The effect of food supply on the composition of Black-billed Magpie eggs

1988 ◽  
Vol 66 (3) ◽  
pp. 692-695 ◽  
Author(s):  
Wesley M. Hochachka
Keyword(s):  
Water Content ◽  
Food Supply ◽  
Egg Size ◽  
Supplemental Feeding ◽  
Pica Pica ◽  
Shell Mass ◽  
Supplemental Food ◽  
Effect Of Food ◽  
Egg Composition ◽  
And Control

Viability of hatching birds may be affected by the composition of the eggs from which they come. Egg composition may be influenced by the diet of the female. I examined whether wild Black-billed Magpies (Pica pica) varied the composition of their eggs in response to differences in food supply. Supplemental food was provided on some territories, and the composition of eggs from control and food-supplemented territories was compared. Supplemental feeding had few effects on egg composition. Egg size – water content relationships differed between eggs from food-supplemented and control territories and there was a greater variability in yolk and shell mass within clutches from food-supplemented territories. These results show that food supply to the female can affect the composition of an egg relative both to other eggs in the same clutch and to eggs in other clutches. However, it is not clear whether the observed variation in egg composition would have an effect on the viability of the eggs.

Variation in laying date, clutch size, egg size, and egg composition of yellow-headed blackbirds (Xanthocephalus xanthocephalus): a supplemental feeding experiment

1992 ◽  
Vol 70 (10) ◽  
pp. 1904-1911 ◽  
Author(s):  
Todd W. Arnold
Keyword(s):  
Food Availability ◽  
Egg Production ◽  
Egg Size ◽  
Energy Content ◽  
Laying Date ◽  
Food Supplementation ◽  
Supplemental Feeding ◽  
Xanthocephalus Xanthocephalus ◽  
Egg Composition ◽  
Nest Initiation

I studied the effects of food availability, habitat quality, and timing of breeding on egg production in yellow-headed blackbirds (Xanthocephalus xanthocephalus). Food availability was experimentally manipulated by providing females on six wetlands with supplemental food; six additional wetlands served as unsupplemented controls. Mean nest initiation dates varied by up to 6 d among wetlands, and supplementally fed blackbirds initiated nests 2 d earlier than controls, on average (although this latter difference was not quite significant; P = 0.07). Clutch size declined with laying date, but was unaffected by wetland location, food supplementation, or interactions between these two factors and laying date. Although egg size did not vary among wetlands or in relation to supplemental feeding, egg composition varied with both of these factors. All egg components except wet and dry shell and dry albumen varied among wetlands, whereas total water, wet yolk, and lean yolk were the only components that varied with food supplementation. Large blackbird eggs contained proportionately more water and albumen, but proportionately less yolk and shell. These patterns were somewhat compensatory, such that proportional protein and energy content did not vary with egg size; however, large eggs contained proportionately less fat than did small eggs. Proportional egg composition varied among wetlands (yolk and energy content), but was not affected by supplemental feeding. In general, egg production by yellow-headed blackbirds was not greatly affected by food availability. This may have been due to any of the following four factors: (1) inaccessibility of food supplements owing to competition between male and female blackbirds, (2) insufficient time for females to respond to food supplements, owing to rapid settlement and nest initiation, (3) a nutritionally inappropriate food supplement (i.e., protein availability may not have been enhanced among fed birds), or (4) superabundance of natural foods such that food availability was not limiting egg production.

Food shortage for breeding Black-billed Magpies (Pica pica): an experiment using supplemental food

1987 ◽  
Vol 65 (5) ◽  
pp. 1270-1274 ◽  
Author(s):  
Wesley M. Hochachka ◽  
David A. Boag
Keyword(s):  
Breeding Population ◽  
Egg Laying ◽  
Food Shortage ◽  
Laying Date ◽  
Food Supplementation ◽  
Natural Food ◽  
Supplemental Feeding ◽  
Pica Pica ◽  
Supplemental Food ◽  
Before And After

Supplemental food was provided to a breeding population of Black-billed Magpies (Pica pica), starting before and after eggs were laid, to determine if and when natural food was limited. The production of fledgling magpies was increased only when supplemental feeding was begun before laying. Laying date was also advanced when supplemental feeding began before laying, but clutch and egg size were not significantly changed. Because the two feeding treatments were conducted in different years, we cannot conclude whether natural food was limiting before or after egg laying. However, out data suggest that the former may have been the case. An improved design for food supplementation experiments, which can be used to determine the time of food shortage, is suggested.

