Data from: Context-dependent costs and benefits of a heterospecific nesting association

The costs and benefits of interactions among species can vary spatially or
temporally, making them context-dependent. For example, benefits
associated with nesting near species that deter predators may give way to
costs if the association increases the risk of predation during other
stages of reproduction. We examined the extent to which the costs and
benefits of heterospecific aggregations between a declining shorebird, the
Hudsonian Godwit (Limosa haemastica), and a potential protector and
predator, the Mew Gull (Larus canus), varied with breeding stage.
Specifically, we assessed the spatial distribution and fate of 43 godwit
and 262 gull nests in Beluga, Alaska, from 2014 – 2016. We then evaluated
the effect of habitat and proximity to gulls on daily survival rates of
120 godwit nests from 2009 – 2016. We also examined the relationship
between the proximity to gulls and survival of godwit chicks to five days
old, the period when they are vulnerable to gull predation. Nests of
godwits and gulls were significantly clustered across the landscape, a
pattern that habitat heterogeneity failed to explain. Hatching success of
godwit nests improved with proximity to the gull colony and increasing
numbers of gull nests within 200m. In contrast, survival of godwit chicks
to five days improved with increasing distance to the gull colony. The
costs and benefits that godwits derived from associating with Mew Gulls
were thus context-dependent, with benefits pre-hatch and costs post-hatch.
Our results show how spatiotemporal variation in species interactions
preclude simple generalizations about the nature of their outcomes.