Carotenoid skin ornaments as flexible indicators of male foraging behavior in a marine predator: Variation among Mexican colonies of Brown Booby (Sula leucogaster)

Carotenoid-dependent ornaments can reflect animals’ diet and foraging behaviors. However, this association should be spatially flexible and variable among populations to account for geographic variation in optimal foraging behaviors. We tested this hypothesis using populations of a marine predator (the brown booby, Sula leucogaster) that forage across a gradient in ocean depth in and near the Gulf of California. Specifically, we quantified green chroma for two skin traits (foot and gular color) and their relationship to foraging location and diet of males, as measured via GPS tracking and stable carbon isotope analysis of blood plasma. Our three focal colonies varied in which foraging attributes were linked to carotenoid-rich ornaments. For gular skin, our data showed a shift from a benthic prey-green skin association in the shallow waters in the north to a pelagic prey-green skin association in the deepest waters to the south. Mean foraging trip duration and distance of the foraging si..., We studied three colonies of brown booby from Islas Marietas (n=16; July to August 2016), Isla San Pedro Mártir (n=44; January to February 2018), and Isla San Jorge (n=17; December 2016 - January 2017) Mexico, during the incubation and chick-rearing phases of breeding. To measure foraging behavior and habitat use at sea, we tracked brown boobies from each colony for 6–10 days using miniature GPS tags. We used tracking data to 1) quantify foraging trip duration and total distance traveled on unique foraging trips (as indicators of foraging behavior), and 2) measure ocean depth and distance to coast at foraging locations (two physical variables describing the environment). The mean values of tracking metrics per individual were used for the analyses.
To evaluate skin color, we measured the reflectance of two brown booby skin traits  (gular and feet) using a handheld spectrophotometer (MINOLTA CM 2600d, Osaka, Japan), which collected reflectance spectra at 10 nm intervals from 360 to 740 n..., , # Carotenoid skin ornaments as flexible indicators of male foraging behavior in a marine predator: Variation among Mexican colonies of Brown Booby (*Sula leucogaster*)

[https://doi.org/10.5061/dryad.905qfttt7](https://doi.org/10.5061/dryad.905qfttt7)

## Description of the data and file structure

| Variable | Definition | | | |
| :------------ | :--------------------------------------------- | - | - | - |
| id | identity of each bird (colonyyearspbandnumber) | | | |
| id-bdd | id within the bdd for this project | | | |
| colony | 1=San Jorge; 2=San Pedro; 3=Marietas | | | |
| stage | 1=incubation; 2=chick rearing | | | |
| duration | average trip duration (hrs) | | | |
| depth | average depth during searching trips (m) | | | |
| distcost | average distance from the cost (km) | ...