Load size and energy delivery in birds feeding nestlings: Constraints on and alternative strategies to energy-maximization

Fagerström, Torbjörn; Moreno, Juan; Carlson, Allan

doi:10.1007/bf00378222

Cited by 31 publications

(11 citation statements)

References 19 publications

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“…Fagerstr6m et al (1983) showed in a theoretical model that the receptive and digestive capacity of the nestlings during early phases of development would impose a constraint on the foraging capacity of the parents by forcing them to collect and deliver loads of smaller size than would be energetically optimal. Fagerstr6m et al (1983) showed in a theoretical model that the receptive and digestive capacity of the nestlings during early phases of development would impose a constraint on the foraging capacity of the parents by forcing them to collect and deliver loads of smaller size than would be energetically optimal.…”

Section: Discussionmentioning

confidence: 99%

Parental Care in the Wheatear Oenanthe oenanthe: Effects of Nestling Age and Brood Size

Moreno¹

1987

Ornis Scandinavica

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Wiley and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Ornis Scandinavica. Moreno, J. 1987. Parental care in the Wheatear Oenanthe oenanthe: effects of nestling age and brood size. -Ornis Scand. 18: 291-301.Changes in different aspects of parental care of Wheatears with nestling age and brood size were studied over 4 yr in two Swedish breeding populations. Some broods were enlarged or reduced to increase the range of observed brood sizes. The proportion of time females spent brooding decreased with nestling age until day 8, but the mean duration of brooding bouts did not, implying that females reduced the frequency of brooding bouts as homeothermic capacity of the young improved. Females reduced mean bout duration with brood size but not the total time spent brooding. The different effects of nestling age and brood size, and the negative effect of females' feeding rates on brooding commitment suggest that the food requirements of the young may affect female brooding behaviour independently of the homeothermic capacity of the young. Feeding rates of males and females increased similarly throughout the nestling period and reached a plateau from day 9 to fledging at about day 14. Load size and prey size increased with nestling age, and the proportions of spiders and small caterpillars in the diet of nestlings decreased. Males delivered larger loads than females. The relationship between feeding rates and brood size during the plateau phase differed depending on whether manipulated broods were included in the analysis or not. For unmanipulated broods, feeding rates did not increase with brood size and there was thus a decrease in feeding rates per nestling with brood size. When including manipulated broods in the analysis, there was a decelerating positive relationship of feeding rates with brood size. When removing the small broods, no decrease in feeding rates per nestling with brood size was found in the joint analysis of all broods. Brood manipulations led to changes in feeding rates with respect to the normal pattern observed. Future studies of parental care should consider these effects of manipulations before deriving any definitive conclusion about brood size effects.

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Section: Discussionmentioning

confidence: 99%

Parental Care in the Wheatear Oenanthe oenanthe: Effects of Nestling Age and Brood Size

Moreno¹

1987

Ornis Scandinavica

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“…We consider 3 currencies (reviewed by Houston 1987), although others (e.g., Fagerstrom et al 1983) may also be appropriate. The life span of honey bees (Apis meIlifera), at least, appears to be limited by energetic expenditure (Wolf and Schmid-Hempel 1989), leading to the prediction that bees should be sensitive to the diminution in their life span caused by energetic expenditures while foraging.…”

Section: The Hypothesesmentioning

confidence: 99%

Colony energy requirements affect the foraging currency of bumble bees

Cartar

Dill

1990

Behav Ecol Sociobiol

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This study examines whether the foraging behavior of worker bumble bees (Bombus: Apidae) collecting nectar on inflorescences of seablush (Plectritis congesta: Valerianaceae) is affected by colony energetic requirements, which were experimentally manipulated either by adding sucrose solution to honey pots or by removing virtually all available nectar from the pots. The competing hypotheses tested were: (1) no change; energetic requirements do not affect behavior, since there is a single best way to collect food in a given environment; (2) energetic currency; the energetic currency maximized by foragers changes according to colony energetic condition, with nectar-depletion causing a shift from maximizing long-term productivity to maximizing immediate energetic gain, thereby de-emphasizing energetic costs; and (3) predation; foragers devalue risk of predation as risk of starvation increaes, with colony nectar-depletion causing foragers to be less predation riskaverse in order to increase immediate energetic gain. Relative to when their colony energy reserves were enhanced, foragers from nectar-depleted colonies selected smaller inflorescences, visited fewer flowers per inflorescence, probed flowers at a higher rate while on each inflorescence, and walked between inflorescences less often, thereby spending a greater proportion of their foraging trip in flight. These behaviors increased a bee's energetic costs while foraging, and should also have increased its immediate energetic gains, allowing rejection of the no change hypothesis. Predictions of the predation hypothesis were generally not supported, and our results best support the energetic currency hypothesis. Foraging currency of bumble bees therefore appears to be a function of colony energetic state.Many of the early successful tests of foraging theory used nectar-collecting bumble bees (Pyke 1979(Pyke , 1980Hodges 1981;Best and Bierzychudek 1982). These tests Offprint requests to: R.V. Cartar addressed the problem of when a bee should move from one inflorescence to the next, given that the nectar rewards on inflorescences decrease in a predictable manner. Inflorescence-departure decisions were found to be predicted by the marginal value theorem (Charnov 1976), and the currency maximized by these bees appeared to be the rate of net energy intake.While the goal of net rate maximization is probably accurate in a general sense (i.e., over the long term), recent work suggests that it is not necessarily adequate as a short term currency for foragers (Stephens in press). The findings of risk-sensitivity (e.g. Caraco et al. 1980) and time discounting (Kagel et al. 1986) cannot be explained in terms of net rate maximizing. More recent approaches to foraging theory explicitly recognize tradeoffs between foraging and other activities, and the effects of time horizons and the forager's state on foraging behavior (e.g., McNamara and Houston 1986). Net rate maximizing, then, can be viewed as simply a special case subsumed within a general theoretical framework relating for...

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“…The foraging behavior of adult birds is commonly influenced by the development of their nestlings (Fagerström et al 1983). Furthermore, by influencing adult foraging patterns, nutritional requirements of nestlings may influence colony site selection .…”

Section: Discussionmentioning

confidence: 99%

Movement Patterns of Adult Laughing GullsLarus atricillaDuring the Nesting Season

Dosch

2003

Acta Ornithologica

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Load size and energy delivery in birds feeding nestlings: Constraints on and alternative strategies to energy-maximization

Cited by 31 publications

References 19 publications

Parental Care in the Wheatear Oenanthe oenanthe: Effects of Nestling Age and Brood Size

Parental Care in the Wheatear Oenanthe oenanthe: Effects of Nestling Age and Brood Size

Colony energy requirements affect the foraging currency of bumble bees

Movement Patterns of Adult Laughing GullsLarus atricillaDuring the Nesting Season

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