Homeostasis of the Nonfat Components of Migrating Birds

Odum, Eugene P.; Rogers, David T.; Hicks, David L.

doi:10.1126/science.143.3610.1037

Cited by 180 publications

(52 citation statements)

References 8 publications

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“…Body mass often correlates well with fat reserves (e.g., white-fronted geese Anser albifrons; Johnson et al 1985). A ratio of body mass against a linear measure of body size is known to improve the correlation between the condition index and fat reserves (e.g., Odum et al 1964;Owen & Cook 1977). We used a body mass/ flipper length ratio index.…”

Section: Body Condition Of Penguinsmentioning

confidence: 99%

Prolonged foraging trips and egg desertion in little penguins (Eudyptula minor)

Numata

Davis

Renner

2000

New Zealand Journal of Zoology

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Penguins share incubation duties between the male and female of a pair. The one left on the nest must fast while its partner is foraging at sea. Nest attendance patterns during the incubation period reflect the way time is allocated between the conflicting demands of incubation and foraging. We conducted daily nest checks for little penguins (Eudyptula minor) at two localities in New Zealand (Motuara Island in the Marlborough Sounds and Oamaru, Otago) in the 1998/99 breeding season and found significant variation in nest attendance between the two areas. Penguins breeding at Motuara Island made significantly longer foraging trips and were in poorer body condition than those breeding at Oamaru. Foraging trip durations were significantly correlated with the body condition of birds at both areas: the poorer the condition, the longer the foraging trip durations. The increased risk of egg desertion observed at Motuara Island is probably a consequence of the prolonged foraging trips that limit the time available for incubation.

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Section: Body Condition Of Penguinsmentioning

confidence: 99%

Prolonged foraging trips and egg desertion in little penguins (Eudyptula minor)

Numata

Davis

Renner

2000

New Zealand Journal of Zoology

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“…Initially, it was thought that birds did not increase protein mass before migration (Odum et al, 1964); however, several studies have provided evidence to the contrary (Barlein and Gwinner, 1994;Fry et al, 1972;Lindstrom and Piersma, 1993;Piersma et al, 1999;Karasov and Pinshow, 1998). Most birds do not eat or drink in flight and thus must rely on their fat and protein stores as sources of energy and water (Bairlein and Gwinner, 1994;Karasov and Pinshow, 1998;Jenni and Jenni-Eiermann, 1998;Battley et al, 2000;Bordel and Haase, 2000).…”

Section: Introductionmentioning

confidence: 99%

Allocation of endogenous and dietary protein in the reconstitution of the gastrointestinal tract in migratory blackcaps at stopover sites

Muñoz‐Garcia

Aamidor

McCue

et al. 2012

Journal of Experimental Biology

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SUMMARYDuring migratory flight, the mass of the gastrointestinal tract (GIT) and its associated organs in small birds decreases in size by as much as 40%, compared with the preflight condition because of the catabolism of protein. At stopover sites, birds need 2-3days to rebuild their GIT so that they can restore body mass and fat reserves to continue migration. The source of protein used to rebuild the GIT may be exogenous (from food ingested) or endogenous (reallocated from other organs) or both. Because the relative contribution of these sources to rebuild the GIT of migratory birds is not yet known, we mimicked in-flight fasting and then re-feeding in two groups of blackcaps (Sylvia atricapilla), a Palearctic migratory passerine. The birds were fed a diet containing either 3% or 20% protein to simulate different refueling scenarios. During re-feeding, birds received known doses of 15 N-L-leucine before we measured the isotope concentrations in GIT and associated digestive organs and in locomotory muscles. We then quantified the extent to which blackcaps rebuilt their GIT with endogenous and/or dietary protein while refeeding after a fast. Our results indicate that blackcaps fed the low-protein diet incorporated less exogenous nitrogen into their tissues than birds fed the 20% protein diet. They also allocated relatively more exogenous protein to the GIT than to pectoral muscle than those birds re-fed with the high-protein diet. However, this compensation was not sufficient for birds eating the low-protein diet to rebuild their intestine at the same rate as the birds re-fed the high-protein diet. We concluded that blackcaps must choose stopover sites at which they can maximize protein intake to minimize the time it takes to rebuild their GIT and, thus, resume migration as soon as possible.

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“…This fuel was long held to be exclusively fat, with the non-fat component of the body remaining unchanged (Odum et al 1964). This`aircraft refuelling paradigm' treated birds like aeroplanes, having a constant structural mass and ¢lling and emptying only the fuel tanks.…”

Section: Introductionmentioning

confidence: 99%

Empirical evidence for differential organ reductions during trans–oceanic bird flight

Battley

Piersma

Dietz

et al. 2000

Proc. R. Soc. Lond. B

235

224

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Since the early 1960s it has been held that migrating birds deposit and use only fat as fuel during migratory £ight, with the non-fat portion of the body remaining homeostatic. Recent evidence from ¢eld studies has shown large changes in organ sizes in fuelling birds, and theory on fuel use suggests protein may be a necessary fuel during £ight. However, an absence of information on the body condition of migrants before and after a long £ight has hampered understanding of the dynamics of organs during sustained £ight. We studied body condition in a medium-sized shorebird, the great knot (Calidris tenuirostris), before and after a £ight of 5400 km from Australia to China during northward migration. Not only did these birds show the expected large reduction in fat content after migration, there was also a decrease in lean tissue mass, with signi¢cant decreases in seven organs. The reduction in functional components is re£ected in a lowering of the basal metabolic rate by 46%. Recent £ight models have tried to separate the`£exible' part of the body from the constant portion. Our results suggest that apart from brains and lungs no organs are homeostatic during long-distance £ight. Such organ reductions may be a crucial adaptation for long-distance £ight in birds.

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Homeostasis of the Nonfat Components of Migrating Birds

Cited by 180 publications

References 8 publications

Prolonged foraging trips and egg desertion in little penguins (Eudyptula minor)

Prolonged foraging trips and egg desertion in little penguins (Eudyptula minor)

Allocation of endogenous and dietary protein in the reconstitution of the gastrointestinal tract in migratory blackcaps at stopover sites

Empirical evidence for differential organ reductions during trans–oceanic bird flight

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