Data from: Risk-taking behavior related to mercury contamination in a high Arctic seabird
Data files
Jan 13, 2026 version files 885.13 KB
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data2020_21AEcombined.csv
879.12 KB
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README.md
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Abstract
Understanding how animal personality traits are modified by environmental stressors, including chemical contaminants, is of increasing importance given rapid anthropogenic environmental change. In this context, we explored whether mercury (Hg) contamination is associated with neophobia and risk-taking behavior in little auks (or dovekies, Alle alle), an Arctic seabird facing altered Hg exposure due to climate change. To quantify parental risk-taking and neophobia behavior, we presented novel objects of different colors at little auks nests at Hornsund, Svalbard. We quantified latency of birds to enter the nest with food under control conditions and when confronted with novel objects. We related behavior to blood Hg and baseline corticosterone (CORT), as CORT might be modulated by Hg and affect behavioral stress responsiveness. We also determined repeatability and asked whether birds investing highly in reproduction displayed reduced neophobia. Little auks displayed neophobia, with latency to enter the nest increasing from ~40 to 80 sec on average in response to novel objects. Latency to enter was individually repeatable within and across control and novel object sessions, suggesting repeatability in cautiousness. However, neophobia (increased latency relative to controls) exhibited non-significant repeatability, perhaps due to habituation. Birds with elevated Hg for this population (range: 0.3-0.8 mg g-1 dry weight) took longer to enter the nest upon first appearance in control and novel object sessions, suggesting elevated cautiousness, but did not show higher neophobia or reduced habituation. CORT negatively correlated with neophobia. Findings support prior work suggesting that Hg might alter risk-taking behavior, calling for more work on this topic in animals at high Hg exposure risk.
https://doi.org/10.5061/dryad.m905qfv7z
In this study, we investigated neophobia and parental risk-taking behavior in little auks (Alle alle) breeding at Hornsund, Spitsbergen, Svalbard. We assessed whether these behaviors were individually repeatable and explored correlations with mercury (Hg) contamination and baseline corticosterone concentrations. In addition, we linked risk-taking and neophobia behavior to time activity budgets (TABs) and daily energy expenditure (DEE) derived from accelerometer data, which was derived in the later portion of the nestling period, after neophobia experiments were completed. Our results suggest a correlation between Hg contamination and parental risk-taking, but not neophobia or habituation behaviors. These findings call for more work regarding the behavioral effects of Hg contamination in animals at high Hg contamination risk.
Description of the data and file structure
To quantify neophobia and parental risk-taking, we quantified the latency of parent birds to enter the nest with food during control sessions (camera only) and up to three different novel object sessions, during which rocks wrapped in different colors of plastic (blue, red, yellow) were placed directly in front of nest entrances. When viewing video recordings to extract data, all appearances, disappearances, and entrances/exits of the nest by focal birds (marked with color bands) were recorded in datasheets. However, this data has been processed such that it contains lines only for first appearances with food (full gular pouch) and entrances into the nest that resulted in feeding (followed by exits with empty gular pouch). Latencies to enter and feed were calculated by subtracting appearance time from entrance/feed time. The relevant latency values are on lines for which Activity = appears with food. Thus, the dataset was subsetted to only contain these lines before conducting the mixed models described in our paper.
The dataset named "data2020_21AEcombined.csv" contains the following columns:
- count: counts up observations, 1-2620
- data_session: ID for the recording session, composite of nest ID and session type
- Session: Whether a session was control or experimental (novel object), and which replicate (1, 2, 3) of each session type is involved (Ctrl1, Ctrl2, Ctrl3, Exp1, Exp2, Exp3).
- CtrlExp: Whether a session was control or experimental (Ctrl, Exp).
- NestYearSession: Composite of nest ID, Year, and Session ID to uniquely define the recording session.
- Color: The color of the novel object (blue, red, yellow, none). Control sessions have "none" in this column.
- Order: The order in which control and experimental sessions were performed. 1-6, as 3 control and 3 experimental sessions were performed in some cases.
- SessionStartRealTime: Time at which the recording session started. 24 hr clock.
- SessionStartRealDate: Date on which the recording session started.
- DateRec: Date on which an observation was made.
- MinRec: Time at which an observation was made. 24 hr clock.
