Pinxten R., van Elsacker L. & van Verheyen R.F. (1987) Duration and temporal pattern of mate guarding in the Starling. ARDEA 75 (2): 263-269

Data were collected to test the idea that male Starlings guard their mates during their fertile period from mating attempts by other males. Detailed observations on the pattern and duration of mate-escorting behaviour of six male Starlings in the breeding area, indicated that guarding started about 4 days prior to laying and strongly declined with the laying of the second or third of six eggs. Guarding intensity was highest during the fourth and third day before laying. This pattern is consistent with the idea that to maximize the chances of successful fertilisation, insemination should occur at least 48 h before the first ovulation. Our results suggest that, compared to monogamous species, males of polygynous species like the Starling, terminate guarding one or two days earlier, in order to try to attract a second female. However, one has to take into account that guarding of females might serve other functions (e.g. protecting females from predation and induction of hormonal changes in both pair partners), because we never witnessed extra-marital matings in our Starling population.