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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