Dynamic energy and time budgets in hummingbirds: a study in Sephanoides sephaniodes

Lopez-Calleja, M. Victoria; Bozinovic, Francisco

doi:10.1016/s1095-6433(02)00263-5

Cited by 26 publications

(8 citation statements)

References 42 publications

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“…Our knowledge of hummingbird energy management strategies is based on a handful of studies in which either daily energy use was estimated from doubly labelled water (Powers & Conley, 1994;Powers & Nagy, 1988;Weathers & Stiles, 1989) or the energy budget was constructed from time or energy budgets from controlled metabolic measurements (Hainsworth, 1977;López-Calleja & Bozinovic, 2003;Stiles, 1971;Wolf & Hainsworth, 1971). In these studies, energetic state was estimated using mean values for energy expenditure from controlled measurements, but energetic flexibility over time and how energy expenditure varies under field conditions were not evaluated.…”

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confidence: 99%

Hummingbirds budget energy flexibly in response to changing resources

et al. 2019

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A key component of individual fitness is the ability to manage energy stores in response to variable resource availability, but because directly measuring energy budgets is difficult, daily energy management is rarely measured. Hummingbirds' energy management is relatively simple to model compared to other endotherms because they have high mass‐specific metabolic rates and store little fat. We determined which aspects of the hummingbird daily energy budget (i.e. thermoregulation, daytime activity costs, night‐time costs) change at the individual level in response to environmental variation. We found that daily energy expenditure varied threefold in two populations of broad‐billed hummingbirds (Cynanthus latirostris). Our model indicated the energy budget was distributed in the following proportions: daytime activity, 59% (range 22%–84%); thermoregulation, 23% (11%–32%); basal metabolism, 7% (3%–16%); and night‐time energy, 17% (6%–37%). Activity costs were higher at the hotter, homogeneous site and during the early‐wet season at both sites. Increased daily energy expenditure was related to decreased nectar availability and not significantly related to temperature or bird mass. With climate change, the indirect energetic costs of shifting resources could have greater impacts on endotherm energy budgets than direct costs such as thermoregulation. Increased foraging and activity costs could decrease the energy available to birds for somatic repair and reproduction, potentially causing differential fitness across seasons and sites. A free Plain Language Summary can be found within the Supporting Information of this article.

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confidence: 99%

Hummingbirds budget energy flexibly in response to changing resources

et al. 2019

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“…Bech, 1980;Cooper and Swanson, 1994;Maddocks and Geiser, 2000;McKechnie and Lovegrove, 2001;López-Calleja and Bozinovic, 2003;Lovegrove and Smith, 2003;McKechnie et al, 2007;Smit et al, 2008). However, this winter study showed that populations respond differently to acclimation, possibly as a result of persistent underlying physiological differences, or persistent effects of altitudinal acclimatization.…”

Section: Discussionmentioning

confidence: 68%

“…Published data often represents a single BMR or RMR value per species, regardless of altitudinal origin, or alternatively data from one population as a representative of an entire species (e.g. Bech, 1980;Cooper and Swanson, 1994;Boix-Hinzen and Lovegrove, 1998;Maddocks and Geiser, 2000;McKechnie and Lovegrove, 2001;Downs and Brown, 2002;López-Calleja and Bozinovic, 2003;Lovegrove and Smith, 2003;McKechnie et al, 2007), thus highlighting the need to acknowledge the role of phenotypic flexibility within a species.…”

Section: Introductionmentioning

confidence: 99%

Physiological variation in amethyst sunbirds (Chalcomitra amethystina) over an altitudinal gradient in winter

