Navigating danger: How environmental cues and individual traits shape breeding dispersal in the endangered common eider

Breeding dispersal, or movement between successive breeding sites, is insufficiently understood. A ‘win-stay, lose-switch’ (WSLS) strategy may facilitate predator avoidance, but this strategy may be modulated by individual traits. We studied the drivers of breeding dispersal within and between breeding islands in female common eiders (Somateria mollissima), a ground-nesting site-fidelic sea duck, in the northern Baltic Sea. Rapidly increasing predation led us to expect increased dispersal over time. Using data spanning 21 years (2003-2023), we investigated which individual traits (nest success, age, body condition, boldness, relative head size) and environmental factors (predation risk, breeding density) influenced breeding dispersal. Within-island breeding dispersal distances showed moderate repeatability (r = 0.45), indicating individually consistent dispersal distances across years, but dropped to 0.20 after accounting for significant fixed effects, highlighting the roles of environm..., , # Data from: Navigating danger: How environmental cues and individual traits shape breeding dispersal in the endangered common eider

**Article title:** Navigating danger: how environmental cues and individual traits shape breeding dispersal in the endangered common eider

**Journal:** Behavioral Ecology

**Authors:** Ida Hermansson; Mikael von Numers; Kim Jaatinen; Jens Skog; Markus Öst

**Corresponding author:** Ida Hermansson ([[e-mail]](mailto:[e-mail]))

#### Dataset Overview

**File**: dataset_breeding_dispersal.csv

Dataset underpinning analyses of breeding dispersal in female common eiders across 21 years in the northern Baltic Sea. Variables include individual traits, island attributes and predation risk indices. Used to test win-stay, lose-switch (WSLS) responses and influences of environmental cues on within- and between-island dispersal.
The dataset was used for four analyses: 1) factors explaining breeding dispersal distances within islands, 2) fac...,