Backman, J., Pettersson, J. & Sandberg, R. 1998. The influence of fat stores on magnetic orientation in day-migrating Chaffinch, Fringilla coelebs. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 359.

Earlier experimental studies have demonstrated the ability of day-migrating birds to perform migration under overcast skies, thereby indicating use of cues other than solar. The orientation behaviour of the Chaffinch, a diurnal migrant, was investigated in orientation cage experiments during the autumn migration period. The aim of our experiments was to examine the relationship between different orientation cues and the influence of body condition on directional choices. We obtained the following results: (1) Chaffinches displayed a bimodal distribution of headings along a SW-NE axis when tested in the local geomagnetic field (controls). (2) When the geomagnetic field was experimentally deflected 90° counterclockwise, the Chaffinches responded by changing their preferred axial orientation to SE-NW; and (3) The predictive power of stored fat reserves became evident when both the control and experimental samples were subdivided into fat and lean individuals. The majority of fat controls oriented towards a seasonally appropriate SW direction, whereas lean controls chose mean directions towards the NE. The experiment followed the same pattern, but with the expected deflection, i.e. fat birds selected SE headings and lean individuals chose a northwest mean direction.

Key words: magnetism, orientation, diurnal, energetics, body condition

 

Combreau, O., Launay, F. & Al Bowardi, M. 1998. Inter-individual variations in the annual migration of Houbara Bustard tracked by satellite. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 360.

The annual migration of five Houbara Bustards Chlamydotis undulata captured in Abu Dhabi Emirate between 24 February and 02 March 1997 was studied by radio-tracking via satellite. The Houbaras were captured with a disarmed falcon and harnessed with a 28 g Microwave Telemetry Inc solar-powered PTT. They left the UAE between the 18 March and the 2 April 1997. They invariably flew eastwards along the coast towards the strait of Hormuz before crossing to Iran. The return migration lasted from 13 to 73 days depending on individuals. The birds covered between 1900 to 6000 km travelling at a rate ranging from 34 to 181 km/day. One Houbara spent the breeding season in northern Afghanistan, one in Uzbekistan (south of the Aral sea), two in Kazakhstan (including one in the north of the Aral sea and one in the Kyzylkum desert), and one in China (north of Koko Nor lake). They stayed between 115 to 193 days on their breeding grounds. The outward migrations started between the 9 September and the 7 November and lasted between 13 to 58 days. The Houbaras covered between 1170 and 5800 km travelling at a rate ranging from 84 to 135 km/day before they reached their wintering grounds. Three wintered in Iran, one on the Iranian-Afghanistan border. The Houbara that had wintered in China was the only one to return to the U.A.E.

Key words: radio-tracking, ARGOS, central Asia

 

Gannes, L. Z. 1998. Comparative fuel use of spring passerine migrants. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 361.

Laboratory and theoretical evidence suggest that body composition affects fuel use and protein conservation during migrational flight. However, field reports from autumnal migrants are equivocal. I tested the hypothesis that body composition affects fuel use strategy on new arrival passerines caught during spring migration in the Negev Desert, Israel. Preliminary analyses of blood metabolites show in-flight fuel use differences between Common Redstarts Phoenicurus phoenicurus and Blackcaps Sylvia atricapilla. In flight, blackcaps rely more on lipid and less on protein fuel sources than do redstarts. The results suggest that blackcaps are more "fuel-efficient" than redstarts. However, contrary to my predictions, preliminary results indicate that the interspecific fuel-use differences are independent of body composition. The results suggest that migrating birds have species specific "fuel efficiencies" similar to that found in fasting birds. As a result, a fuel-efficient species could migrate farther relying solely on its body reserves than a less fuel-efficient migrant. The interspecific differences may be a function of phylogeny, migrational distance and/or migrational strategy. Funded by NSF and Sigma Xi grants.

Key words: Sylvia atricapilla, passerine, efficiency, Phoenicurus phoenicurus

 

Griffioen, P., Clarke, M., Ambrose, S. 1998. Silvereye migration patterns revealed by computer analysis of band recovery and national bird count data. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 361.

The Australian Bird Count (ABC) data are the result of a national survey of land birds that spanned six years (1989 - 1995). A primary aim of the ABC was to provide information on the location and timing of bird movements. We investigated the utility of the ABC data to achieve this aim by examining the data of the Silvereye, Zosterops lateralis. The location and timing of known movements by Silvereyes, as determined from recoveries of bird bands, were used to generate predictions of Silvereye density changes in the ABC data. Bird band recovery vector maps were generated for each month, from which both spatial and temporal data could be extracted. The ABC data set reflected the changes in population densities due to movement patterns predicted from the band recovery data, in three out of five cases. The ABC data were then subjected to geographical smoothing and interpolation to produce maps. From the maps, nine regions were identified as apparent sources and destinations of Silvereyes. Significant changes in the abundance of Silvereyes across months were detected in eight of those regions. The timing of the significant changes in Silvereye abundance in some of the regions suggest complex movement patterns for this species on the Australian mainland, as well as the previously known migration to and from Tasmania.

