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Biphasic Mass Gain in Migrant Hummingbirds: Body Composition Changes, Torpor, and Ecological Significance
Body mass of migrant Rufous Hummingbirds on refueling stopovers increased on average from 3.2 to 4.6 g over a period ranging from several days to 3 wk, suggesting that nocturnal torpor facilitated lipid deposition. Expand
Threshold Model of Feeding Territoriality and Test with a Hawaiian Honeycreeper
A model predicting that in nectarivorous birds territorial behavior will occur above a lower threshold of nectar productivity in a foraging area and disappear above an upper threshold and decline of efficiency of territorial exclusiveness is predicted. Expand
Food abundance and territoriality: to defend or not to defend?
It is shown that animals potentially can assess whether or not food supply is limited in the surrounding region by sampling and comparing standing crops in defended and undefended situations. Expand
A new function for torpor: fat conservation in a wild migrant hummingbird
Monitoring of the daily energy state of hummingbirds in the field showed that migrant hummingbirds may use torpor when they are very fat and not presently energetically stressed, indicating a mechanism to conserve the energy stored for later use on migration. Expand
Food Passage and Intestinal Nutrient Absorption in Hummingbirds
Etude de l'adaptation de la physiologie digestive permettant a Selasphorus rufus et Calypte anna d'absorption des aliments sucres rapidement et efficacement
Plant‐Pollinator Interactions in Hawaii: Pollination Energetics of Metrosideros Collina (Myrtaceae)
Fruit—set was much higher in red—flowered individuals when birds were allowed to use inflorescences than when only insects used them, apparently caused by partial self—incompatibility, such that maximal fruit—set occurs only with outbreeding, the primary agents of which are the birds. Expand
Digestive physiology is a determinant of foraging bout frequency in hummingbirds
It is found that hummingbird intestine has the highest active glucose transport rate and lowest passive glucose permeability reported for any vertebrate, and a new method for measuring crop-emptying times is presented. Expand
Weight gain and adjustment of feeding territory size in migrant hummingbirds.
The results suggest, although not conclusively, that these birds are selected to maximize their rate of weight gain on each stopover prior to resuming migration. Expand
Interference asymmetries among age-sex classes of rufous hummingbirds during migratory stopovers
SummaryThree age-sex classes of rufous hummingbirds (Selasphorus rufus) overlap temporally and defend feeding territories during migratory stopovers in the Sierra Nevada of California. We demonstrateExpand
Early growth of native and exotic trees planted on degraded tropical pasture
Assessment of the potential of two exotic and five native tree species in reestablishing trees to degraded land in the humid tropics of southern Costa Rica found that Pinus tecunumanii was the outstanding performer with best growth and survival among all blocks. Expand