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