Body Condition in the Eurasian Woodcock Wintering in the West of France: Practical Study for Wildlife Management during Cold Spells
Abstract
The Eurasian woodcock (Scolopax rusticola) is one of the most widespread species of the Scolopax genus in temperate regions. However, population levels can be greatly affected by harsh cold spells that led woodcocks to starve by exhaustion of their body fuels.
To better understand the vulnerability of woodcocks to such climatic conditions it is of a major importance to determine the amount of their body reserves (both lipids and proteins) throughout the wintering season. This was performed on 55 individuals collected by hunters in the western part of France during two consecutive winters under mild weather conditions. Body reserves, that can be mobilised, were determined as the difference between the total amount of lipids and proteins minus the values obtained on starved individuals found dead during previous cold spells.
Overall, body reserves did not significantly change over both winters (p > 0.40), the maximal mean value (1539 ± 117 kJ) being however reached in January. Storing body fuels would not adversely affect wing and power loading, suggesting that the amount of body reserves would agree with the "starvation-predation trade-off". If woodcocks sit through a cold spell, their mean survival time (or fasting endurance) would be 6.5 ± 0.5 days; 25 to 40% of the birds would have a life expectancy of 7-9 days, and about 8 to17% less than 5 days. On the contrary, if woodcocks immediately leave their wintering quarter, they would be able to perform a trip of 740 ± 50 km, 20 to 40% of the woodcocks being able to fly over 750 km. Body mass explains only 47 to 57% of the fasting endurance and flight autonomy variations, and therefore we recommend a further carcass analysis to accurately estimate body condition.
These results underscore the suitability of determining the state of body reserves for practical cases of population management and hunting policy during cold spells.
Keywords
Body fuels; cold spell; fasting; flight autonomy; strategy; survival.References
1. Allou, J., Chusseau, J.P., Hameaux, S., Mallie, T. & Veiga, J. 1988. Une étude de líimpact local de la vague de froid de janvier 1987 sur quelques espËces de líavifaune migratrice terrestre (Turdus iliacus, Turdus philomelos, Scolopax rusticola) en un point de la presquíÓle du Cap-Ferret (Gironde). (A study on the impact of the cold spell that occurred in January 1987 on some land migratory bird species (Turdus iliacus, Turdus philomelos, Scolopax rusticola) on the Cap-Ferret Island (Gironde South-Western Atlantic coast-France)). Bulletin Mensuel ONC 122 : 13-16.
2. Tavecchia G., Pradel R., Gossman E, Bastat C., Ferrand Y. & Lebreton, J.D. 2002. Temporal variation in annual survival probability of the Eurasian woodcock Scolopax rusticola wintering in France. Wildlife Biol. 8 : 21-30.
3. Boos, M. 2000. Modification des réserves énergétiques corporelles du canard colvert (Anas platyrhynchos) et de la bécasse des bois (Scolopax rusticola) au cours de leur hivernage : aspects fonctionnels liés á la biologie de ces espËces et aux conditions du milieu. (Changes in body energetic reserves in the Mallard (Anas platyrhynchos) and the Eurasian Woodcock (Scolopax rusticola) during their wintering stage: functional characteristics related to the biology of these species and habitat conditions). PhD Thesis, University of Strasbourg.
4. Duriez, O. 2003. Stratégies individuelles díhivernages chez la Bécasse des bois (Scolopax rusticola): compromis énergétiques pour la sélection de líhabitat. (Individual wintering strategies in the Eurasian Woodcock (Scolopax rusticola): energetic compromises for the habitat selection). PhD Thesis, University of Paris.
5. Robin, J-P., Boos, M., Gossmann, F., Zorn, T., Le Maho, Y. & Groscolas, R. 1999. Cold spell sensitivity of the woodcock (scolopax rusticola). In: ThomaÔdes C. & Kypridemos, N. (eds.), proceedings of 24th international congress of the international union of game biologists I.U.G.B, Thessalonique, pp 259-266.
6. Cherel, Y. & Groscolas, R. 1999. Relationships between nutrient storage and nutrient utilisation in long-term fasting birds and mammals. In: Adams, N.J. & Slotow, R.H. (eds.), Proceedings of the 22nd International Ornithological Congress, Durban, Johannesburg, BirdLife South Africa, pp. 17-34.
7. Dugan, P.J., Evans, P.R., Goodyer, L.R. & Davidson, N.C. 1981. Winter fat reserves in Shorebirds: disturbance of regulated levels by severe weather conditions. Ibis 123: 359-363.
doi: 10.1111/j.1474-919X.1981.tb04040.x.
