scholarly journals Does Differential Access to Protein Influence Differences in Timing of Breeding of Florida Scrub-Jays (Aphelocoma Coerulescens) in Suburban and Wildland Habitats?

The Auk ◽  
2003 ◽  
Vol 120 (4) ◽  
pp. 1114-1127 ◽  
Author(s):  
Stephan J. Schoech ◽  
Reed Bowman
Keyword(s):  
Luteinizing Hormone ◽  
Body Condition ◽  
Condition Index ◽  
Egg Laying ◽  
Timing Of Breeding ◽  
Florida Scrub ◽  
Calendar Date ◽  
Aphelocoma Coerulescens ◽  
Endogenous Protein ◽  
Total Body

Abstract Timing of breeding in Florida Scrub-Jays (Aphelocoma coerulescens) varies both within and between years. Social status and breeding experience may explain much of the within-year variation, but the availability of certain foods may partially explain between-year patterns. Scrub-jays in suburban habitats with access to unlimited human-provided foods breed earlier and with less between-year variation in timing of breeding than jays in wildland habitats. We hypothesized that those differences in timing of breeding result from access to human-provided foods in the suburban site. Human-provided food may influence timing of breeding by improving the overall body condition of females, or it may influence breeding by providing nutrients essential for breeding. If condition mediated, breeding females in the two habitats should differ in certain physiological parameters relative to time before egg laying and calendar date. If the effect is not related to body condition, we expect differences in prebreeding females relative to calendar date, but not in relation to time before egg laying. To test those predictions, we measured plasma levels of total protein, calcium, luteinizing hormone, and estradiol. We also measured variables associated with body condition—body mass, a size-corrected condition index, and total body lipids. Most variables tended to increase with both days before laying and calendar date, except total body lipids, which decreased. Suburban females had higher levels of plasma protein relative to both days before egg laying and calendar date than female breeders in the wildland habitat. Luteinizing hormone differed between sites relative to calendar date but not days before laying. Our data suggest that suburban scrub-jays with access to predictable sources of high-quality human-provided foods accumulate endogenous protein that can be used to breed earlier.

Are roads and traffic sources of physiological stress for the Florida scrub-jay?

2012 ◽  
Vol 39 (4) ◽  
pp. 301 ◽  
Author(s):  
Gina M. Morgan ◽  
Travis E. Wilcoxen ◽  
Michelle A. Rensel ◽  
Stephan J. Schoech
Keyword(s):  
Body Mass ◽  
Body Condition ◽  
Physiological Stress ◽  
Condition Index ◽  
Physiological Effects ◽  
Negative Effects ◽  
Florida Scrub ◽  
The Road ◽  
Threatened And Endangered Species ◽  
Chronic Stressor

Context Anthropogenic disturbances induce physiological and behavioural responses in numerous species. The negative effects of human disturbance are of special concern to threatened and endangered species. Aims The present study aims to compare physiological stress measures and reproductive success of Florida scrub-jays (Aphelocoma coerulescens) living near roads with jays that live away from roads. Specifically, it aims to test whether roads are stressful. Methods We assessed physiological measures that can serve as indicators of ‘stress’ to determine whether a highway that bisects our study site had physiological effects on adult male Florida scrub-jays. We captured male breeders from three territory types, including scrub habitat that (1) bordered a highway with a grassy shoulder that created an ‘edge’ habitat (roadside), (2) bordered human-maintained habitat (a plowed firebreak of sand with adjacent pasture) that served as a control for the edge-effect of the road (pasture) and (3) contained only natural scrub habitat (interior). We measured baseline concentrations of the stress hormone corticosterone (CORT), body mass, and a suite of longitudinal body measures to generate a body condition index in males from each territory type over three breeding seasons. Key results Roadside jays had greater body mass than did interior and pasture jays, although there were no differences in overall baseline CORT concentrations or body condition among territory classes. There was no difference in clutch initiation date or size and nestling and independent-young survival. Conclusions Our results suggest that the road through our study site has physiological effects on Florida scrub-jays; however, there is mixed evidence as to whether it acts as a chronic stressor. Implications Our findings provide evidence that roads and road-associated disturbance has neutral or potentially beneficial physiological effects of roads on Florida scrub-jays. Knowledge of these effects of roads and disturbance on jays will hopefully provide additional opportunities to improve conservation of this species.

