Data from: A call in the dark: Nocturnal flight calls and their potential to advance the study of avian migration

Migratory birds have experienced widespread declines in abundance and face
numerous threats. The conservation of migratory species relies in part on
an improved knowledge of active migration behavior, but this behavior is
difficult to study as most birds migrate at night. Flight calls, which are
species-specific calls produced by many nocturnal migrants during flight,
offer an opportunity to improve our understanding of migration behavior
and serve as a tool to monitor populations. Although nocturnal flight call
monitoring has been historically limited to small spatial and temporal
scales, recent technological advancements have allowed researchers to
largely shed these constraints. Despite this expansion, there are many
unanswered questions regarding the function of flight calls and the
proximate drivers of calling behavior. There are also unaddressed concerns
that the methods used to record nocturnal flight calls, as well as other
organismal, environmental, and social factors, may bias data in ways that
impede (or prohibit) comparisons across time and space. Research that
addresses these limitations and potential sources of bias will advance the
use of nocturnal flight call monitoring for migratory bird
research.