Feather characteristics for eye protection in an insectivorous passerine: the Iberian grey shrike Lanius meridionalis, in southern France

In the French Mediterranean plain, the northern extreme of its native range, the Iberian grey shrike, Lanius meridionalis, predominantly feeds on arthropods. Its type of loral plumage plays a key role in protecting its eyes while transporting large prey. The aims is to understand the role played by feathers in protecting the animal from various types of defensive prey. We combine an inspection of large insect prey types found on larders with a review of bird specimens found in museum collections to examine the morphometric characteristics of rictal feathers and culmen. In addition, precision photographs are used to observe the posture of the plumage in natura. We could identify four categories of protective feathers: clustered bristles, semi-bristles, semi-plumes distributed in the loral area, and semi-plumes above the eyes. Our results suggest that the Iberian grey shrike has a complex structure of loral feathers, specific to its foraging activity and prey types. In France, local species have longer beaks than their Spanish counterparts which suggests a more insect-based diet.