Data from: Fledging success peaks later than insect prey biomass in two aerial insectivores: evaluating potential phenological mismatch and fitness consequences
Data files
Jan 23, 2026 version files 24.71 KB
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individualoffsets.csv
2.82 KB
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insect.csv
7.96 KB
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README.md
5.63 KB
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RMarkOS.csv
4.40 KB
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RMarkWE.csv
3.89 KB
Abstract
These are data on timing (phenology) of bird breeding stages and success for the Olive-sided Flycatcher and the Western Wood-Pewee (aerial insectivorous birds) breeding in Yukon, Canada. The dataset "insect" has the ordinal date, average length of insects, the biomass estimate, temperature (C) for the day the insect sample was taken (please note that traps were open for several days), the proportion of Diptera (order of Flies) and Hymenoptera (order of bees, wasps, and flying ants) in each sample, the breeding or nesting "score" for each bird species. The nesting score is based on breeding progression days - an unpaired male bird would receive a "1", paired a "2", incubation a "3", etc., and then these are summed across each day. The datasets entitled "RMarkOS" and "RMarkWE" are the data used in RMark analyses that examine the daily survival probability of each nest based on day or age, timing (offset from insect abundance), or environmental variables (such as distance to water).
Dataset DOI: 10.5061/dryad.sj3tx96hx
Description of the data and file structure
Data were collected in Yukon, Canada between mid-May and August in the breeding seasons of 2013 - 2017 by observational methods examining nesting timing and success of breeding birds (using 30 minute observations on 10 - 20 breeding pairs per day) (the birds included were the Olive-sided Flycatcher (Contopus cooperi) and the Western Wood-Pewee (Contopus sordidulus) and capturing insects on the territories of these birds using hanging Malaise traps with 1.1 m panels that intercept flying insects. Transect data were collected to capture dragonfly data (Odonata) by walking 50 m transects (less than 150 m from a bird nest site). Please note that missing values indicate that the aforementioned transect data for large insects were only conducted in the final three years of the study (2015 - 2017, transect, OffsetT). Large insects were not caught in traps, and thus protocol was adjusted. There are also 4 n/a values in the Proportion of Dead vegetation variable in the RMARK data RMarkOS and 1 value in the RMarkWE due to protocol error (it was forgotten for that day). Other variables are complete. Within the same file: RMarkWE, there are 18 n/a values in the DtoEdge column (Distance to Edge) because there was no (obvious) edge to measure from. This did not seem to be a highly relevant variable and thus did not affect conclusions.
Files and variables
File: insect.csv
Description:
Variables
- date:Classic date
- year: as described 20XX
- jdate: Julian Date (day is given a number where Jan 1 = 1)
- avelength: length of insect measured by ruler and presented in mm, calculated mean
- rogers: estimate of size based on the equations from Rogers et al. 1977
- weight: per insect
- number: number of insects per day total, including all traps
- biomass: total calculated biomass for that day (weight x number per day)
- temp:C
- PropDipt:proportion of the catch that day that was Diptera (flies)
- PropLepid:proportion of the catch that day that was Lepidoptera (butterflies and moths)
- PropHymen:proportion of the catch that day that was Hymenoptera (bees and relatives)
- Number:just record number
- osflscore:bird nesting score for the OSFL
- wewpscore:bird nesting score for the WEWP
- trapdays:number of days the trap was open
- traploc:location of insect trap
- transect:raw count of large insects counted on transects (please see note above regarding missing values)
File: RMarkOS.csv
Description:
Variables
- Territory:Bird identification
- FirstFound:Date of found nest, where the first day of the season = 1 (May 1 = 1)
- LastPresent:Last found alive
- LastChecked:Last checked
- Fate:success or not, where success is 0, unsuccessful is 1
- Freq:
- Attempt:1st or 2nd
- Offset:time difference between this nesting event and the insect peak.
- offsetT:offset, in days, from the date of insect peak from Transects (please see note above regarding missing values)
- Slope:% slope
- DtoWater: Distance to water in meters
- AgeFound: Found first day or not, usually first day or second.
- AgeDay1:Usually this is the same as 1, but just in case the nest age was very unclear when the nest was found, this could be a 1 or 2, but usually a 1.
- PropDead:Proportion of dead standing trees
- Year: 20XX
- Species: OSFL or WEWP
- Tempmay:Average May temperature in C.
- daysbelow1:Number of days in May where the temperature dropped below 1 degree C.
- startdate:Date of nest start, in ordinal days (or Julian days, same thing)
- Hot:Number of days in May where the temperature reached equal to or above 17.5 C.
File: RMarkWE.csv
Description:
Variables
- Territory:Bird Identification
- FirstFound:Date nest found to be alive
- LastPresent:Last date nest found to be alive
- LastChecked:Checked Last time
- Fate:success or not, where success is 0, unsuccessful is 1
- Freq:all are 1's
- Attempt:1st or 2nd
- Offset:days offset (timing difference) between the insect peak and the breeding peak (day 9 or 10 in age of chicks in the nest)
- offsetT:days offset (timing difference) between the insect peak from the transect data to the nesting score peak. (please see note above regarding missing values)
- DtoWater:Distance to water (m)
- DtoEdge:Distance to edge (m)
- AgeFound:found on day 1 or not? (usually yes)
- AgeDay1:Always a 1, just ignore.
- PropDead:proportion of standing dead trees.
- Year:
- Species:
- daysbelow1:Number of days in May where the temperature dropped below 1 degree C.
- startdate:Date of nest start, in ordinal days (or Julian days, same thing)
- Hot:Number of days in May where the temperature reached equal to or above 17.5 C.
File: individualoffsets.csv
Description:
Variables
- Year: 20XX
- Bird:territory identifier
- Species:OSFL "O" or WEWP "W"
- Bpeak:date of nesting peak in days
- Ipeak:date of insect peak in days
- offset:days different
- Success:yes (1) or no (0)
- Clutch:number of chicks that made it to the day that at least one fledged.
- Toffset:days of difference (please see note above regarding missing values)
Code/software
Excel will open all data files, and Excel and R are needed for these analyses, such as RMark or MARK for daily nest survival. the Generalized Additive Mixed Models can be completed by various statistical packages and software, although I used RStudio.