Data from: Not all who wander are lost: Prospecting and settlement of male floaters in the spotless starling
Data files
Apr 08, 2025 version files 247.93 KB
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Prospecting_and_settlement.csv
179.02 KB
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Prospecting_at_breeding_stages.csv
63.52 KB
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README.md
5.38 KB
Abstract
Floaters are non-breeding individuals that lack a territory or a breeding site. In many species, they can be seen visiting the territories of conspecifics before obtaining their own breeding site. Prospecting behavior is hypothesized to benefit floaters through information acquisition, enhanced site familiarity and dominance over other floaters. Here, we used detections of PIT-tagged male floaters in a population of spotless starlings (Sturnus unicolor). We investigated how floater activity varied across breeding stages and how their visits influenced subsequent nest site selection. We also tested whether distance, reproductive success, and phenotype and fate of the former owner influenced final settlement. We found that floater activity increased during the nestling-rearing period as nestling age increased. Floaters were more likely to breed near the area where they had been detected the previous year, suggesting that prospecting allows males to secure a foothold in their future settlement area. Although prospecting was higher in nests with a higher number of nestlings, neither breeding success, phenotype, nor provisioning rate of the last owner were related to nest choice, suggesting that public information is not used by males to decide where to settle. However, we found that floaters were more likely to breed in nest boxes where the previous owner had disappeared from the colony, suggesting that visits by male floaters in this species allow them to detect new vacancies. Our results suggest that prospecting might serve several non-mutually exclusive functions. Further studies in non-saturated colonies could shed light on the functional aspects of prospecting.
Dataset DOI: 10.5061/dryad.6hdr7src0
Description of the data and file structure
Dataset Overview
This dataset contains the data required to replicate the analyses in Redondo et al. 2025.
In this work, we used detections of passive-integrated-transponder tagged (PIT-tagged) male floaters in a population of spotless starlings (Sturnus unicolor) to investigate how floater activity varied across breeding stages and how their visits influenced subsequent nest site selection. Floaters were captured before breeding season began and were marked with a PIT-tag that allowed us to monitor their visits to nests of conspecifics and future settlement.
We used long-term data (10 breeding seasons) on the intrusion behaviour and posterior nest site choice of male floaters in a population of spotless starlings. Our objective was two-fold:
- Describing the temporal patterns of prospecting in this species by monitoring nest intrusions by tagged individuals and examine the cues that may induce birds to prospect in particular boxes.
- Testing different hypotheses that have been proposed to explain prospecting (the alternative reproductive hypothesis, the foothold hypothesis, the public information hypothesis)
Files and variables
File: Prospecting_at_breeding_stages.csv
Description: contains the data related to the analyses of the factors influencing prospecting activity.
Variables
- event (factor): variable for identifying the nest and the breeding attempt.
- year (factor): year of observation.
- stage (factor): part of the breeding cycle where the observation was taken.
- nestlings (numeric): number of nestlings at the moment of observation.
- cs (numeric): clutch size
- bs6 (numeric): brood size when nestlings are 6 days-old.
- bs14 (numeric): brood size when nestlings are 14 days-old.
- bs18 (numeric): brood size when nestlings are 18-days old.
- brood_fledge (factor): binary variable. 0 = none of the nestlings fledged, 1 = at least one nestlings fledged.
- male_floaters_sl (numeric): number of floaters detected visiting the nest.
- dad_visits (numeric): number of times the male owner of the nest visited his nest-box.
- mum_visits (numeric): number of times the female owner of the nest visited his nest-box.
- parent_visits (numeric): sum of the visits the male and female owners visited their nest-box.
- duration (numeric): duration of the recording in minutes.
- wave (factor): whether the breeding attempt belonged to first clutches (1), reposition clutches (1.5) and second clutches (2).
- days_since_laying (numeric): days since the first egg was laid.
- days_since_hatching (numeric): age of the nestlings.
File: Prospecting_and_settlement.csv
Description: this dataset contains the data for the analyses aimed at determining the factors influencing settlement in relation to prospecting behaviour.
Variables
- order (numeric): file ID.
- ring (factor): identification number of each focal male.
- nest_dummy (factor): name/number of the nest box where a focal male was either detected or potentially could’ve been detected.
- distance (numeric): distance (in meters) between the centroid coordinates and the nest dummy nest.
- visited (factor): whether a male was actually detected visiting that nest box (0 = no, 1 = yes) the year before breeding.
- chosen (factor): whether a male was detected breeding in that nest box (0 = no, 1 = yes) the following year.
- chosen_dummy (factor): whether a male was detected breeding in that nest box (N = no, Y = yes) the following year.
- out_circle (factor): indicates whether the nest box was outside the median prospecting circle that was projected for each focal male.
- year (factor): the year of observation of the prospecting activity.
- first_brood_young_fledged (numeric): number of chicks that fledged from a nest during the first brood round.
- second_brood_young_fledged (numeric): number of chicks that fledged from a nest during the second brood round.
- annual_young_fledged (numeric): total number of chicks that fledged from a nest during a breeding season.
- second_brood_succeeded (factor): whether at least one chick fledged from a nest during the second brood round.
- body_condition (numeric): body condition (calculated as the residuals of weight versus size, the latter calculated from a PCA of tarsus, beak and wing length) of the last male individual known to have owned the nest box.
- age (numeric): age (in years) of the last male individual known to have owned the nest box
- ornamentation (numeric): Mean length (in mm) of three throat ornamental feathers) of the last male individual known to have owned the nest box.
- owner_not_return (factor): whether the last individual known to have owned the nest box has been detected again in the colony (0 = seen again; 1 = not seen again).
- feeding_rate (numeric): the mean number of times per hour a male attended their nest during the chick rearing period.
NA - Not applicable
Code/software
Language and Environment
R Environment for Statistical Computing
Version
R 4.0.3
Packages
car
glmmTMB
effects
parameters
effectsize
performance
emmeans
DHARMa
adehabitatHR
sf
geosphere
ggdist