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

Urban Ecology ◽  
2008 ◽  
pp. 391-404 ◽  
Author(s):  
Stephan J. Schoech ◽  
Reed Bowman
Keyword(s):  
Timing Of Breeding ◽  
Florida Scrub ◽  
Aphelocoma Coerulescens ◽  
Differential Access

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 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.

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.

Florida Scrub-Jays (Aphelocoma coerulescens ) are Sentinels More When Well-Fed (Even with no Kin Nearby)

Ethology ◽  
2003 ◽  
Vol 109 (11) ◽  
pp. 895-903 ◽  
Author(s):  
Peter A. Bednekoff ◽  
Glen E. Woolfenden
Keyword(s):  
Florida Scrub ◽  
Aphelocoma Coerulescens

Florida Scrub-Jay (Aphelocoma coerulescens)

1996 ◽  
Author(s):  
Glen E. Woolfenden ◽  
John W. Fitzpatrick
Keyword(s):  
Florida Scrub ◽  
Aphelocoma Coerulescens
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