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Table 2 Explanatory variables tested for effects on demographic rates of Arctic-breeding shorebirds

From: Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds

Explanatory variable

Type of variable

Response

Nest success

Partial hatching of clutches

Return rate

Breeding movements

Change in body mass

Geolocator

Fixed (binomial)

X

X

X

X

X

Sex

Fixed (categorical)

X

Nest successa

Fixed (categorical)

X

Previously markedb

Fixed (binomial)

X

Body mass

Fixed (continuous)

X

Capture date

Fixed (continuous)

X

Blood sample

Fixed (binomial)

X

Marker massc

Fixed (continuous)

X

Difference between capture and recapture date

Fixed (continuous)

X

Difference between capture and recapture nest age

Fixed (continuous)

X

Site

Random on intercept and slope of geolocator effect

X

X

X

X

X

Year

Random on intercept

X

X

X

X

X

Individual

Random on intercept

X

Species

Random on intercept

X

X

X

  1. Geolocator was the primary variable of interest, but other variables were included (denoted by “X”) in species-specific GLMMs to control for potential confounding factors and identify subsets of the population that could be targeted to improve recovery rates of geolocators in future field studies.
  2. aFor individuals with multiple nest attempts in 1 year, we used the fate of the final attempt as a potential explanatory variable of return rate
  3. bWhether the current capture record is a recapture of an individual that was previously marked at the capture site
  4. cTotal mass of color markers and metal band applied to each individual, not including the geolocator or attachment