Key words: migration, Australian Bird Count, mapping, band recoveries

 

The Department of Forest Conservation, South-west Forestry College, Xiaoba, Bailong Temple, Kunming 650224, Yunnan, the People's Republic of China, e-mail lianxian@public.km.yn.cn

Kaatz, Ch. & Kaatz, M. 1998. The company of passage by plane and minibus of storks Ciconia ciconia provided with transmitters at their East European passage. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 362.

The application of satellite telemetry to White Storks took place at the beginning of the 1990’s through the Max-Planck-Institute for Behavioural Physiology, Ornithological Station Radolfzell and the Federal Office for Nature Conservancy Bonn. The inclusion of the stork farm Loburg (Saxony–Anhalt) followed a little later. This provided a good basis for implementation of investigations of storks that carry transmitters to their places of rest and landing along migration routes. This could be achieved after tests in 1993 and 1994 and was perfected in the years 1995 until 1997. It is assumed that storks with transmitters indicate the passages of other migrating storks and high numbers of storks there emphasize this. The poster conveys the often adventurous search and discovery of White Storks with satellite transmitters in several countries between Germany and Poland and Turkey and it highlights the possibilities of ecological investigations of these resting-places. The relevance of conservation of these areas is emphasized. The completed ecological investigations at the places of rest and landing constitute the basis for new conceptions of protection along the migration passages.

Key words: satellite telemetry, transmitters, resting places, migration passages, White Storks.

 

McCann, K.I. & Shaw, K. 1998. The analysis of Blue Crane Anthropoides Paradiseus movement patterns in South Africa using satellite telemetry. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 363.

The Blue Crane Anthropoides paradiseus is South Africa’s national bird and is virtually endemic to South Africa. It is listed as "critically endangered" in the latest IUCN / SSC Crane Specialist Group publication, "The Crane: Status Survey and Conservation Action Plan". There is a lack of information about the daily and long-distance movement patterns of Blue Cranes. This poses a substantial problem to Blue Crane conservation, as events while on their wintering grounds have an influence on survival and future reproductive success. The use of satellite tracking technology is an urgent requirement in further elucidating the movements, wintering areas and in the formulation of long-term conservation plans for this threatened species. Ten Blue Cranes have been fitted with satellite transmitters. Argos, an environmental satellite company in France, is currently being used to download, process and supply the geographical locations of the Blue Crane individuals. The birds move off the natal areas with the parents, some as early as 5 months after hatching. They remain in the wintering areas, returning to their respective natal areas in time for the breeding season. The now one year old birds then congregate to form small flocks, which either move away from or remain in the vicinity of the natal area.

Key words: Blue Crane, satellite telemetry, local migrant, conservation management

 

Muheim, R. 1998. Phototactic responses in orientation experiments with Robins Erithacus rubecula caught at Col de Bretolet, Switzerland. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 364.

Orientation experiments in funnels are usually carried out with birds that are handraised or caught during resting periods at stop-over sites. At a ringing station in the Swiss Alps, run by the Swiss Ornithological Institute, topographical circumstances allow birds to be caught during active migratory flight. Therefore, birds can be tested immediately after catching in their natural migration environment, and are therefore expected to be in full migratory disposition. Orientation experiments with Robins, however, showed that birds tested during the night were influenced by the moon and showed phototactic behaviour whereas birds tested on moonless nights were disoriented. Robins that were kept for one day in captivity and then tested around sunset mainly chose directions close to the sunset position in the west-southwest. This seems to be rather a phototactic reaction towards the setting sun than true orientation into the seasonally expected migratory direction in the south-southwest. I conclude that birds caught at Col de Bretolet are not able to orientate properly even when tested at a time birds usually initiate their migratory flight. Stress or other unknown factors might disturb the bird's orientational abilities at Col de Bretolet.

Key words: migration, orientation, phototaxis, Erithacus rubecula, moon

 

Osborne, T.O. & Osborne, L.Y. 1998. Kori Bustard movements in Etosha National Park, Namibia. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 364.

Kori bustards Ardeotis kori are reported to have conspicuous eastern and lowland movements during the austral winter in southern Africa. These movements were from old records and none were based on marked birds. We patagial marked 48 bustards and affixed radiotags to 19 birds. The marked birds were radio-tracked for 16 months. Adult males embarked on a walkabout after the breeding season with some birds ranging up to 90 km from the tagging site. Adult females with chicks usually stayed within smaller home ranges. Predation of chicks caused sudden movements outside the normal female range. One female with a chick moved 55 km. We found no evidence of conspicuous or co-ordinated movements based on the onset of the austral winter.

Key words: territory, home range, radio-tracking, Ardeotis kori, Africa

 

Peske, L., Miroslav, B. & Pojer, F. 1998. Satellite and conventional radiotracking of the Black Stork migration: different routes but same individual wintergrounds. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 365.

