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Accueil du site → Doctorat → États-Unis → 1995 → Physiological ecology of northern bobwhite and scaled quail reproduction

Texas Tech University (1995)

Physiological ecology of northern bobwhite and scaled quail reproduction

Giuliano, William M.

Titre : Physiological ecology of northern bobwhite and scaled quail reproduction

Auteur : Giuliano, William M.

Université de soutenance : Texas Tech University

Grade : Doctor of Philosophy (PhD) 1995

Résumé
Periodic "booms and busts" exhibited by populations of gallinaceous birds, including northern bobwhite (Colinus virginianus) and scaled quail (Callipepla squamata), appear to be due to reproductive failures associated with drought. Droughts have the potential to affect quail reproduction via direct effects of water-deprivation and indirectly by reducing the availability of succulent and nutritious foods such as invertebrates Using a series of studies, I examined the relationships among water-deprivation, nutrition, drought, and northern bobwhite and scaled quail reproduction and abundance. Protein and energy deficiencies led to declines in northern bobwhite and scaled quail body and ovary mass, and egg production, but did not affect egg mass of either species. While body mass and reproduction of both species were affected by protein and energy deficiencies, scaled quail were less impacted. Additionally, dietary energy was relatively more important to mass stasis and reproduction than protein. Scaled quail had superior osmoregulatory abilities and were better adapted to simulated drought conditions than northern bobwhite. Additionally, the two species had very different responses to simulated drought. Under normal breeding season (i.e., access to ad libitum water) conditions, northern bobwhite gained more body mass and produced more, but smaller eggs than scaled quail. Under simulated drought conditions, northern bobwhite lost more body mass, but had more hens laying and a higher rate of egg production, compared with scaled quail. My data suggest that under normal conditions and during periods of drought, northern bobwhite are more r-selected, allocating more resources to reproduction than to body maintenance, while scaled quail are more Kseleaed, apparently foregoing reproduction in favor of body maintenance Serum osmolality, but not progesterone and corticosterone, was a good indicator of water-restriction induced reproductive declines in northern bobwhite and scaled quail A diet of invertebrates in the absence of water could provide male but not female quail with enough water to maintain body mass and reproductive function. Field data suggests that breeding season rainfall affected northern bobwhite, but not scaled quail breeding success. Breeding season rainfall also affected abundance of both species. Drought, directly via water-deprivation or indirectly via macronutrient deficiencies, affects northern bobwhite and scaled quail reproduction and abundance. Quail management should focus on providing succulent and nutritious foods such as invertebrates and establishment of permanent water sources. Managers should also consider harvesting scaled quail more conservatively than northern bobwhite because they are more K-selected. Protein and energy deficiencies led to declines in northem bobwhite and scaled quail body and ovary mass, and egg production, but did not affect egg mass of either species. While body mass and reproduction of both species were affected by protein and energy deficiencies, scaled quail were less impacted. Additionally, dietary energy was relatively more important to mass stasis and reproduction than protein.

Mots Clés : Northern bobwhite — Scaled quail — Quails

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