection. However, more severe effects on mobility were precipitated as the larvae migrated and became established in the musculature. The debilitation persisted for at least 5 weeks postinoculation and involved a reduction in exercising, flying, elevated perching, and preening, and was accompanied by an increase in the frequency of walking and floor perching. Such behavioural effects, attributable to the presence of muscle larvae, may reduce the competitive fitness of infected individuals. The muscle larvae were randomly distributed among various muscle groups.

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 The Effect of Age and Genotype on Quality of Eggs in Brown Egg‑Laying Hybrids

2019 ◽  
Vol 67 (2) ◽  
pp. 407-414 ◽  
Author(s):  
Adam Kraus ◽  
Lukáš Zita
Keyword(s):  
Laying Hens ◽  
Egg Quality ◽  
Shape Index ◽  
Egg Laying ◽  
Average Weight ◽  
Eggshell Thickness ◽  
External Quality ◽  
Technological Value ◽  
Effect Of Age

The aim was to assess the internal and external quality of consumer eggs of egg‑laying hens of two selected genotypes depending on their age. All of these hens were kept in enriched cages. There were compared eggs from Hy‑Line Brown and ISA Brown hens at the age from 36 to 64 weeks. In total, 3840 eggs from 300 hens were evaluated. Quality of eggs was determined by their technological value. Statistically significant interactions (P = 0.001) between age and genotype were found in all evaluated parameters except for the yolk colour (P = 0.044), whereas there was not found interaction (P = 0.072) between age and genotype in eggshell strength. The significant effect of hens’ age was found in all evaluated parameters, with the only exception of the yolk colour. The results showed that the average weight of eggs, eggshell, albumen and yolk increased with the age. Also the eggshell proportion, its colour and yolk index values ​​increased, whereas the egg shape index, eggshell thickness and strength, albumen proportion, Haugh units, the albumen and the yolk index decreased. Statistically significant effect of the genotype was found in all evaluated parameters except for the yolk index. When comparing both genotypes, the eggs from ISA Brown hens had a better quality. The trend of deteriorating egg quality with age was confirmed.

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