title: The predictability and patterns of vigilant behaviour.
abstract: While foraging, many animals alternate between feeding and scanning. Spectral analysis of continuous series of scan durations S and inter-scan intervals I for American Goldfinches Carduelis tristis, feeding either on small or large seeds, and choughs Pyrrhocorax pyrrhocorax showed that there were nonrandom fluctuations in the magnitude of S and I is all the examined series. Both the I and S showed cyclical oscillations between short and long events. Within individuals the sequential and temporal patterns in the I and S series were similar. However, the temporal patterns were more affected by variations in food-handling time than were the sequential ones. The predictability of the I and S series and the similarity, within individuals, of their sequential and temporal patterns seem general processes resistant to variations in behavioural constraints, and the temporal patterns in the I and S series fit to the method of handling food.
authors.affiliation: Centre de Recherche en Biologie du Comportement, CNRS URA 664 & UPS, 118 route de Narbonne, 31062 Toulouse Cédex France.
authors.forename: J P
authors.initials: JP
authors.lastname: Desportes
authors.affiliation: Department of Zoology, The University, Glasgow G12 8QQ UK.
authors.forename: N B
authors.initials: NB
authors.lastname: Metcalfe
authors.affiliation: Department of Biological Sciences, University of Wisconsin, Milwaukee, WI 53201 USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Popp
authors.affiliation: Edward Grey Institute, Department of Zoology, Oxford University, South Park Road, Oxford OX 1 3PS UK.
authors.forename: R M
authors.initials: RM
authors.lastname: Meyer
authors.affiliation: Centre de Recherche en Biologie du Comportement, CNRS URA 664 & UPS, 118 route de Narbonne, 31062 Toulouse Cédex France.
authors.forename: A
authors.initials: A
authors.lastname: Gallo
authors.affiliation: Edward Grey Institute, Department of Zoology, Oxford University, South Park Road, Oxford OX 1 3PS UK.
authors.forename: F
authors.initials: F
authors.lastname: Cézilly