Comparative foraging behaviour of three species of shrike in southern Africa

Abstract

Utilisation of food resources in migrant and resident birds living sympatrically often leads to differences in feeding strategy. For sit-and-wait hunters such as shrikes, it is connected with competition for food and hunting places. In this study, foraging behaviour of three shrike species was studied in savanna-like habitat in southern Africa. The fieldwork was carried out in December 2017 during wintering season of Lesser Grey Shrike Lanius minor and Red-backed Shrike Lanius collurio and breeding season of Common Fiscal Lanius collaris. Details of the bird’s behaviour were recorded during 30 min observations of each bird. A general linear mixed model with logit link function and binomial error variance was used to compare the species’ behaviour. Although the type of perch-site and perching time did not differ between species, Red-backed Shrike used places situated significantly lower than other shrikes. This species also more often used bushes and attacked from lower perch-sites than Lesser Grey Shrike. This may possibly be due to interspecific competition and antipredator behaviour of Red-backed Shrike. No differences in foraging behaviour between Common Fiscal and Lesser Grey Shrike were observed. All three species utilised the same category of prey. Hunting success (the ratio of successful to all attacks) was low and similar in all three species (47%–57%). The lack of statistically significant differences in behaviour, hunting success and size of prey items among shrike species may be a consequence of the relatively short observation time and small sample sizes.

Keywords: Common Fiscal, hunting success, Lesser Grey Shrike, perching, Red backed Shrike, savanna-like habitat