Joseph, L., Lessa, E.P. & Christidis, L. 1998. Phylogeny and biogeography in the evolution of migration. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 196.

A long-standing issue in the evolution of migration has been how to determine whether any given migration between breeding and non-breeding grounds, which may be on different continents, evolved through origins in the breeding grounds with successive shifts of the non-breeding distribution or vice versa. Notwithstanding that migration can evolve rapidly, we approach this as a problem in historical biogeography. We map breeding and non-breeding distributions as characters onto a phylogeny of the Charadrius shorebird complex derived from mitochondrial DNA sequence data and examine case-by-case changes in breeding and non-breeding distributions. Shifts of breeding distributions in the evolution of migration in C. alexandrinus and C. veredus are apparent. Also apparent is a Southern Hemisphere origin for the group (specifically, South America) and this implies other shifts in breeding distributions in the evolution of C. semipalmatus and C. vociferus. These results add to an emerging consensus from the evolutionary ecology of migrant birds that shifts of breeding distributions are commonly, though not necessarily exclusively, involved in the evolution of migration.

Key words: migration, phylogeny, biogeography, Charadrius

Pulido, F. & Berthold, P. 1998. Evolutionary quantitative genetics of migratory behaviour in the Blackcap Sylvia atricapilla. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 196.

We studied the quantitative genetics of incidence, amount, onset, and termination of autumn migratory restlessness in the Blackcap with the aim of predicting potential patterns and rates of evolutionary change in migratory behaviour. Drawing on data of over 1300 individuals from two populations, we assessed genetic variances and covariances using full-sib correlations, parent-offspring regressions, and responses to artificial selection. We found high phenotypic variation and significant heritabilities for incidence, onset and amount of migratory activity, demonstrating high potential for evolution of these traits. Termination of autumn migration, however, has a low heritability, suggesting that variation in this trait can be strongly influenced by environmental factors. High genetic correlations among all traits studied indicate that migratory traits are expressed as a syndrome, i.e. a suite of correlated traits. Selection acting on any of these traits thus will induce changes in all other traits. If, for instance, the survival of sedentary individuals increases due to milder winters on the breeding grounds, the frequency of non-migrants will rise in the population as a direct response to selection. Moreover, we expect that migratory individuals of that population will gradually delay their departure from the breeding grounds and shorten their migration distance as a correlated selection response.

Key words: selection, evolution trajectory, migration syndrome, genetic constraint, global warming

Schaub, M. 1998. How long do birds stop at a resting place during migration? In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 197.

For the understanding of migration strategies it is crucial to know the duration of stopover at resting places. With capture-recapture analysis, it is possible to estimate stopover duration and to test for effects of additional variables. The software program RELEASE was used to test the fit of the data to the Cormack-Jolly-Seber model and to detect possible heterogeneities among individuals (e.g. transients, trap response). Program SURGE was used to find the best model and to calculate survival rates. With the ordinary capture histories, stopover duration after first capture can be calculated. Stopover duration before first capture was calculated with a similar survival analysis using the reversed capture histories. Both these stopover durations provide an estimate of total stopover duration. Preliminary results of first year Reed Warblers Acrocephalus scirpacaeus from the Bolle di Magadino (Switzerland) in autumn 1996 showed that total stopover duration was constant over season and that light and heavy birds stayed for similar times (mean: 7.5 days, 95% confidence interval 5.8-9.8 d). No heterogeneity could be detected. The contribution of time before first capture was 18% of total stopover duration.

Key words: stopover duration, capture-recapture, Acrocephalus scirpaceus, population, condition

Salewski, V., van Stünzner-Karbe, D., Bairlein, F. & Leisler, B. 1998. Winter site fidelity and territoriality of the Pied Flycatcher in its West-African winter quarters. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 197.

During the winters 1994-95 to 1996-97 including a preliminary study in spring 1994, the ecology of palaearctic migrants was studied in Comoé National Park, Ivory Coast. The study focused mainly on the Pied Flycatcher Ficedula hypoleuca. Birds were mistnetted in selected plots in different habitat types and marked individually with colour rings in all field seasons. Additionally twelve birds were equipped with radio transmitters in the season 1995-96. The study revealed that Pied Flycatchers show a high winter site fidelity and returning rates in successive winters with one bird reappearing to the same plot in all four winters. However, the returning rates are dependent on habitat type, being lower in plots which were supposed to be sub-optimal. These plots seem to be occupied by birds without a territory which are likely to change habitat if possible. Territories were occupied by both sexes but the sex ratio was different between the habitat types. This study was supported by the Deutsche Forschungsgemeinschaft and the VolkswagenAG.

