https://doi.org/10.5061/dryad.2bvq83bws

Fledge dates and times of Leach's Storm-Petrel chicks from Gull Island, Witless Bay Ecological Reserve, Newfoundland and Labrador, Canada, were determined using a custom-built passive integrated transponder (PIT) system. 123 chicks were tracked in 2017, 2018, 2021, and 2022. The median fledge date was October 10, and the median fledge time was 1.6 h after sunset. We also examined whether fledging date and time were associated with moon phase and incident illumination. Chicks fledged randomly with respect to moon phase and incident illumination.

Description of the data and file structure

all_chicks.csv - the date and time of each detection of a Leach's Storm-Petrel chick in its burrow by the PIT tag system.

• BurrowID: the name of the burrow
• BandNo: the unique number on the steel Canadian Wildlife Service band for the chick
• DateTime: The date and time of the read (bird passing through the burrow entrance) in NDT
• Plot: identification number of the plot that the burrow and chick are in
• year: The year of each read (2017 - 2022)

chick_banding.csv - Morphometric information taken when the chick was banded and tagged with a PIT tag. Not all chicks that were banded have an associated tag as they were too small for tagging at this time.

• Date: The date the chick was captured and measured
• Tag deployed: Whether a PIT tag was deployed on the chick at this date. Empty cells indicate that a tag was not deployed on the chick on this date.
• BurrowID: the name of the burrow
• Plot: identification number of the plot that the chick was banded in
• BirdWt: Weight of the chick in grams
• Wing: length of the wing chord in mm. The wing length of one tagged chick was not measured and this cell is left blank.
• BandNo: the unique steel Canadian Wildlife Service band for the chick
• Year: the year the chick was banded in

Sharing/Access information

Data were derived from the following sources:

• Cloud Cover - https://cds.climate.copernicus.eu/cdsapp#!/dataset/satellite-cloud-properties?tab=form
• Strandings (thesis) - 10.13140/RG.2.2.21135.66723 (contact the author: tburt@mun.ca)
• Moon Phase and Incident Illumination - derived from the package moonlit (Smielak, M. 2023. Predicting moonlight intensity on the ground for a given place and time. https://github.com/msmielak/moonlit)

Code/Software

All code is written and run in R version 4.2.2. Markdown files containing the code are described below. Run ConsolidateData.Rmd first, followed by LESPChickFledging.Rmd.

ConsolidateData.Rmd - R markdown code to process and combine data files. Cloud cover data for the study period and location were obtained from https://cds.climate.copernicus.eu/cdsapp#!/dataset/satellite-cloud-properties?tab=form. Precise moon phase and moon illumination data at the exact time of fledging were obtained using the R package moonlit. Data regarding strandings of Leach's Storm-Petrels at Bay de Verde, Newfoundland and Labrador, Canada, were collected and analyzed for the Undergraduate thesis of TV Burt (manuscript in prep). These data were used here with permission for the creation of one figure.

LESPChickFledging.Rmd - R markdown code for analysis of PIT tag data for the manuscript "Small tube-nosed seabirds fledge on the full moon and throughout the lunar cycle". All data used for this manuscript were collected by the authors and are available on this repository or were obtained with permission and cited within the code.