- Year: Year of observation (2020, 2021).
- realtime: Composite date and time of recording.
- Nest: Nest ID.
- BirdIDMark: Mark with colored paint identifying focal bird, if any.
- BirdIDRings: Color band combination of focal bird.
- BirdSession: Composite of bird and video recording ID.
- BirdSession2: Composite of bird ID, year and session ID.
- BirdYear: Composite of bird ID and year.
- Ring: focal bird band number.
- Activity: behavioral observation made at the denoted time, "appears with food" or "enters with food". Note that the dataset has been processed to only contain these values, as latencies were calculated between appear and enter times.
- CountAppear: Counts up the number of times a focal bird appeared within a single recording session.
- TotalTime: Total time of the recording session in seconds.
- TotalTimeD: Total time of the recording session in days.
- timeN: Numerical time at which the behavioral observation was made.
- appearenter: 1/0. Whether each appearance with food resulted in feeding (1) or did not (0).
- appearfood0: Whether each line indicates an appearance with food (1) or not (0).
- appearfood: Counts total appearances with food within a session.
- successfulfeed: Counts total successful feeding attempts within a session.
- failedfeed: Countal total failed feeding attempts within a session.
- Latency: Time between adjacent lines in seconds. Lines for which Activity = "appears with food" contain latencies to enter with food.
- feedRateDay: Feeding rate per day (feeds/day) within a session.
- sex: Sex of the focal bird (m = male, f = female).
- Hg: Blood mercury (Hg) in µg/g dry weight.
- CORT: Baseline plasma corticosterone (ng/mL).
- SMIf: Scaled mass index. See manuscript for details.
- DEE: Daily energy expenditure (kJ d-1g-1), calculated for focal birds from accelerometer data during the later nestling stage.
- feed.axy: Nestling provisioning rate (feeds/day) calculated for focal birds from accelerometer data during the later nestling stage.
- prop.col: Propotion of time activity budget (TAB) spent at the colony calculated for focal birds from accelerometer data during the later nestling stage.
- prop.water: Proportion of time activity budget (TAB) spent on the water surface (not diving) calculated for focal birds from accelerometer data during the later nestling stage.
- prop.dive: Proportion of time activity budget (TAB) spent diving calculated for focal birds from accelerometer data during the later nestling stage.
- prop.flight: Proportion of time activity budget (TAB) spent flying calculated for focal birds from accelerometer data during the later nestling stage.
- Ctrlfeedrate: Nestling provisioning rate (feeds/day) for focal birds during the first and longest control recording session.
Note regarding NA values: NA values indicate "not available."
Novel object presentation experiments, designed to test neophobia responses, were performed at little auk nests commencing when chicks were ~8-10 days old, at the height of the chick provisioning period. Experiments consisted of two different types of sessions, control and novel object sessions. During control sessions, we set up JVC video cameras ~5 meters from nests. Cameras could have been perceived as a novel object. However, to reduce this possibility cameras and tripods were black, a color present in the environment. Furthermore, cameras were set up far enough from the nest that birds could avoid immediate proximity to them when approaching the nest entrance. The camera tripods were also set up in the field long before the onset of the experiment. We preceded to record behavior using 1-sec timelapse mode, which compressed 72 hrs of continuous recording into 3 hrs, and facilitated conservation of memory space. Control sessions allowed us to assess bird behavior at nests in the absence of novel objects. During novel object sessions, which followed control sessions, a novel object consisting of a fist sized rock wrapped in blue, red, or yellow plastic (derived from plastic garbage bags) was placed as close as possible to nest entrances, without blocking the entrance.
When viewing videos to extract data, we recorded all sightings of the focal bird (marked with color bands) near the nest. However, this dataset has been processed such that it only contains lines for every first appearance at the nest with food (appears with food) and the corresponding entrance with food, resulting in feeding (enters with food). Latency times were calculated between first appearance with food and an entrance which resulted in feeding, as detailed in the manuscript. When conducting the analysis, we subsetted the dataset to only include lines for which Activity = "appears with food", as latency times (time to enter and feed) are on these lines.
This dataset also contains all available blood mercury (Hg, µg/g dw), corticosterone (CORT, ng/mL) data and scale mass index (SMI) data.