Authors

Sara Isgate(1,2), Caitlin Honus(1), Gabriel Casanova(1), Bailey Betcher(1), Julian Avery(1), and Jason Keagy(1)*

(1)Department of Ecosystem Science and Management, The Pennsylvania State University
(2)Department of Biology, Indiana University

*corresponding author: Jason Keagy, 410 Forest Resources Building, Penn State University, University Park, PA 16802; phone: 814-699-0973; email: keagy@psu.edu

Abstract

We used a mechanical operant conditioning device to understand how acute (48-hour) anthropogenic noise may affect Eastern bluebird (Sialia sialis) cognitive performance. Mated pairs were presented with the operant device, featuring an active and inactive lever, on the front of their nest box during peak nestling provisioning. Subjects were required to perch on the active (correct) lever in the presence or absence of anthropogenic noise (natural gas compressor station noise, n = 22 birds per treatment) to access nestlings. We quantified cognitive performance, various behaviors that might influence cognitive performance (motivation to feed nestlings, approach latency, exploration, and persistence), nestling condition, and eventual fledging success. There was no significant effect of acute noise on cognitive performance. However, other behaviors were influenced by noise. For example, although both sexes in the control group fed nestlings less across the two days of the experiment, females exposed to noise decreased feeding even more, and males exposed to noise appeared to compensate. Birds in the silent treatment reduced approach latency over time, but birds in the noise treatment increased approach latency over time. Finally, problem-solving time significantly decreased over trials, suggesting learning occurred.

Description of the data and file structure

We include in this submission all data and code used for the manuscript.

bluebird_noise_cognition.csv

Comma-delimited text file with all data used for the manuscript. Data was collected in the spring and summer of 2023 (March-August) at Penn State University’s Russell E. Larson Agricultural Research Center in Pennsylvania Furnace, Pennsylvania

The CSV contains the following columns:

1. sex - sex of parent (male or female)
2. Day - day of operant trial (1 = 1st or 2 = 2nd)
3. Date - date of operant trial (M/D/YY)
4. Box - nest box number (see supplemental material for map)
5. Sound.treatment - whether noise was played or not (Silent or Noise)
6. Active-lever - which lever opened the door (Right or Left)
7. Band.ID - USGS metal band ID number; if none, then the box number and sex
8. Pair.ID - Band.ID of female and Band.ID of male separated by an underscore
9. Nest.date - date of nest (M/D/YY)
10. First.egg - date of first egg (M/D/YY)
11. Number.eggs - number of eggs
12. First.hatch - date first egg hatched (M/D/YY)
13. Number.hatchlings - number of hatchlings
14. Hatchling1.Wt - weight of first hatchling measured on PHD 11 (g)
15. Hatchling2.Wt - weight of a second hatchling measured on PHD 11 (g)
16. Hatchling3.Wt - weight of a third hatchling measured on PHD 11 (g)
17. First.fledge - date of first fledgling leaving nest (M/D/YY)
18. Number.fledglings - number of fledglings
19. Hatchling1.Tarsus - tarsus length of first hatchling measured on PHD 11 (mm)
20. Hatchling2.Tarsus - tarsus length of a second measured hatchling on PHD 11 (mm)
21. Hatchling3.Tarsus - tarsus length of a third measured hatchling on PHD 11 (mm)
22. Eyes.open - date when eyes of hatchlings opened (M/D/YY)
23. Eyes_PHD - post-hatch day when the eyes of hatchlings opened
24. Pin.feathers - date when feather tips seen at tips of sheaths (M/D/YY)
25. PF_PHD - post-hatch day when feather tips seen at the tips of sheaths
26. Color.code - color band combination
27. R.wing.flat - right wing length measured held down flat (mm)
28. R.wing.curved - right wing length measured not held down flat (mm)
29. Weight - weight (g)
30. Capture.date - date captured and measurements taken (M/D/YY)
31. R.Tarsus - right tarsus length (mm)
32. PreCog_Start - time parental feeding observation begun (H:MM AM/PM ET)
33. PreCog_Motivation - number of feedings during pre-cognition feeding observation
34. PreCog_Neophobia - time to approach nest box during pre-cognition feeding observation (sec)
35. PreCog_Weather - weather at start of pre-cognition feeding observation
36. PreCog_Temp - temperature at start of pre-cognition feeding observation (F)
37. Cognition_Start - time cognition observation begun (H:MM AM/PM ET)
38. Cognition_Weather - weather at start of cognition observation
39. Cognition_Temp - temperature at start of cognition observation (F)
40. Neophobia_Cog - time to approach nest box during cognition observation (sec)
41. Pers_Result - what happened after initial visit to box (leave or enter the box fully)
42. Pers_Score - seconds between first arriving at box and either leaving or entering box fully (sec)
43. Exploration_Score - seconds spent interacting with box (sec)
44. PS_Result - whether bird solved or failed to solve the operant device that day (Solved/Failed)
45. PS_Result_Overall - whether bird solved (at least one day) or failed to solve (both days) the operant device over the course of both days (Solved/Failed)
46. PS_Score - time to solve (sec); N/A if did not solve

Unless otherwise noted, N/A represents missing data

• For tarsus length, we measured photos of bent legs with toes also bent using FIJI.
• A line was drawn from the beginning of the foot (base of toes, there is a change in scale morphology here) to the point perpendicular to the end of the tarsus.
• The third point was set as the end of the tarsus, the inner bend of the tibiotarsal articulation.
• The vertex of this angle was then adjusted so that the angle read as close to 90 degrees as possible, and the length of the line along the leg was measured.

Code/Software

bluebird_noise_cognitionR3.R

To recreate all of our analyses and figures, execute this code. Code by Sara Isgate and Jason Keagy. Last run 14 January 2026 using R version 4.5.1 (2025-06-13) in RStudio Version 2025.05.0+496 (2025.05.0+496)

Packages used include:

• lme4 version 1.1-37
• lmerTest version 3.1-3
• car version 3.1-3
• tidyverse version 2.0.0
• Hmisc version 5.2-3
• rptR version 0.9.23
• corrplot version 0.95
• DescTools version 0.99.60
• emmeans version 2.0.1
• MuMIn version 1.48.11