Corticosterone administration does not affect timing of breeding in Florida scrub-jays (Aphelocoma coerulescens)

2007 ◽  
Vol 52 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Stephan J. Schoech ◽  
Reed Bowman ◽  
Eli S. Bridge ◽  
Gina M. Morgan ◽  
Michelle A. Rensel ◽  
...  
Keyword(s):  
Timing Of Breeding ◽  
Florida Scrub ◽  
Aphelocoma Coerulescens

scholarly journals Body Size and Condition, Timing of Breeding, and Aspects of Egg Production in Eastern Kingbirds

The Auk ◽  
1986 ◽  
Vol 103 (3) ◽  
pp. 465-476 ◽  
Author(s):  
Michael T. Murphy
Keyword(s):  
Body Size ◽  
Body Condition ◽  
Egg Production ◽  
Egg Quality ◽  
Flight Muscle ◽  
Egg Laying ◽  
Female Size ◽  
Timing Of Breeding ◽  
Muscle Weight ◽  
Egg Weight

Abstract Variation in timing of breeding in Eastern Kingbirds (Tyrannus tyrannus) was correlated only weakly with external morphological characters, but was correlated positively and significantly with estimates of body size based on measurements of skeletons and muscle weights. Small females apparently held a reproductive advantage in being able to mobilize resources for reproduction before large females. Egg weight was independent of all measures of female size, but was directly and significantly (P = 0.03) correlated with standard flight muscle weight, a relative index of body condition. Egg size was thus a function more of female body condition than size. On average, shell, yolk, and albumen comprised 5.6%, 21.9%, and 72.5%, respectively, of fresh egg weight. Dry albumen and dry shell increased proportionately with fresh egg weight, but dry yolk did not. Total protein, lipid, and energy of fresh eggs all increased proportionately with weight. Comparison of egg composition and standard flight muscle weight of laying females indicated moderate positive, although nonsignificant, correlations between body condition and measures of egg quality, especially lipid content. Based on post-egg-laying body composition and nutrient requirements for the production of one egg, it appeared that most females probably could have laid an additional egg almost solely from body reserves. Clutch size thus appears to be independent of body condition.

scholarly journals Body mass as an estimate of female body condition in a hibernating small mammal

2019 ◽  
Vol 133 (1) ◽  
pp. 34-42
Author(s):  
Caitlin P. Wells ◽  
James A. Wilson ◽  
Douglas A. Kelt ◽  
Dirk H. Van Vuren
Keyword(s):  
Body Mass ◽  
Body Condition ◽  
Condition Index ◽  
Ground Squirrels ◽  
Structural Size ◽  
Demographic Traits ◽  
Fat Stores ◽  
Total Body ◽  
Non Destructive ◽  
Reproduction Stage

In hibernating squirrels, the amount of energy stored as fat may influence several important demographic traits, but is difficult to quantify in living animals. Thus, several non-destructive indices of body condition are used, including simple indices that use body mass and scaled indices that correct body mass for structural size. However, the accuracy of these indices for hibernating squirrels is poorly known. We used measurements of total body electrical conductivity (TOBEC) from adult female Golden-mantled Ground Squirrels (Callospermophilus lateralis) to characterize body composition (lean mass versusfat mass) and condition (fat stores) at multiple stages in the circannual cycle. Body mass explained a high proportion of the variation in fat mass during the emergence and pre-hibernation stages, but less during the reproduction stage. Contrary to expectation, correcting for structural size did not markedly improve the condition index. Our results suggest that body mass is a good estimate of body condition during the periods of emergence and pre-hibernation fattening, and therefore may be useful to predict important components of fitness such as reproductive success and overwinter survival.

