Aline Bertin

Adult influence on song development was rarely investigated in complex social settings. We investigated the influence of the young/adult ratio on song learning in European starlings. Starling songs are composed of two categories: whistles and warbling. Warbling includes three parts: complex variable motifs, click motifs, and high frequency motifs. Song learning by young birds raised in group (G birds), in group with adults (GT birds) or in pair with one adult (IT birds) were compared. Song tutor choice, song sharing, and song quality varied with social context. The mere presence of adults in a group was not sufficient for young to develop all adult song features. Only IT birds chose adults as tutors. Social contact with only one adult enhanced acquisition of whistles, click motifs, individuality, and reduced the number of high frequency motifs (adult song features). This study suggests that the adult influence is proportional to young/adult ratio. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 362–374, 2007.

Temporal characteristics of migratory behavior in birds are usually studied at the species and population levels, and rarely at the individual level. Variations among species and populations of the seasonal onset of migratory behavior have been widely investigated, but very little is known about its daily organization or whether birds are conservative in their behavior. The determination of intra‐ and inter‐individual variability is important for the study of genetic variations and can reveal the existence of different adaptation capacities within populations. This laboratory study analyzed intra‐ and inter‐individual variability of daily initiation and time course of nocturnal restlessness in partial‐migrant European quail (Coturnix coturnix coturnix). Thirty‐five quail were selected randomly from a captive stock, and their spring activity was recorded under natural daylenghs. Eighteen of the thirty‐five quail presented behavioral profiles of migrant birds. Migrant birds initiated their nocturnal activity punctually, and the time courses of the nocturnal activity of 88% of them revealed intra‐individual stability over six consecutive nights. All birds initiated their nocturnal activity after sunset and civil twilight, and they were more active at the beginning than the middle or end of the night, suggesting that their drive to migrate could be synchronized with particular skylight conditions. For the first time, stable individual profiles in the daily time course of migratory restlessness are shown. These results support previous findings concerning biological rhythms of quail and raise questions concerning the timing of migratory behavior.