DOI: 10.5061/dryad.x95x69pfq
title: Data from: Behavioral adjustments in the social associations of a precocial shorebird mediate the costs and benefits of grouping decisions

description: Animals weigh multiple costs and benefits when making grouping decisions.
 The cost-avoidance grouping framework proposes that group density,
 information quality, and risk affect an individual’s preference for con-
 or heterospecific groups. However, this assumes the cost-benefit balance
 of a particular grouping is constant spatiotemporally, which may not
 always be true. Investigating how spatiotemporal context influences
 grouping choices is therefore key to understanding how animals contend
 with changing conditions.  Changes in body size during
 development lead to variable conditions for individuals over short
 timescales that can influence their ecological interactions. Hudsonian
 godwits (Limosa haemastica), for instance, form a protective nesting
 association with a major predator of young godwit chicks, colonial
 short-billed gulls (Larus brachyrhynchus). Godwit broods may avoid areas
 of higher gull densities when chicks are susceptible to gull predation but
 likely experience higher risk from alternative predators as a result.
 Associating with conspecifics could allow godwits to buffer these costs
 but requires enough other broods with whom to group.  To
 determine how age-dependent predation risk and conspecific density
 influence godwit grouping behaviors, we first quantified the
 time-dependent effects of con- and heterospecific interactions on the
 mortality risk for godwit chicks throughout development. We then
 determined how godwit density and chick age affected their associations
 with con- and heterospecifics.  We found that younger godwit
 chicks’ survival improved with closer association with conspecifics,
 earlier hatch dates, and lower gull densities, whereas older chicks
 survived better with earlier hatch dates, though this effect was less
 clear. Concomitantly, godwit broods avoided gulls early in development and
 when godwit densities were high but maintained loose associations with
 conspecifics throughout development.  We identified how
 individuals can optimally shift with whom they group according to risks
 that vary spatially and temporally. Investigating the effects of a
 species’ ecological interactions across spatiotemporal contexts in this
 way can shed light on how animals adjust their associations according to
 the costs and benefits of each association.
description: We located all Hudsonian godwit (<em>Limosa
 haemastica</em>) and short-billed gull
 (<em>Larus brachyrhynchus</em>) nests<em> </em>in
 two plots near Beluga River, AK from 2009 to 2019. We followed nests to
 hatch and captured 1-2 chicks per brood to be continuously monitored by
 VHF telemetry. We resighted chicks to confirm survival every 2-3 days.
 Mortality was confirmed by carcass recovery or if a chick was not found
 for 3 consecutive attempts. We recaptured chicks weekly to monitor the
 attachment media of the radio and collect morphometric data.
  
description: Program R v.4.1.0 was used for all analyses.
 Use the ReadMe.txt file to work with data.