scholarly journals Variation in Foraging Behavior, Diet, and Time of Breeding of Florida Scrub-Jays in Suburban and Wildland Habitats

The Condor ◽  
2003 ◽  
Vol 105 (3) ◽  
pp. 515-527 ◽  
Author(s):  
Arthur L. Fleischer ◽  
Reed Bowman ◽  
Glen E. Woolfenden
Keyword(s):  
Food Consumption ◽  
Foraging Efficiency ◽  
Timing Of Breeding ◽  
Food Handling ◽  
Florida Scrub ◽  
Supplemental Food ◽  
Aphelocoma Coerulescens ◽  
Consumption Rates ◽  
Time Of Breeding ◽  
Ad Libitum

Abstract Supplemental food enables some birds to lay eggs earlier, perhaps by allowing birds to increase their energy intake or allocate energy from other activities to reproduction. We examined the relationships between prelaying behavior, food handling and consumption rates, and the timing of breeding of female Florida Scrub-Jays (Aphelocoma coerulescens) in suburban and wildland habitats. Scrub-jays in suburban habitats had access to ad libitum human-provided foods; wildland jays did not. During both years of this study, suburban scrub-jays bred earlier than their wildland counterparts. Wildland scrub-jays bred earlier in 1997 than in 1996, but the timing of breeding by suburban scrub-jays did not vary between years. Suburban scrub-jays spent less time foraging and more time perching than wildland jays. They handled more food per hour and per foraging hour, suggesting their foraging was more efficient. Despite this, food consumption rates did not differ between the two habitats. Neither time spent foraging or perching nor food consumption rates significantly influenced variation in time of breeding among individuals. Time of breeding was significantly influenced by site, year, and rate of food handling. Individuals that handled more food items per foraging hour, that is, those individuals that were most efficient, were the earliest breeders in both habitats. These results suggest that foraging efficiency increases with access to human-provided food and that resource predictability may be a perceptual cue for the appropriate timing of breeding. Variación en el Comportamiento de Forrajeo, la Dieta y la Época de Reproducción de Aphelocoma coerulescens en Ambientes Suburbanos y Silvestres Resumen. El alimento suplementario le permite a algunas aves poner huevos más temprano, quizás aumentando su ingestión de energía o permitiendo cambiar la asignación de energía de otras actividades a la reproducción. En este estudio examinamos las relaciones entre el comportamiento pre-postura, la manipulación de alimento y la tasa de consumo con la época de reproducción de hembras de la especie Aphelocoma coerulescens en ambientes suburbanos y silvestres. Las aves en ambientes suburbanos tenían acceso a alimento provisto ad libitum por humanos, mientras que las aves de las áreas silvestres no. Durante los dos años de estudio, las aves suburbanas se reprodujeron más temprano que las de las áreas silvestres. Las aves de áreas silvestres se reprodujeron más temprano en 1997 que en 1996, pero la época reproductiva de las aves de áreas suburbanas no varió entre años. Las aves suburbanas pasaron menos tiempo forrajeando y más tiempo perchadas que las de áreas silvestres, y además manipularon más alimento por hora y por hora de forrajeo, lo que sugiere que forrajearon más eficientemente. Sin embargo, las tasas de consumo de alimento no difirieron entre los dos ambientes. La variación entre individuos en el momento de la reproducción no fue influenciada significativamente por el tiempo invertido en forrajeo o descanso ni por la tasa de consumo de alimento, pero sí por el sitio, el año y la tasa de manipulación de alimento. Los individuos que manipularon más ítems alimenticios por sesión de forrajeo (los más eficientes), fueron los que se reprodujeron más temprano en ambos ambientes. Estos resultados sugieren que la eficiencia de forrajeo aumenta con el acceso a alimentos provistos por humanos y que la predecibilidad de los recursos podría ser percibida como una señal indicadora del momento de reproducción adecuado.

