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Full-Text Articles in Poultry or Avian Science
Time-Activity And Energy Budgets Of Eared Grebes (Podiceps Nigricollis) At Salton Sea, Samantha San Francisco
Time-Activity And Energy Budgets Of Eared Grebes (Podiceps Nigricollis) At Salton Sea, Samantha San Francisco
Theses
Time-activity budgets have been a widely accepted way of approximating the daily energy expenditure of many species, including waterbirds. For this study, focal animal sampling was used to study Eared Grebes (Podiceps nigricollis) at their post-wintering stopover site, Salton Sea. Daylight time-activity budgets were converted to energy budgets using energy equivalents for diving, preening, swimming, and resting on water developed for Eared Grebes previously by H. I. Ellis (1994). Post-wintering Eared Grebes arrive at Salton Sea in waves at differing times in the spring. As a result, there can be individuals in a variety of physiological states during …
Plasma Metabolites Reveal Changes In Physiological State Of Eared Grebes (Podiceps Nigricollis) During Three Non-Migratory Periods, Allison A. Yoshida
Plasma Metabolites Reveal Changes In Physiological State Of Eared Grebes (Podiceps Nigricollis) During Three Non-Migratory Periods, Allison A. Yoshida
Theses
Energy storage and use during the annual cycle of migratory birds is dynamic especially during migration. However, considerable amounts of the annual cycle are spent not migrating, and the physiological state of birds during these non-migratory periods is not well understood. We compared plasma metabolites (TRIG, BUTY, URIC, GLY) in Eared Grebes (Podiceps nigricollis) residing at three important areas when they are not migrating: fall staging (postbreeding at Mono Lake, California), spring staging (pre-breeding at Great Salt Lake, Utah), and an extended stopover prior to spring staging (Salton Sea, California). Plasma metabolites were also measured in resting and active grebes …
Availability And Use Of Food Resources By Two Species Of Automolus (Aves, Furnariidae), Grace Patricia Servat-Valenzuela
Availability And Use Of Food Resources By Two Species Of Automolus (Aves, Furnariidae), Grace Patricia Servat-Valenzuela
Theses
Foraging specialization is one mechanism that has been hypothesized to promote species coexistence and, thus, higher bird species diversity in tropical forests. Dead-leaves suspended in vegetation above the forest floor constitute a focal substrate that may promote specialization (Rosenberg 1990a, b). In a study locality in Amazonia, Remsen and Parker (1984) reported 16 species of birds closely associated with this system. Therefore, it represents a microcosm of high diversity in tropical forests. As such, one natural question is how this substrate can support so many coexisting species, and at what level does specialization occur? In the present study, I address …