Nest attentiveness drives nest predation in arctic sandpipers

Abstract

Most birds incubate their eggs to allow embryo development. This behaviour limits the ability of adults to perform other activities. Hence, incubating adults trade off incubation and nest protection with foraging to meet their own needs. Parents can either cooperate to sustain this tradeoff or incubate alone. The main cause of reproductive failure at this reproductive stage is predation and adults reduce this risk by keeping the nest location secret. Arctic sandpipers are interesting biological models to investigate parental care evolution as they may use several parental care strategies. The three main incubation strategies include both parents sharing incubation duties ('biparental'), one parent incubating alone ('uniparental'), or a flexible strategy with both uniparental and biparental incubation within a population ('mixed'). By monitoring the incubation behaviour in 714 nests of seven sandpiper species across 12 arctic sites, we studied the relationship between incubation strategy and nest predation. First, we described how the frequency of incubation recesses (NR), their mean duration (MDR), and the daily total duration of recesses (TDR) vary among strategies. Then, we examined how the

Shorebird Reproductive Response to Exceptionally Early and Late Springs Varies Across Sites in Arctic Alaska

“…Because Arctic-breeding shorebirds are primarily income breeders (Klaassen et al, 2001;Piersma et al, 2003, but see Hobson and Jehl, 2010), changes in the timing and abundance of invertebrates may in turn affect shorebird nest attendance due to adult food limitations (Tulp and Schekkerman, 2006;Reneerkens et al, 2011). Adults leaving nests unattended or making more trips away from the nest may increase the likelihood of predation by reducing crypsis of the eggs (adults are better camouflaged than eggs themselves) or drawing attention to the nest (activity near a nest can reveal its location, Smith et al, 2007Smith et al, , 2012Reneerkens et al, 2011;Bulla et al, 2016;Meyer et al, 2020). But evidence linking warm springs with increased nesting success is equivocal; Weiser et al (2018a) found limited evidence for such a relationship, with only two of 14 species investigated across a broad geographic region of the Arctic having higher nest survival in warm springs.…”

Behavioural responses of breeding arctic sandpipers to ground-surface temperature and primary productivity

“…This circumpolar network of study sites (the "Interactions Working Group")offersalargediversity of productivity and temperature conditions within the Arctic biome ( Fig. S1; Meyer et al, 2020).…”

“…Nests were found systematically by rope-dragging or opportunistically by walking through suitable breeding habitat, flushing incubating birds and/or following them visually as they walk back to their nest. Between one and three Calidris species were monitored at each site (Table S1; see distribution of species and location of study sites on figure 1 in Meyer et al, 2020).…”

“…Starting and ending times of recesses were documented using a previously used temperature threshold value (i.e. the median incubation temperature calculated over 24 h periods minus 3°C; Bulla et al, 2014;Meyer et al, 2020;Moreau et al, 2018), with a recess beginning when the measured temperature dropped below the threshold temperature and ending when reaching it again (and figure 1 in Moreau et al, 2018; see also Tulp and Schekkerman, 2006).…”

“…Hence, both strategies may result in intermittent incubation with detectable recesses, but incubation patterns (e.g. number and duration of recesses) greatly vary between strategies (Meyer et al, 2020;Norton, 1972;Reneerkens et al, 2011;Smith et al, 2012b).…”