BIRD
More about the Programme
Future studies on bird migration have to take much greater advantage of comparative and integrated studies, combining theory, field observations, and laboratory studies, and linking, physics, physiology, ecology and behaviour. Migration is a general biological phenomenon, not simply a trait characteristic of a particular taxon. The characterization of migration must consider the physiological mechanisms underlying migratory behaviour, the ecological consequences of that behaviour, and how those consequences guide evolution.
The dynamic interplay between theoretical development and empirical work on physics, physiology and ecology, is a fine example of highly successful use of the optimality approach in biology, and it will evaluate our understanding of the evolutionary possibilities and limitations in bird migration, and of the adaptive significance of migratory habits as well as the migrants flexibility to respond to human alterations of ecological systems.
This Programme aims to initiate the integration of various sub-disciplines, such as ecology, physiology, behaviour and genetics, thereby earning a much better understanding of the bird migration syndrome. It aims to form a forum for more trans-disciplinary studies in bird migration.
The goals
To understand fuelling is crucial for understanding the migration strategies and the selective forces and constraints acting upon them and for taking appropraite conservation measures. Therefore, the programme aims to give particular emphasis to studies of the ecology and physiology of fuelling, as the basis for the evaluation of the existing theory and models, and practical application in conservation.
The proposed goals will be achieved by a combination of field and laboratory studies, and are based on existing models on optimal bird migration and their predictions (Alerstam & Lindström 1990, Weber & Houston 1997).
The basic hypotheses
Alerstam & Lindström (1990) formulated three basic hypotheses derived from the model of optimal migration:
- Birds trying to minimize time (= maximize migration speed) on migration should be sensitive to the rate of fuel deposition. The departure fuel load should correlate positively with the rate of fuel deposition. Birds which decide with respect to time-minimization should leave a stop-over site for further migration with maximum fuel loads.
In such time-selected migrants, birds at northern sites should show higher fuel reserves than at more southern sites in autumn, and opposite in spring, and fuel mass of late migrating cohorts should be higher than of early migrants.
In time-selected migration, a risk-prone foraging during fuel deposition is predicted with preference of variable food rewards, hence a wider spectrum of food.
In birds minimizing cost of transport (energy-minimization; energy economy) the departure fuel load should be independent of the rate of fuel deposition. These birds should travel with as low extra weight as possible.
In energy-selected migration, risk-proneness could be advantageous if the expected energy budget for the migratory journey is insufficient. Otherwise, risk aversion may increase the probability of avoiding shortfalls.
Birds trying to minimize mortality (predator-minimization) should adjust their decisions to stay at or leave a stopover site with respect to predator-load (risk) of a particular site. To militate against mortality risks birds should be inclined to depart with smaller fuel reserves than is optimal in time-selected migrants. Birds in predation-selected migration should switch from stopover sites or habitats with a high rate of fuel deposition but also high predation risk to more protected sites with a smaller rate of fuelling according to which sites or habitats provide the minimium possible ratio between mortailty and the speed of migration.
Basic questions to be addressed
There are a number of constraints on the optimal decision due to recurring local environmental (extrinsic) cues (e.g. food distribution, abundance and availability, feeding conditions, weather, intra- and interspecific competition, predation hazard) and intrinsic cues (e.g. age, sex, physiological capabilities, digestive capacities, parasite load, endogenuous migratory time program).
Consequently, the birds response to variabality in resources is of particular interest to reveal the stopover decisions, and the trade-offs between time-, energy-, or predation-selected migration, and the adaptive significance of the various migratory habits.
To unravel these complex relationships, the following basic questions need to be addressed:
- Which are the conditions (body mass, fat score, biochemical status) of birds at arrival and at departure from stopover? Are there differences between age classes, or sexes?
- Which are the conditions (habitat, food, shelter, etc.) required for fuelling?
- Are these requirements variable in space and time (e.g. along the migratory route; autumn vs spring)?
- Which are the constraints (food, weather, predators, competitors, parasites) influencing the timing and the extent of migratory fuel accumulation at a stopover site
- Which fuels (fat, protein) are accumulated and to what extent?
- How does the daily rate of fuelling affect the birds decision to stay or fly?
The complete scientific proposal approved by the ESF Executive Council for launching from 1 January 2000 is available, using Adobe Acrobat, here (PDF 65.9 KB).
News/current status
The final deadline for applications for travel grants for visits between institutes in different European countries from one week up to six months (in exceptional cases up to 12 months) was 31 March 2004, for visits to start from 1 June 2004.
No further call for workshop proposals will be made.
The BIRD Programme confirmed support for the following workshops in 2004:
Workshop on Identifying migration and wintering areas of breeding populations of migrant passerines, Tokaj, HU, 14-17 October 2004. For further details, contact
- TiborSzépE-Mail
- Hungarian Ornithological Society (MME)BudapestHungary
Working group meeting on Genetic aspects of migration, Germany, dates to be confirmed. For further information, contact
- ArieVan NoordwijkE-Mail
- KNAWNetherlands Institute of EcologyHeterenNetherlands
A first Programme workshop, on "Optimal Bird Migration - from theory to tests", was held in Wilhelmshaven (D) on 30 November - 3 December 2000.
The BIRD Programme has also supported a PhD student course in Ecology of animal migration, held at Lund University (SE) on 4-15 November 2001, as well as a workshop on Satellite tracking of long distance animal movements: studies of navigation and migration performance, held in Lund (SE) in February 2002 and a workshop on Migratory birds and parasites, held in Styria (AT) on 6-9 November 2002 Go to Website.
Reports on BIRD-supported workshops and visits
Reports on BIRD-supported workshops and visits can be found on the BIRD Website