Lindsay

Downs

Brown

2009

Journal of Experimental Biology

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SUMMARYFlexibility of metabolic rates within a species allows for the colonization of different habitats along an altitudinal and thus temperature gradient. The distribution range of amethyst sunbirds (Chalcomitra amethystina) within southern Africa includes an altitudinal gradient from the Drakensberg to the coast of KwaZulu-Natal. We expected that over this altitudinal gradient amethyst sunbirds would exhibit variation in winter metabolic rates, particularly basal metabolic rates (BMR) and resting metabolic rate (RMR) pre-and post-acclimation. Sunbirds from three locations, Underberg (1553 m above sea level; asl), Howick (1075 m asl) and Oribi Gorge (541 m asl) were used for this study. Upon capture, metabolic rate was measured indirectly by quantifying oxygen consumption (V O2 ) using flow-through respirometry, at 5 and 25°C. Birds were then acclimated at 25°C for 6 weeks on a 12 h:12 h L:D cycle. V O2 was measured post-acclimation at eight different temperatures (15, 5, 10, 20, 30, 28, 25 and 33°C). We found little variation in winter V O2 between individuals from the same locality, whereas significant variation was observed in V O2 at the same temperatures between individuals from the different localities and thus between altitudes. In particular, winter BMR decreased significantly with decreasing altitude post-acclimation. This study emphasizes the need to understand plasticity/flexibility in metabolic rates and to acknowledge altitudinal differences within a species, to make accurate predictions about the thermal physiology of a species and its responses to changes in ambient temperatures.

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“…Kidney hypertrophy has been documented in S. sephaniodes when exposed to chronic cold environments and diluted diets of high protein concentration (López-Calleja and Bozinovic, 2003), and in rodents confronted with high levels of protein in their diets (Klahr, 1989;Hammond and Janes, 1998).…”

Section: Morphological Effectsmentioning

confidence: 99%

“…Several studies have demonstrated that hummingbirds regulate their energy balance on a daily scale and that any energy imbalance immediately affects their behavior and body mass maintenance (Hainsworth, 1978;Wolf and Hainsworth, 1980;Calder et al, 1990; Martínez del Río and Karasov, 1990;McWhorter and López-Calleja, 2000;Fernández et al, 2002;López-Calleja and Bozinovic, 2003). Nevertheless, few studies have examined the protein balance of hummingbirds over a longer period than a daily time scale.…”

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confidence: 99%

The integration of energy and nitrogen balance in the hummingbirdSephanoides sephaniodes

Lopez-Calleja

Fernández

Bozinovic

2003

Journal of Experimental Biology

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SUMMARYFloral nectars are rich in energy but contain only traces of amino acids,and it has been hypothesized that arthropods may be an important source of energy and amino acids for hummingbirds. We studied the nitrogen requirements of hummingbirds as well as how they use small arthropods to satisfy their nitrogen and energy requirements and how organ mass varies with nitrogen intake. Non-reproductive green-backed firecrowns Sephanoides sephaniodes were maintained for 10 days on diets containing 0%, 0.96%,1.82%, 4.11% and 11.1% nitrogen (dry-matter basis). A second group of individuals were fed with varying amounts of nitrogen-free nectar supplemented with fruit flies. Finally, non-reproductive hummingbirds were captured as a control group for analysis of organ mass and size as well as fat content.The maintenance nitrogen requirement of green-backed firecrowns determined by regression was 1.42 mg N day-1, yet they required nearly 10 mg N day-1 to maintain body mass. When arthropods were available, we observed that hummingbirds required approximately 150 fruit flies to maintain body mass, which corresponds to a 5% nitrogen diet. Interestingly, when nectar was restricted (to 4 ml day-1), or was absent, arthropods alone were not able to satisfy the body mass balance requirements of hummingbirds,suggesting that arthropods are not adequate as an energy source. In the group offered an 11.1% nitrogen diet, the size and surface of the small intestine,and liver and kidney mass increased in comparison with the control group(non-reproductive field hummingbirds) or the nitrogen-free group, suggesting a nitrogen overload. Our results are in agreement with other studies showing low nitrogen requirements by nectarivores. An important point to stress is that nitrogen digestibility declined in the 11.1% nitrogen diet, which strongly supports our nitrogen absorption saturation hypothesis.

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Dynamic energy and time budgets in hummingbirds: a study in Sephanoides sephaniodes

Cited by 26 publications

References 42 publications

Hummingbirds budget energy flexibly in response to changing resources

Hummingbirds budget energy flexibly in response to changing resources

Physiological variation in amethyst sunbirds (Chalcomitra amethystina) over an altitudinal gradient in winter

The integration of energy and nitrogen balance in the hummingbirdSephanoides sephaniodes

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