Body mass loss amongst moulting Pochard Aythya ferina and Tufted Duck A. fuligula at Abberton Reservoir, South East England

• Published in: Journal of Ornithology
• Language: English
• Published: Springer-Verlag 2012
• Subjects: Wing moult; Moult migration; Phenotypic plasticity; Fat stores; Energy budget; Dee; National Environmental Research Institute
• Online Access: http://hdl.handle.net/2262/61884; https://doi.org/10.1007/s10336-011-0656-7

Abstract We assessed the contribution of endogenous fat stores to meeting energetic needs during the flightless moult period in Pochard and Tufted Duck by regressing mass on the progression of wing moult, as measured by primary length. Pochard lost between 22.1% (males) and 24.2% (females) of body mass and female Tufted Duck 12.2% during wing moult at Abberton Reservoir, Essex. Based on a 27-day flightless period, Pochard lost on average 8.3?8.4 g per day and Tufted Duck 3.2?3.4 g per day, presumably due to fat expenditure. Assuming the daily energy expenditure (DEE) to be 1.7? the basal metabolic rate (BMR), the contribution from burning endogenous fat equated to 37?40% of Pochard and 19?20% of Tufted Duck DEE during remiges moult. One frequently re-trapped female Pochard expended fat stores that almost fulfilled her entire energetic requirements during moult if she rested and did not feed for most of the moult. These results confirm that Pochard and Tufted Duck accumulate fat stores that help to meet energetic needs during the flightless wing moult period. This endogenous source of energy may free them to exploit habitats that are safe from predation but which may not fully supply the energetic needs of moulting ducks from exogenous sources. Zusammenfassung Wir erfassten den Anteil endogener Fettreserven an der Bewaltigung energetischer Anforderungen wahrend der mauserbedingten Flugunfahigkeit bei Tafel- und Reiherenten durch Regression der Masse gegen das Fortschreiten der Flugelmauser, gemessen an der Lange der Handschwingen. Am Abberton Reservoir in Essex verloren Tafelenten zwischen 22,1% (Mannchen) and 24,2% (Weibchen) Korpermasse, wahrend Reiherentenweibchen 12,2% Korpermasse verloren. Gemessen an einer flugunfahigen Periode von 27 Tagen verloren Tafelenten durchschnittlich 8,3?8,4 g pro Tag und Reiherenten 3,2?3,4 g pro Tag, was vermutlich auf die Nutzung von Fettdepots zuruckzufuhren ist. Unter der Annahme eines taglichen Energiebedarfs (DEE) von 1,7? Grundstoffwechselrate (BMR) betragt der Verbrauch von endogenen Fettreserven wahrend der Mauser der Flugfedern 37?40% des DEE bei Tafelenten und 19?20% bei Reiherenten. Eine mehrfach wieder gefangene weibliche Tafelente verbrauchte Fettreserven, die allein nahezu ihren gesamten Energiebedarf wahrend der Mauser decken konnten, sofern sie rastet und nicht nach Futter sucht. Diese Ergebnisse bestatigen, dass Tafel- und Reiherenten Fettreserven anlegen, die ihnen helfen, die flugunfahige Zeit der Mauser zu uberbrucken. Diese endogenen Energiereserven erlauben es ihnen Habitate aufzusuchen, die sicher vor Fressfeinden sind, aber nicht ausreichend Futterquellen bieten, um den Energiebedarf wahrend der Mauser zu decken. phone: [phone] (Fox, Anthony D.) [e-mail] (Fox, Anthony D.) Department of Wildlife Ecology and Biodiversity, National Environmental Research Institute, Aarhus University - Gren?vej 14 - 8410 - R?nde - DENMARK (Fox, Anthony D.) The Wildfowl and Wetlands Trust - GL2 7BT - Slimbridge - UNITED KINGDOM (King, Roy) DENMARK UNITED KINGDOM Registration: 2011-01-11 Received: 2010-07-01 Revised: 2010-12-22 Accepted: 2011-01-11 ePublished: 2011-01-28