DOI: 10.5061/dryad.v41ns1s3q
title: Extended incubation recesses in Sanderlings are impacted by temperature and body condition

description: Complex incubation strategies have evolved to solve the trade-off between
 parent survival and care for their eggs with often brief departures
 (recesses) that maximise egg survival or infrequent extended recesses
 maximising adult condition. Here we examined incubation behaviour of
 Sanderlings (Calidris alba), a species that exhibits both bi- and
 uniparental incubation behaviour. During 11 breeding seasons in Greenland,
 we have quantified incubation variability with thermologgers placed in
 nests. We estimated the impact of environmental conditions and individual
 characteristics on the occurrence and the duration of recesses. We found
 that extended recesses are a unique feature of uniparentals, and their
 frequency and duration increased in colder temperatures. The relationship
 was mediated by body condition, with individuals in poor condition
 performing longer extended recesses in colder temperatures. This suggests
 that extended recesses may represent a shift towards self-maintenance at
 the expense of the egg care, allowing birds to continue incubating under
 unfavourable conditions. Our study illustrates how extended recesses may
 be a key breeding strategy to overcome high energetical costs associated
 with incubation. Quantifying such behavioural flexibility paves the way
 for tracking future behavioural responses of individuals in the face of
 changing environments.
description: This dataset (2011-2021) is a long-term monitoring based on
 fieldwork in Greenland. The field team collects behavioural data at
 Sanderling nests by putting thermologgers in the nest cups during the
 incubation period. Loggers are then retrieved at the end of the breeding
 season and data is processed with TinyTag Explorer Software. One dataset
 is at the recess (departure from the nest to forage) scale, and the other
 is at the daily scale (see Methods). Datasets are used in conjunction with
 the provided R code.
description: # Extended incubation recesses in Sanderlings are impacted by temperature
 and body condition ##
 Description of the data and file structure We collected behavioural
 information on Sanderlings' incubation ecology. We collected
 information on their incubation recesses at two different time scales.
 Firstly, we collected information at the recess scale: the recess is the
 statistical unit. Secondly, we pooled these recesses at a daily scale. For
 that, we focus on the Total Duration of Recesses (TDR), summing all the
 recesses during a 24h period. Therefore, we obtained two datasets;
 "Recesses", at the recess scale, and "TDR" at the
 daily scale. Description of the column names: ‘Recesses.txt’ dataset.
 ·       date: date-hour of each recess performed YY-MM-DD HH:MM:SS.
 ·       recess_size_max: duration of each recess in minutes. ·      
 recesslong: 0/1 for each recess, to describe if this recess is extended (≥
 120min) or short (&lt;120min). ·       strategy: description of the nest’s
 status; UNI if the nest is uniparental since the beginning of the
 incubation; UNISWAP if the nest started the incubation with both parents
 incubating and switch strategy during the incubation to become uniparental
 (see Methods). ·       year: Year of data acquisition ·       nest_id:
 unique combined ID of the nest, composed of the first four letters of the
 species name (SAND), the year, and the field nest ID. ·       sexe: sex of
 each individual. Cells containing *NA *are individuals for which the sex
 was not available due to lack of morphometric measures. ·      
 body_condition: body condition of each individual calculated with the Peig
 and Green’s index (2009) (see Methods). Cells containing *NA *are
 individuals for which the body condition was not available due to lack of
 morphometric measures. ·       nest_age: incubation stage. The first day
 of incubation is assigned day 0, the second day of incubation is assigned
 day 1, third day 3… to keep track of the incubation advancement. ·      
 previous_temperature24: Ground temperatures (ºC) averaged during the 24
 hours preceding the hour of the recess. If one hour or more was missing
 during the previous 24h, the mean could not be calculated, and *NA *was
 assigned to the cell (see Methods). ·       previous_temperature12: Ground
 temperatures (ºC) averaged during the 12 hours preceding the hour of the
 recess. If one hour or more was missing during the previous 12h, the mean
 could not be calculated, and *NA *was assigned to the cell (see Methods).
 ·       previous_temperature6: Ground temperatures (ºC) averaged during
 the 6 hours preceding the hour of the recess. If one hour or more was
 missing during the previous 6h, the mean could not be calculated, and *NA
 *was assigned to the cell (see Methods). ·       previous_temperature2:
 Ground temperatures (ºC) averaged during the 2 hours preceding the hour of
 the recess. If one hour or more was missing during the previous 24, the
 mean could not be calculated, and *NA *was assigned to the cell (see
 Methods). ·       previous_temperature1: Ground temperatures (ºC) of the
 hour preceding the hour of the recess. *NA* was assigned when the
 preceding temperature was not available. day: each recess classified as
 being during daytime (9h-17h) or night time. Despite permanent light, most
 Arctic species keep a diurnal rhythm. ## Code/Software We used R to
 process the data, R version 4.3.0. All packages used are described in the
 R code.