8. Davidson, N.C. 1982. Changes in the body-condition of redshanks during mild winters: an ability to regulate reserves? Ringing & Migration 4: 51-62.
9. Reinecke, K. J., Stone, T. L. & Owen, R.B.Jr. 1982. Seasonal carcass composition and energy balance of female black ducks in Maine. Condor 84: 420-426.
doi: 10.2307/1367447.
10. Smith, L.M. & Sheeley, D.G. 1993. Factors affecting condition of northern pintails wintering in the Southern High Plains. J. Wildl. Manage. 57: 62-71.
doi: 10.2307/3809001.
11. Biebach, H. 1996. Energetics of winter and migratory fattening. In: Carrey, C. (ed.), Avian energetics and nutritional ecology. Chapman and Hall, New York, pp. 280-323.
12. Fadat, C. 1989. Modalités zoogéographiques de la migration et de líhivernage en France de la bécasse des bois (Scolopax rusticola L.) et gestion cynégétique des ces populations. (Zoogeographic patterns on migration and wintering of the Eurasian Woodcock (Scolopax rusticola L.) in France and the hunting management of these populations). PhD Thesis. University of Montpellier.
13. Pennycuick, C.J. 1975. Mechanics of flight. In: Farner, D. S. & King, J. R. (eds.), Avian biology, vol 5. Acad. Press Inc, London , pp. 1-75.
14. Boos, M., Boidot, J.P., Gossmann, F., Dutertre, B., Bourse, J., Wulgué, A. & Robin, J-P. 2001. Determining body fuels and body condition of wintering woodcocks (Scolopax rusticola). In: proccedings of the 25th international congress of the international union of game biologists I.U.G.B, Lemesos, Cyprus, pp. 79-80.
15. Blem, C.R. 1990. Avian energy storage. Current Ornithology 7: 59-113.
16. Bennett, P.M. & Harvey, P.H. 1987. Active and resting metabolism in birds: allometry, phylogeny, and ecology. J. Zool. Lond. 213: 327-363.
17. Norberg, U.M. 1996. Energetics of flight, In: Carrey, C. (ed.), Avian energetics and nutritional ecology. Chapman and Hall, New York, pp. 199-249.
18. Campbell, R.R. et J.F. Leatherland. 1980. Estimating body protein and fat from water content in lesser snow geese. J. Wildl. Manage. 44: 438-446.
doi: 10.2307/3807975.
19. Davidson, N.C. 1981. Survival of shorebirds (Charadrii) during severe weather: the role of nutritional reserves. In Jones, N.V. & Wolff, W.J. (eds.), Feeding and survival strategies of estuarine organisms, Plenum press New-York, London, pp. 231-250.
20. Hepp, G.R. 1986. Effects of body weight and age on the time of pairing of American Black Ducks. Auk 103: 477-484.
21. Witter, M.S. & Cuthill, I.C. 1993. The ecological costs of avian fat storage. Philos. T. Roy. Soc. B 340: 73-92.
doi: 10.1098/rstb.1993.0050.
22. Witter, M.K., Cuthill, I.C. & Bonser, R.H.C. 1994. Experimental investigations of mass-dependant predation risk in the European starling, Sturnus vulgaris. Anim. Behav. 48: 201-222.
doi: 10.1006/anbe.1994.1227.
23. Gosler, A.G., Greenwood, J.J.D. & Perrins, C. 1995. Predation risk and the cost of being fat. Nature 377: 621-623.
doi: 10.1038/377621a0.
24. Ydenberg, R.C., Butler, R.W., Lank, D.B., Smith, B.D. & Ireland, J. 2004. Western sandpipers have altered migration tactics as peregrine falcon populations have recovered. P. Roy. Soc. Lond. B Bio. 271: 1263-1269.
25. Gossmann, F. & Ferrand, Y.. 1998. Impact of the 1996/1997 cold spell on woodcock in France based on ring recoveries. In: Kalchreuter, H. (ed.), Proceedings of the fifth European woodcock and snipe workshop. Wetland International Global series n∞4, pp. 37-39.
26. Robin, J-P., Boucontet, L., Chillet, P. & Groscolas, R. 1998. Behavioral changes in fasting emperor penguins: evidence for "refeeding signal" linked to metabolic shift. Am. J. Physiol. 274: R746-753.
27. Piersma, T. & Poot. M. 1993. Where waders may parallel penguins: spontaneous increase in locomotor activity triggered by fat depletion in a voluntarily fasting knot. Ardea 81: 1-8.




