Data from: Migratory singers dynamically overlap the signal space of a breeding warbler community

Migratory species inhabit many communities along their migratory routes.
Across taxa, these species repeatedly move into and out of communities,
interacting with each other and locally breeding species and competing for
resources and niche space. However, their influence is rarely considered
in analyses of ecological processes within the communities they
temporarily occupy. Here, we explore the impact of migratory species on a
breeding community using the framework of acoustic signal space, a limited
resource in which sounds of species within communities co-exist. Migrating
New World warblers (Parulidae, hereafter referred to as migrant species)
often sing during refueling stops in areas and at times during which
locally breeding warbler species (hereafter breeding species) are singing
to establish territories and attract mates. We used eBird data to
determine co-occurrence of 19 migrant and 11 breeding warbler species
across spring migration in SW Michigan, generated a signal space from song
recordings of these species, and examined patterns of signaling overlap
experienced by breeding species as migrants moved through the community.
Migrant species were present for two-thirds of the breeding season of
local species, including periods when breeding species established
territories and attracted mates. Signaling niche overlap experienced by
individual breeding species was idiosyncratic and varied over time, yet
niche overlap between migrant and breeding species occurred more commonly
than between breeding species or between migrant species. Nevertheless,
the proportion of niche overlap between migrant and breeding warblers was
similar to overlap among breeding species. Our findings showed that
singing by migrant species overlapped the signals of many breeding
species, suggesting that migrants could have unexplored impacts on
communication in breeding species, potentially affecting song detection
and song evolution. Our study contributes to a growing body of research
documenting impacts of migratory species on communities and ecosystems.