scholarly journals Reduction of Provisioning Effort in Response to Experimental Manipulation of Chick Nutritional Status in the Horned Puffin

The Condor ◽  
2002 ◽  
Vol 104 (4) ◽  
pp. 842-847 ◽  
Author(s):  
Ann M. A. Harding ◽  
Thomas I. van Pelt ◽  
John F. Piatt ◽  
Alexander S. Kitaysky
Keyword(s):  
Experimental Manipulation ◽  
Nutritional Requirements ◽  
Supplemental Feeding ◽  
Food Provisioning ◽  
Feeding Experiment ◽  
Control Groups ◽  
Supplemental Food ◽  
Parental Provisioning ◽  
And Control ◽  
Horned Puffin

AbstractUsing a supplemental feeding experiment, we investigated the ability of adult Horned Puffins to decrease provisioning effort in response to reduced nutritional requirements of chicks. We found no difference between experimental and control groups in parental provisioning before supplementary feeding was initiated. After receiving supplemental food for seven days, experimental chicks grew faster, gained more mass and received 87% less food from their parents than did control chicks. These results demonstrate that Horned Puffin parents can decrease food provisioning in response to a decrease in their chick nutritional requirements.Reducción del Esfuerzo de Aprovisionamiento en Respuesta a la Manipulación Experimental del Estatus Nutricional de Pichones en Fratercula corniculataResumen. Usando un experimento de suplementación alimenticia, investigamos la habilidad de adultos de Fratercula corniculata de disminuir el esfuerzo de aprovisionamiento en respuesta a una reducción en la demanda nutricional de los pichones. No encontramos diferencias entre grupos experimentales y control en el aprovisionamiento parental antes que la suplementación de alimento fuera iniciada. Luego de que los pichones recibieron comida adicional durante siete días, los pichones experimentales crecieron más rápido, ganaron más peso y recibieron 87% menos alimento de sus padres que los pichones control. Estos resultados demuestran que los padres de F. corniculata pueden disminuir el aprovisionamiento en respuesta a una reducción en los requerimientos nutricionales de sus pichones.

Variation in Weight, Size, and Sex Ratio of Coccinellid Adults (Coleoptera: Coccinellidae)

1966 ◽  
Vol 98 (6) ◽  
pp. 639-644 ◽  
Author(s):  
B. C. Smith
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Water Content ◽  
Food Supply ◽  
Sexual Differences ◽  
Intraspecies Variation ◽  
Food Scarcity ◽  
Food Requirement ◽  
Males And Females

AbstractThe weight and size of coccinellid adults varied with species, sex, and feeding. Intraspecies variation in weight was generally similar in the eight species studied. Females were more variable than males in body size. Females of some species were heavier and larger than males, and species can be classified on a basis of difference in the weight and size of the sexes.An increase in the food supply after a period of food scarcity affected the sex ratio, as the minimum food requirement of females was greater than males. Females increased in weight more rapidly than males after feeding. The availability of food in the field affected the weight and size of some species. Adult water content was influenced by feeding but not by sex or the quantity of food given to the larva.Males were more abundant in species with small sexual differences in weight and size. The degree of difference in weight and size between males and females may be used as a criterion to select species that are best adapted to survive when food is scarce.

scholarly journals The effect of food additive on physicochemical characteristics of seaweed stick snack and consumer acceptance

2021 ◽  
pp. 102-113
Author(s):  
Sumartini ◽  
Sellen Gurusmatika ◽  
Wan Amira
Keyword(s):  
Food Additives ◽  
Sensory Perception ◽  
Physicochemical Characteristics ◽  
Proximate Analysis ◽  
Traditional Use ◽  
International Demand ◽  
Effect Of Food ◽  
Induce Change ◽  
And Control ◽  
Derivative Products

Seaweed is considered high class marine and fisheries sector in international demand for its derivative products. One of traditional use of seaweed as food is stick snack which is widely consumed due to its crunchiness and deliciousness. The objective of this study was to characterize the proximate analysis, hardness, and sensory perception of stick snack derived from seaweed. Seaweed stick were prepared with varying food additives such as  sodium acid phyorposphate (SAPP), steaoryl lactylate (SSL), sodium bicarbonate (NaHCO3), and control (without addition of food additives). The results confirmed that the use of food additives induce change in proximate, hardness, and sensory perception. Seaweed stick with addition NaHCO3 has the highest fat content while seaweed stick with addition of SAPP has  the highest crispness. In addition, sensory test showed that seaweed stick with addition with NaHCO3 provide the highest acceptance in texture and flavour.

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