Key words: Ficedula hypoleuca, Comoé National Park, Ivory Coast, habitat quality, radio tracking

Mabey, S.E. & Woodrey, M.S. 1998. An experimental test of intersexual competition during migration. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 198.

Sex-based differential migration has long been understood in terms of male-male competition for breeding territories and competition-mediated male-female segregation during the non-breeding season. However, few studies have considered the behavioural basis and ecological consequences of differential migration during stopover. We hypothesised that if intersexual competition helps mediate differential migration, dominance will be rewarded in energy currency; and the earlier migrating sex (males) will be dominant to the later sex (females). To evaluate these hypotheses, we conducted an experimental test of intersexual competition during northward migration using Pied Flycatchers Ficedula hypoleuca in a field aviary setting. Flycatchers were trapped at Ottenby Fägelstation, Sweden and 10 male-female matches were chosen based on condition. In all trials there was a significant difference in behaviour of the two birds with one bird moving less, supplanting more, and consuming more mealworms than the other. Additionally, significantly more "winners" were males (7) than females (3). Our results suggest that intersexual competition is an important factor facing migrants and that, although individual females are capable of out-competing males, females may suffer reduced energy gain relative to males present at the same stopover site.

Key words: dominance, stopover, differential migration, Ficedula hypoleuca, Pied Flycatcher

Bauchinger, U. & Biebach, H. 1998. Protein composition in the flight muscle: An adaptation to sustained flight in long-distance migratory Garden Warbler Sylvia borin. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 198.

Key words: Sylvia borin, flight muscle, protein composition, sustained flight

Ramenofsky, M. 1998. A re-evaluation of the role of corticosterone and migration. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 198.

The adrenal glucocorticoid, corticosterone, has long been considered to play a major regulatory role during periods of high energy demand such as migration. Migration, however, takes many forms. Some birds move only short distances over relatively benign habitats between breeding and wintering localities. Whereas others may fly thousands of kilometres over locations that prohibit landing for feeding and rest. Season, age, and sex likewise contribute variability as selective pressures on individuals to rapidly complete the journey diverge with stage. Confusion has arisen in the literature where diverse species have been investigated. Elevations of plasma corticosterone have been described frequently as a response to the stress of migration. Or in other cases, no change in circulating levels of corticosterone following capture and handling have been described as a lack of a response to capture stress. Corticosterone has diverse effects that range from metabolism to behaviour thus adding to the confusion of what rises and falls of this hormone actually mean. Application of life history stages of a particular species as well as a systematic consideration of the energetic demands of flight may provide heuristic value to correctly identifying: (1) the role of corticosterone during migration and (2) helping to further understanding of this extraordinary phenomenon.

Key words: hormone, physiology, corticosterone, life history stages, energy balance

Marchetti, C. & Baldaccini, N.E. 1998. The role of the moon in passerine migratory orientation: Comparison of spring and autumn experiments. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 199.

The effect of the presence of the moon on orientation tested in Emlen funnels differed between passerine migrant species. We tested two species (Pied Flycatcher Ficedula hypoleuca and Willow Warbler Phylloscopus trochilus) in Emlen funnels in autumn and spring, under clear skies, using mirrors deflecting the moon by 180°. If the orientation towards the mirror is the same in spring and autumn, it is phototaxis, if it is different, it may be orientation; birds could also disregard moon and mirror, or be disoriented. The Pied Flycatcher was disoriented in spring, while it disregarded the moon and was not different from the controls in autumn. The moon is thus not used as reference by the Pied Flycatcher. In spring the Willow Warbler showed a tendency to head in the opposite direction from the moon, as expected, with high individual variation. More autumn data on the Willow Warbler, to be collected in 1997, will tell us whether the spring data are to be interpreted as phototaxis or whether the moon is used as an orientational cue at least by the Willow Warbler.

Key words: migration, moon, passerines, Ficedula hypoleuca, Phylloscopus trochilus