DOI: 10.5061/dryad.mkkwh7162
title: Altitudinal differences in foraging decisions under predation risk in great tits

description: Foraging decisions under risk of predation are crucial for survival as
 predation risk can contribute to a reduction of food intake over time
 leading to a trade-off between starvation and predation. Environmental
 variation can provoke changes in food accessibility or predation risk that
 will in turn affect foraging decisions. Specifically, less predictable or
 harsher environments, such as those found at high elevation, should lead
 to more risk-prone foraging in order to prevent risk of starvation, but
 empirical confirmation of this hypothesis is lacking. In the current
 study, we used video playbacks combined with an automatic feeder to
 measure continuous foraging choices between control and predator videos by
 wild great tits originating from high and low elevations and tested under
 controlled conditions. Great tits discriminated between two conditions
 representing differences in predation risk and visited the feeder less
 frequently when a predator was shown. Moreover, we found that birds from
 low elevation populations were more risk-averse and visited the feeder
 significantly less when a predator video playback was broadcasted compared
 to high elevation individuals. This elevation related contrast was also
 dependent on the season, body mass and fat reserves of individuals, and
 was more marked in females. Furthermore, adults visited the feeder less in
 the presence of a predator compared to yearlings. These results are
 consistent with predictions from life history theory and
 starvation-predation trade-off hypotheses and could have implications for
 individual movements and population dynamics in changing environments.
description: # Altitudinal differences in foraging decisions under predation risk in
 great tits These datasets are used to investigate altitudinal differences
 in foraging decisions under predation risk in great tits. Three successive
 datasets were used to that aim: **df.PredAbundance** Measurement of
 predator abundance per elevation using camera trap Presentation of
 variables: * Elevation: elevation above see level in meters of the
 location of the camera trap * ElevationClasses: elevation sorted by
 category: 100-600; 600-1000; 1000-1500 * PredatorType: type of predator
 identified on cameratrap, either avian (AvianPred) or mammal (MammalPred)
 * CamTrap: identity of the camera trap used. * IndividualCount: number of
 predators identified * Year: year of measure of the predator abundance
 (either 2016 or 2017) **df.PredElevation** Measurement of the number of
 visits to a feeder depending on video playbacks for various great tits
 Presentation of variables: * ID: Bird identity number composed of 7
 characters * Elevation: Elevation of origin of each individual based on
 the site of capture, either High or Low * Site: Site of capture of each
 individual (AT, AU, MJ, VI) * Sex: Sex of each individual, either male (M)
 or female (F) * Age: Age of each individual, either adult or yearling.
 Information was not measured for one individual due to difficulty to age
 it (labelled as NA). * TarsusS: scaled value of tarsus measured at capture
 (initially in g) * Weight.inS: scaled value of weight at capture
 (initially in g). Information was not measured for three individuals due
 to technical issues (labelled as NA). * Weight.outS: scaled value of
 weight at release (initially in g) * FatS: scaled value of fat reserves at
 capture (4 level scale, see main text for details). Information was
 missing for four individuals (labelled as NA). * ExploS: scaled value of
 exploration score measured at first release in aviaries (number of
 movements during a 3-min period). Information was not measured for two
 individuals due to time constraints (labelled as NA). * Season: Season of
 capture of each individual, either Fall or Winter * Batch: Batch of
 capture of each individual (8 levels) * V_blackbird: Number of visits per
 day during control video playbacks * V_sparrowhawk: Number of visits per
 day during predator video playbacks The weight at capture and the
 **df.PredPeriod (supplementary materials)** Measurement of the number of
 visits to a feeder depending on video playbacks and period of the day for
 various great tits Presentation of variables: * ID: Bird identity number
 composed of 7 characters * V_blackbird: Number of visits per period during
 control video playbacks * V_sparrowhawk: Number of visits per period
 during predator video playbacks * Period: Separation of the experiment in
 6 1-hour period (from 1 to 6)