Intrinsic and extrinsic factors modulating vigilance and foraging in two gregarious foragers

Individuals need to trade-off vigilance and foraging, but species differ in how they manage this. We explored the effects of both intrinsic and extrinsic factors on individual vigilance/foraging patterns in two migratory, gregarious bird species markedly differing in body size and foraging strategies, the Greylag Goose Anser anser and the Common Crane Grus grus, during the non-breeding period.
We show that vigilance in individuals of both species decreased with increasing group size and distance from the edge of the group. However, the two species varied how they allocated the freed up time. While cranes allocated the resulting time to foraging, the same did not occur in geese. In addition, we investigated changes in individual position in the group (i.e., peripheral vs. central or vice versa) and how they elicited a prompt behavioral change (i.e., vigilance vs. foraging or other activity). We also explored whether the time elapsed since arrival in non-breeding grounds and proximity to ..., Our study was conducted in the Northern sector of the Maremma Regional Park (42°39′N, 11°05′E), a protected area in Tuscany (Central Italy). Behavioral observations were conducted between the end of October and the end of January, during two consecutive wintering seasons (2019/20 and 2020/21). Observations were carried out from vantage points 5-7 m above the ground, whilst the observer maintained a 200-500 m distance from the flocks in order to minimize potential alteration of birds’ behavior. Further information on behavioral observations and data collection can be found in section 2.2 of the paper. All the analyses can be replicated by following the statistical procedure and by using the software described in the Methods section of the paper., , # Data from: Intrinsic and extrinsic factors modulating vigilance and foraging in two gregarious foragers

## Description of the data and file structure

Two datasets are provided to reproduce the analyses of the paper \"Intrinsic and extrinsic factors modulating vigilance and foraging in two gregarious foragers\". Each file has its legend including variables' names and descriptions. The file 'Dataset_drivers.xlsx' can be used to reproduce the analyses on the species-specific drivers of vigilance and foraging behavior in geese and cranes (section 3.1 of the paper), as well as the interspecific analysis (section 3.2 of the paper). The file 'Dataset_repositioning_events.xlsx' can be used to reproduce the analyses on the species-specific behavioral changes in relation to spatial position in geese and cranes (section 3.3 of the paper).

All the analyses can be replicated by following the statistical procedure and by using the software described in the Methods section of the paper.

## Shari...