DOI: 10.5061/dryad.4f4qrfjmv
title: Caught out in the cold: Mallard survival decreased during an extreme climatic event

description: Extreme climatic events (ECEs) can have profound impacts on individual
 fitness, affecting survival directly or indirectly. Late winter ECEs may
 be especially detrimental to fitness due to limited food resources and
 increased energetic requirements during this time. A polar vortex
 disruption ECE descended upon the mid-continental United States during
 7–20 February 2021 with temperatures as low as −29ºC in areas concurrent
 with ongoing research on mallard (Anas platyrhynchos) movement ecology and
 survival in Arkansas, Louisiana, and Tennessee, USA spanning winters
 2019–2022. Therefore, we opportunistically evaluated the effects of
 individual characteristics and latitude on daily survival during the ECE.
 We extended the survival analysis into March to test for lasting effects
 of the ECE on survival. We tracked 181 GPS-marked mallards during February
 2020, 256 in February 2021, and 324 in February 2022. We documented 22
 mortalities during the February 2021 ECE (i.e., 9%), but only 6
 mortalities during February 2020 (i.e., 2%) and 2022 (i.e., 1%) when
 conditions were average. February survival (e.g., 28-day survival) during
 the ECE was 0.908 (85% CI = 0.879–0.937) but was 0.982 (85% CI = 0.973 –
 0.991) during the two non-ECE Februaries. The ECE effect on survival was
 isolated to February and did not affect March survival. Mallards were 5.4
 times more likely to die during the ECE in 2021 compared to non-ECE
 Februaries. Although large-bodied waterfowl appear cold-tolerant and less
 sensitive to polar vortex disruptions compared to smaller-bodied
 passerines, direct mortalities can occur if conditions are severe enough
 and persist, highlighting the need to consider the influence of ECEs on
 common, seemingly robust species in future global climate change
 scenarios.
description: # Caught out in the cold: Mallard survival decreased during an extreme
 climatic event GENERAL INFORMATION 1. Title of Dataset: Caught out in the
 cold: Mallard survival decreased during an extreme climatic event. 2.
 Author Information: Abigail G. Blake-Bradshaw, School of Environmental
 Studies, Tennessee Tech University, Cookeville, TN 38505, USA Nicholas M.
 Masto, School of Environmental Studies, Tennessee Tech University,
 Cookeville, TN 38505, USA Cory J. Highway, Department of Biology,
 Tennessee Tech University, Cookeville, TN 38505, USA Allison C. Keever,
 Department of Biology, Tennessee Tech University, Cookeville, TN 38505,
 USA Paul T. Link, Louisiana Waterfowl Working Group, Lafayette, LA 70508,
 USA Jamie C. Feddersen, Tennessee Wildlife Resources Agency, Nashville, TN
 37211, USA Heath M. Hagy, United States Fish and Wildlife Service,
 Bismarck, ND 58501, USA Douglas C. Osborne, College of Forestry,
 Agriculture, and Natural REsources, University of ARkansas at Monticello,
 Monticello, AR 71656, USA Bradley S. Cohen, Department of Biology,
 Tennessee Tech University, Cookeville, TN 38505, USA 3. Date of Collection
 2019-2022 4. Geographic Location of data collection: Arkansas, Louisiana,
 and Tennessee, USA 5. Information about funding sources that supported the
 collection of the data: This project was funded by Wildlife Restoration
 Grants administered by the U.S. Fish and Wildlife Service, Wildlife and
 Sport Fish Restoration Program: Partnering to fund conservation and
 connect people with nature and the U.S. Fish and Wildlife Service National
 Wildlife Refuge System, Southeast Region. DATA & FILE OVERVIEW 1.
 Description of dataset: These data were collected from GPS marked mallards
 to examine wintering ecology of mallards. These data were
 opportunistically used to evaluate mallard survival during an extreme
 climatic event, polar vortex disruption, that occurred during February of
 2021 in the middle of three separate mallard tracking studies. 2. File
 List: surv_datum: daily survival histories of mallards with variables used
 in analysis METHODOLOGICAL INFORMATION We captured male and female
 mallards from November through January 2019–2022 . We placed individually
 marked United States Geological Survey aluminum leg bands on all captured
 waterfowl. We also affixed solar rechargeable and remotely programmable,
 OrniTrack-20 Global Positioning System-Global System for Mobile (GPS-GSM)
 transmitters (Ornitela, UAB Švitrigailos, Vilnius, Lithuania) on mallards
 of all age and sex classes. We took GPS locations at 1- to 2-hour
 intervals depending on transmitter battery level. We censored the first 4
 days of GPS fixes to allow ducks to recover from capture and handling. We
 monitored ducks from first capture until transmitters failed to report GPS
 fixes (i.e., battery malfunction), ducks were harvested by hunters, or GPS
 fixes and tri-axial accelerometry sensors indicated mortality.
 DATA-SPECIFIC INFORMATION FOR: surv_datum.csv 1. Number of Variables: 11
 2. Variable List: 1. trackId: individual mallard identification 2. date:
 date of survival history 3. time1: start of day in seconds 4. time2: end
 of day in seconds 5. mortality: binary variable representing whether an
 individual mallard experienced mortality on that day 6. ECE: binary
 variable representing whether it was an Extreme Climatic Event (ECE) year
 or not (nonECE) 7. sex: binary variable representing sex of individual
 mallard (female or male) 8. age_adjust: binary variable representing age
 (juvenile or adult) 9. avg_lat: daily average latitude for individual
 mallards on that date 10. mass_diff_sex: sex-corrected mass estimate
 whereby average mass was subtracted from each individual's mass.
 Negative values represent masses lighter than average and positive values
 represent masses heavier than average. 11. month: variable representing
 month (2 = February, 3 = March)