Since 1995, the African odyssey project has aimed to collect the migration data of Black Storks Ciconia nigra. An important part of the project is the satellite monitoring and also conventional radiotracking of tagged birds at their homeranges and during overland expeditions to their winter-grounds in Africa. During 1995, 1996 and 1997 we caught and tagged 3, 3 and 4 adult birds respectively, some of them repeatedly. On a large scale we can now describe an overall migration pattern. Birds from the Czech Republic use both main migratory routes via Gibraltar and via Israel, and they winter at small water bodies in the sub-Sahara savanna. We collected data about the migration timing, speed, migration stop-overs, important feeding places and also bottle necks. We studied the behaviour of the stork and the natural environment of their winter-grounds in the Senegal, Chad and also Ethiopia. The design of the project enabled us to recover birds in the following year at their breeding sites and recharge their transmitters. Thus we can compare individual fidelity to the breeding places, migration routes, stop-overs and winter quarters. In two instances in subsequent years the routes deviated significantly, but birds reached exactly the same winter-grounds. The total distance to the main wintering places, measured as the length between migration roosts (joining "accepted" satellite locations) via Gibraltar was 4930 km and 5211 km, whereas via Israel it was 6550, 6770, 5419 and 6188 km.

Key words: site fidelity, Ciconia nigra, speed of migration, satellite monitoring, migration bottlenecks

 

Scheiffarth, G. & Bairlein, F. 1998. Spring migration strategies of two populations of Bar-tailed Godwits Limosa lapponica in the Wadden Sea. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 365.

Two populations of Bar-tailed Godwits use the European Wadden Sea as a stop-over site on migration between wintering and breeding grounds. The Afro-Siberian population conducts a 4000 km non-stop flight to the breeding grounds and stays in the Wadden Sea for one month while birds gain 5.6 g.d^-1 in weight. The European population stays for 2-3 months in the Wadden Sea and gains 1.5 g.d^-1 in weight for a 2000 km flight to the breeding area. Intake rates in April/May did not differ between the two populations (1.5 kJ.min^-1 for the Siberian and 1.8 kJ.min^-1 for the European migrants) but total energy intake was higher for the Siberian migrants, since they spend 50% of the day foraging vs. 30% in the European birds. The Siberian population had a lower basal metabolic rate (6.35 m.W.g^-1 vs. 8.3 m.W.g^-1), occurred in the Wadden Sea later in the season, when thermoregulatory costs were lower, and started moulting into the breeding plumage in the wintering quarters. Thus, the higher overall energy demand of the Afro-Siberian birds seem to be fulfilled by a combination of physiological adaptations, a tight time schedule, and a high working level.

Key words: spring migration, energetics, basal metabolic rate, Limosa lapponica

Tyler S.J. & Tyler L. 1998. A study of warblers in reedswamp in south east Botswana. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 366.

Construction of reservoirs and sewage lagoons has had a dramatic impact on the occurrence of Palearctic and African Acrocephalus warblers in south east Botswana. Seasonal changes in numbers and ecology of species using Typha swamp at Phakalane sewage lagoons near Gaborone were studied between September 1996 and August 1997 by regular mistnetting, ringing and direct observations. Over 500 Acrocephalus warblers were caught on 28 visits. The first Palearctic migrants, A. schoenobaenus and A.scirpaceus, were caught in early November. A. arundinaceus arrived in late December and A.palustris not until March. An influx of new Palearctic migrants arrived in late January. Many birds remained at the site until March or April. During March a further passage occurred. The African migrant A. baeticatus was common from November to March with a few present throughout June and July. During the austral summer A. baeticatus foraged extensively outside the swamp, in nearby Acacia trees, whereas A.gracilirostris and Bradypterus baboecala foraged within the swamp, the former using even narrow fringes of reedmace. Highlights of the study included the first record of A. griseldis in Botswana, and 53 European Reed Warblers, few having been recorded previously in Botswana.

Key words: warblers, Acrocephalus, Bradypterus, palaearctic, reedswamp, Typha

 

Widmer M. 1998. Differences and their causes in the timing of spring migration between lowland and mountain populations of the Garden Warbler Sylvia borin. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 367.

One of the most remarkable differences between lowland and a mountain population of the Garden Warbler Sylvia borin concerns the spring arrival. The birds of the mountain population arrive three weeks later on the breeding grounds than their conspecifics in the lowlands. This remarkable difference could be based on exogenous factors or Garden Warbler populations living under different climatic conditions could have distinct endogenously controlled migration programs. To test these hypotheses I collected a total of 95 nestlings from the Upper Rhine Valley (200 m.a.s.l) and the Central Swiss Alps (1500 m.a.s.l) they were hand raised and kept under standardized conditions in laboratory for almost one year. Mountain birds begun with spring migratory activity (under two different photoperiodic treatments) significantly later than lowland birds. This and other results support the hypothesis that mountain and lowland birds differ in their endogenously controlled migration programs. From heritability estimates obtained from a full-sib analysis it can be concluded that this trait has an additive genetic variance and could be modified by selection.

Key words: spring migration, circannual rhythms, altitude, genetic differentiation, Sylvia borin