Foraging guild structure of seabirds

Abstract

An ecological guild is a group of species that exploit the same resources, or that exploit the same or different resources in a related way. We built The Foraging Guilds of Seabirds database (FGSdb) by compiling a global database of 311 seabird species (from a total of 346 known) and assigning to each of them their diet types and foraging strategy. Across all seabirds, there were found 22 diets and 30 strategies. The number of diet categories for a species varied between 1 and 11, and the number of strategies varied from 1 to 9, with averages of 2.71 and 3.65, being the ratio diet/strategies of 0.74 ([~]3/4), meaning that on average with four strategies they can exploit up to 3 diet items. Beyond this description, we show that the Gusein-Zade model fits well both the frequency rank and number of species per guild distributions. Our database and analyses provide a useful resource database for future studies and demonstrate simple rules behind guild structure.