Warm winters lead to early breeding, increased breeding effort, but lower reproductive success, in a threatened habitat specialist
Data files
Jul 18, 2025 version files 273.13 KB
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Breeding_phenology_paper_code_RESUBMIT2.R
6.53 KB
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firstandlast.csv
54.27 KB
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meansbirddata.csv
49.97 KB
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neggs.csv
53.20 KB
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nestattempts.csv
53.02 KB
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Nfledg.csv
53.68 KB
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README.md
2.45 KB
Abstract
Climate warming is affecting the phenology and life-history of animals around the world. In birds, although warm winters have been shown to advance breeding dates and affect reproductive success in a diverse range of taxa, few studies document whether changes in breeding phenology are associated with variability in reproductive effort by the adults. We leverage a 40-year dataset on the demography of Florida Scrub-Jays (Aphelocoma coerulescens, FSJ) to investigate not only whether winter weather affects FSJ phenology and reproductive success, but also whether FSJs invest more effort in reproduction following warm winters. We found that FSJs bred early but fledged fewer offspring in springs following warm winters. This reduced reproductive success came at the expense of increased reproductive effort (N nests built, N eggs laid, and length of the breeding period across all attempts) by the breeders. Given the well-known tradeoff between reproductive effort and survival, we highlight an important but typically unrecognized cost of climate warming on birds, in a large, well-protected population of a threatened habitat specialist, as revealed by a long-term study.
https://doi.org/10.5061/dryad.12jm63z5g
Description of the data and file structure
Demography data are included that can be used to replicate the results provided in the manuscript. The code in the associated R script can be used to run the models with the associated datasets.
These demography data include
meansbirddata.csv : These data can be used to replicate models for nesting date and first nest success.
Columns within this dataset:
YEAR: Year of observation
TERR: Territory ID
meandaytempC: The mean temperature during the day in celcsius.
Helpers: Helpers present (Y/N)
Success: Nest successful (1,0)
incubDAY: Julian Day of incubation initiation
hatchDAY: Julian day of hatching
meandrought: mean drought index for preceding winter
nestattempts.csv: These data can be used to run the model looking at the number of nesting attempts and the mean winter temperatures.
YEAR: Year of observation
TERR: Territory ID
meandaytempC: The mean temperature during the day in Celsius.
Helpers: Helpers present (Y/N)
NestNum: Total number of nests built by pair in the season
neggs.csv: These data can be used to run the model looking at the number of eggs produced and the mean winter temperatures.
Columns within this dataset:
YEAR: Year of observation
TERR: Territory ID
Neggs: Eggs laid during the whole breeding season
meandaytempC: The mean temperature during the day in Celsius.
Nfledg.csv: These data can be used to run the model looking at the total number of fledglings produced by a pair in a year and the mean winter temperatures.
YEAR: Year of observation
TERR: Territory ID
meandaytempC: The mean temperature during the day in celcsius.
Helpers: Helpers present (Y/N)
nfldg: Number of fledglings produced by the group in the season
firstandlast.csv: These data can be used to replicate model 6 for the length of the breeding season.
YEAR: Year of observation
TERR: Territory ID
meandaytempC: The mean temperature during the day in celcsius.
Helpers.x: Helpers present (Y/N)
diff: Length of breeding season in days.
Breeding_phenology_paper_code_RESUBMIT2.R file included in the submission shows the model codes and relevant columns used for manipulating data.