DOI: 10.5061/dryad.4qrfj6qps
title: Response to intruder number is related to quantity discrimination performance in a wild bird

description: Quantity discrimination abilities are considered a valuable skill for many
 aspects of life, including foraging, predator avoidance, and intergroup
 contests. Two types of experiments are often utilised to detect such
 abilities in animals: cognitive tasks in which individuals must choose
 between two quantities of food, and playback experiments of the
 vocalisations of differing numbers of intruding individuals. To date, no
 study has investigated whether individual performance in these two types
 of experiments is related. We presented wild Western Australian magpies
 (Gymnorhina tibicen dorsalis) with both a spontaneous quantity
 discrimination cognitive task and a playback experiment, to investigate
 quantity discrimination abilities, and to explore if performance on these
 experiments is related. We found that magpies (a) selected the greater
 quantity of food in the cognitive task and (b) responded more strongly to
 the playback of three callers compared to one caller, suggesting this
 species possesses quantity discrimination abilities. Individual
 performance on these two experiments was negatively correlated, with
 magpies that performed better on the cognitive task spending less time
 vigilant following the three-caller playback compared to magpies that
 performed worse. Our results highlight the importance of exploring the
 relationship between performance in a cognitive task and ecologically
 relevant behaviours, as this has the potential to offer profound insights
 into cognitive ecology.
description: # Response to intruder number is related to quantity discrimination
 performance in a wild bird **Blackburn G; Ashton BJ; Hunter H; Ridley AR**
 **Corresponding author email:**
 [g.blackburn@cqu.edu.au](mailto:g.blackburn@cqu.edu.au) Data was collected
 between March and July in 2022 and 2023 on an established study population
 of Western Australian magpies located in Crawley and Guildford, Perth,
 Western Australia. **Dataset DOI:**
 [10.5061/dryad.4qrfj6qps](10.5061/dryad.4qrfj6qps) ## Description of the
 data and file structure This study investigates the quantity
 discrimination of Western Australian magpies using both a cognitive task
 and a playback experiment. Data includes cognitive testing from two years
 (2022 and 2023) on a spontaneous quantity discrimination task, and
 playback experiments from one year presenting birds with the territorial
 songs of 1, 2, and 3 calling extra-group conspecifics. ### Files and
 variables #### File: repeatabilityoftotalscores.csv **Description:** This
 file is used to test for long-term repeatability in cognitive performance.
 ##### Variables * bird: bird identity * group: group identity * pass: the
 total number of times that birds chose the larger quantity of food out of
 the total of 45 trials (15 2 vs 3 trials, 15 2 vs 4 trials, and 15 2 vs 5
 trials). * fail: the total number of times that birds chose the smaller
 quantity of food out of the total of 45 trials (15 2 vs 3 trials, 15 2 vs
 4 trials, and 15 2 vs 5 trials). * year: year of testing #### File:
 2023NA.csv **Description:** This file is used to check for a possible side
 bias in the control 2 vs 2 trials, as well as to check if birds are
 selecting the larger amount more often than random in the 2 vs 3, 2 vs 4,
 and 2 vs 5 trials. ##### Variables * BIRD.ID: bird identity * GROUP: group
 identity  * COMBINATION: ratio (2 v 2, 2 v 3, 2 v 4, 2 v 5) * SIDE CHOICE:
 whether the individual chose the board on their left or their right *
 CHOOSE LARGER?: whether individuals chose the larger quantity of food ####
 File: 2023NA_no2v21.csv **Description:** Control 2 vs 2 trials have been
 removed, and this file contains only 2 vs 3, 2 vs 4, and 2 vs 5 trials.
 ##### Variables * BIRD.ID: bird identity * GROUP: group identity  * SEX:
 sex of the bird  * A_GROUP_SIZE: adult group size * WEATHER: weather
 condition (cloudy or clear) * TEMPERATURE: temperature during testing (°C)
 * NEOPHOBIA: latency to interact with the task (seconds) *
 COMBINATION: ratio (2 v 2, 2 v 3, 2 v 4, 2 v 5) * SIDE CHOICE: whether the
 individual chose the board on their left or their right * CHOOSE
 LARGER?: whether individuals chose the larger quantity of food * MASS:
 average body mass of the bird (g) * Feffort: average foraging effort of
 the bird (proportion of time spent foraging out of focal time) *
 Fefficiency: average foraging efficiency of the bird (grams of prey caught
 in time spent foraging) #### File: NAPB.csv **Description:** This file is
 used to investigate factors affecting response to playbacks of one, two,
 and three callers. ##### Variables * BIRD.ID: bird identity * GROUP: group
 identity  * SEX: sex of the bird  * A_GROUP_SIZE: adult group size *
 TREATMENT: playback treatment (one caller, two callers, or three callers)
 * TRACK_ORDER: order in which tracks were presented to individuals *
 SEX_RATIO: composition of playback call (focal birds' sex / total
 callers in treatment) * CHORUS_LENGTH: length of carol or chorus presented
 in the playback track (seconds) * VIGPREPB: time spent vigilant
 pre-playback (seconds) * VIGPOSTPB: time spent vigilant
 post-playback (seconds) * SONGS: number of carols sung post-playback *
 APPROACHSPEAKER?: whether individuals approached the speaker post-playback
 #### File: NAPB_cog.csv **Description:**  This file is used to investigate
 if performance on the numerical assessment cognitive task is related to
 response to numerical assessment playbacks. ##### Variables *
 BIRD.ID: bird identity * GROUP: group identity  * SEX: sex of the bird  *
 AGSIZE: adult group size * TREATMENT: playback treatment (one caller, two
 callers, or three callers) * TRACK_ORDER: order in which tracks were
 presented to individuals * SEX_RATIO: composition of playback call (focal
 birds' sex / total callers in treatment) * CHORUS_LENGTH: length of
 carol or chorus presented in the playback track (seconds) * VIGPREPB: time
 spent vigilant pre-playback (seconds) * VIGPOSTPB: time spent vigilant
 post-playback (seconds) * PROPVIG: proportion of time spent vigilant
 post-playback * SONGS: number of carols sung post-playback *
 APPROACHSPEAKER?: whether individuals approached the speaker post-playback
 * TOTAL_SCORE: total numerical assessment score #### File:
 rawmotivationmetrics.csv **Description:** This file contains the raw data
 used to calculate average body mass, foraging effort, and foraging
 efficiency for the 2023 cognitive tests. Birds were focalled and weighed
 between 1 and 3 times during the testing period, and these measures were
 averaged to give average foraging effort, foraging efficiency, and body
 mass over the 15-day testing period. ##### Variables * BIRD.ID: bird
 identity * GROUP: group identity  * SEX: sex of the bird  * mass1, mass2,
 and mass3: raw body mass measurements (g) * Feffort1, Feffort2, and
 Feffort 3: raw foraging effort metrics calculated from focal (proportion
 of time spent foraging out of focal time) * Fefficiency1, Fefficiency2,
 and Fefficiency3: raw foraging efficiency metrics calculated from
 focals (grams of prey caught in time spent foraging) * MASS
 (average): average body mass of the bird (g) * Feffort (average): average
 foraging effort of the bird (proportion of time spent foraging out of
 focal time) * Fefficiency (average): average foraging efficiency of the
 bird (grams of prey caught in time spent foraging) * no.focals: number of
 focals for that bird used to calculate average metrics