Energy limitations for spring migration and breeding: the case of brent geese Branta bernicla tracked by satellite telemetry to Svalbard and Greenland

Forskningsoutput: Kapitel i bok/rapport/Conference proceedingKonferenspaper i proceeding

Abstract

Brent geese were tracked by satellite telemetry from spring staging areas in Denmark to Arctic breeding areas in Svalbard and Greenland in 1997 and 2001. From estimated departure masses and carcass analysis we used flight mechnical theory to estimate maximum flight ranges of both sexes, and remaining stores of fat and protein upon arrival in females. Model predictions suggested that all birds but one exceptionally thin male could easily reach Svalbard, but that approximately one third of the males and half of the females would have problems with flying to Greenland. Nevertheless, some birds even flew longer than the models predicted. In addition, females predicted to be capable of making the flight to Greenland, were predicted to arrive almost lean of fat. This contradicts our expectation that these birds are capital breeders - that they depend on endogenous stores of fat and protein when initiating and incubating their eggs. We discuss how the Greenland breeding sub-population during 1985-1998 has been able to grow at the same rate as the sub-population breeding in Svalbard, despite the added flight distance of 700-1000 km, and despite the birds predicted shortage of fat stores on arrival. We suggest four hypotheses that alone or in combination could explain the discrepancy between model predictions and observations. These are that most birds: (1) refuel on stop-overs in Spitsbergen en route to Greenland; (2) pick favourable tail-winds enabling them to reduce flight costs; (3) fly in formation and thereby save energy; and/or (4) undergo gut atrophy immediately prior to departure, and use the nutrients mobilised by catabolism of the digestive system to build larger pectoral muscles. The latter option would both reduce their airframe fraction, and increase their fat and flight-muscle fractions, enabling them to fly longer. We conclude that the latter option seems less likely to operate in brent geese.

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Ekologi
  • Biologiska vetenskaper
Originalspråkengelska
Titel på värdpublikationOikos
FörlagWiley-Blackwell
Sidor426-445
Volym103
StatusPublished - 2003
PublikationskategoriForskning
Peer review utfördJa
EvenemangSymposium on Ecology of Long-Distance Movements - Lund, Sverige
Varaktighet: 2002 feb 212002 feb 24

Publikationsserier

Namn
Nummer2
Volym103
ISSN (tryckt)1600-0706
ISSN (elektroniskt)0030-1299

Konferens

KonferensSymposium on Ecology of Long-Distance Movements
LandSverige
OrtLund
Period2002/02/212002/02/24

Nedladdningar

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