DOI: 10.5061/dryad.hmgqnk9xb
title: Incubation behaviour in a double-nesting alpine bird Alectoris graeca saxatilis: Similar nest attendance by males and females

description: In birds with double-nesting and uniparental incubation, such as the rock
 partridge (Alectoris graeca saxatilis), the male incubates one clutch,
 while the female incubates the other. A previous study found no
 significant difference in hatching and predation rates on Alpine rock
 partridge nests incubated by each sex. We therefore hypothesized that the
 incubation rhythms of both sexes would be similar. To test this, we
 monitored the incubation patterns of 40 nests incubated by females and 41
 nests incubated by males in the French Alps between 2011 and 2020.
 Temperature loggers were installed within and outside the nests to record
 internal and ambient temperatures at 3-minute intervals. Incubation recess
 timing and duration were inferred from the analysis of temperature curves.
 We employed statistical modelling to assess the effects of the incubating
 bird’s sex, minimum ambient temperature, incubation day, clutch size and
 recess rank on various incubation parameters. The timing, total duration,
 and number of recesses, as well as nest temperature, were found to be
 similar between the sexes. On average, birds took 2.5 recesses per day,
 with each recess lasting approximately 75 minutes. Overall nest attendance
 was ≃ 88%. Recesses occurred throughout the day, with a peak after sunrise
 and a second, less pronounced peak before sunset. Nocturnal recesses were
 rare and resulted from disturbances to the incubating bird. Modelling
 results indicated only slight differences in the mean recess duration
 between the sexes throughout the incubation period. Further analysis
 showed that both sexes adjusted their incubation rhythms in a similar
 manner in response to the progress of incubation and to daily minimum
 temperatures. Cold temperatures may compel parents to spend more time
 foraging to meet their energy needs. Rock partridges exhibited lower nest
 attendance compared to grouse species inhabiting cold environments, likely
 due to their relatively lower body reserves.
description: # Incubation behaviour in a double-nesting alpine bird Alectoris graeca
 saxatilis: Similar nest attendance by males and females Dataset DOI:
 [10.5061/dryad.hmgqnk9xb](10.5061/dryad.hmgqnk9xb) ## Description of the
 data and file structure #### File: recess-data_JAB.csv
 **Description:** this file includes the data used for analysis of
 incubation rhythms of rock partridges. It consists of recesses as rows and
 identifiers along with variables as columns. **Variables** * oiseau: name
 of the incubating bird * rang: rank of the recess within the day *
 Duree_sortie: duration of the recess, in minutes * date: number of days,
 counted from May 31st * debut: recess start time from sunrise, in minutes
 * Tmax_in: nest temperature, in °C, at recess initiation * Tmin_in: nest
 temperature, in °C,  at return time on the nest * annee: monitoring year
 of the incubating bird * oiseau_an_date: name of the bird_year_date *
 oiseau_an: name of the bird incubating a nest_one year (used as nest
 identifier) * sexe: sex of the incubating bird (male *vs.* female) *
 annee_F: year * Tminj: minimal daily ambient temperature, in °C  * ponte:
 complete clutch size * PP: camera trap (1 if present, 0 if absent) *
 deb_couv: day of nest incubation initiation, counted from May 31st * mois:
 month * aube.lever_soleil: time between dawn and sunrise, in minutes *
 lever_soleil.crepuscule: Time between sunset and dusk, in minutes * phase:
 nocturnal vs. diurnal * lever_minute: time of sunrise, in minutes *
 debut.aube: time between the start of the recess and dawn, in minutes *
 debut_0h: time between the start of the recess and the start of the day,
 in minutes * temps_jour: total duration of recesses throughout the day, in
 minutes, including both diurnal and nocturnal phases * jour_couv:
 Incubation day, defined as the number of days since incubation began for a
 given nest * temps_diurne: total recess duration, i.e. the cumulative
 amount of time spent off the nest during the diurnal phase *
 temps_nocturne: total recess duration, i.e. the cumulative amount of time
 spent off the nest during the nocturnal phase * nb_sorties_jour: number of
 recesses per day * nb_sorties_diurne: number of diurnal recesses per day
 **Code/software** The data can be viewed using LibreOffice or R (version
 4.4.1).