A body-condition index for ursids

2002 ◽  
Vol 80 (7) ◽  
pp. 1156-1161 ◽  
Author(s):  
Marc R.L Cattet ◽  
Nigel A Caulkett ◽  
Martyn E Obbard ◽  
Gordon B Stenhouse
Keyword(s):  
Body Size ◽  
Body Condition ◽  
Positive Relationship ◽  
Condition Index ◽  
Black Bears ◽  
Grizzly Bears ◽  
Polar Bears ◽  
Body Condition Index ◽  
Total Body Mass ◽  
Total Body

In this investigation a body-condition index (BCI) was developed for polar bears (Ursus maritimus), black bears (Ursus americanus), and grizzly bears (Ursus arctos), based on residuals from the regression of total body mass against a linear measure of size, straight-line body length (SLBL). Transformation of mass–length data from 1198 polar bears, 595 black bears, and 126 grizzly bears to natural logarithms resulted in a linear relationship between mass and length. However, the relationship in polar bears differed from that in black and grizzly bears. SLBL had a close positive relationship with skeletal (bone) mass in polar bears (n = 31) and black bears (n = 33), validating the use of SLBL as an accurate index of body size. There was no correlation between SLBL and BCI for polar bears (r = 0.005, p = 0.87, n = 1198) or for black bears and grizzly bears (r = 0.04, p = 0.30, n = 721), indicating that the BCI was independent of body size. The BCI had a close positive relationship with true body condition, measured as the standardized residual of the combined mass of fat and skeletal muscle against SLBL, in polar and black bears that were dissected to determine individual tissue masses. The BCI also had a close positive relationship with the standardized residual of fat mass against SLBL. Estimation of BCI values for polar bears, or for black bears and grizzly bears, is facilitated by prediction equations that require measurement of total body mass and SLBL for individual animals.

Assessing body condition in the platypus (Ornithorhynchus anatinus): a comparison of new and old methods

2016 ◽  
Vol 64 (6) ◽  
pp. 421 ◽  
Author(s):  
J. W. Macgregor ◽  
C. Holyoake ◽  
S. Munks ◽  
J. H. Connolly ◽  
I. D. Robertson ◽  
...  
Keyword(s):  
Body Condition ◽  
Total Body Length ◽  
Condition Index ◽  
Volume Index ◽  
Ultrasound Images ◽  
Body Condition Index ◽  
Current Standard ◽  
Cross Sectional ◽  
North West ◽  
Total Body

Body condition is an important aspect of the health of any animal. The current standard method of body condition assessment in the platypus is the tail volume index (TVI). Although the tail is the largest repository of fat in the platypus, the reliability of TVI has not been adequately demonstrated. The aims of this study were, first to assess performance of the TVI, and second, to develop and evaluate performance of new techniques for routine field assessment of platypus body condition. Morphometric data were collected under anaesthesia from 137 adult wild platypuses (74 males, 63 females) captured in north-west Tasmania; ultrasound images of tail fat were also collected from 100 of these individuals (54 males, 46 females). Three new indices for platypus body condition were identified. An objective tail fat index (Relative Tail Fat Volume: RTFVTBL) was developed, based on cross-sectional area measurements taken from detailed ultrasound images compared with total body length (TBL). Two body condition indices intended for routine field use were developed – one based on body mass (mb) and bill width (BW) (Body Condition Index; BCIBW), and the other based on a single linear ultrasonographic measurement of tail fat depth and BW (Relative Fat Depth; RFDBW). Results indicated that RFDBW outperforms TVI as an index of platypus tail fat. Further work, however, is needed to determine the relationship between tail fat and total body fat in the platypus before conclusions can be drawn about the effectiveness of BCIBW as a body condition index.

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