A call for full annual cycle research in animal ecology

Abstract

For vertebrates, annual cycles are organized into a series of breeding and non-breeding periods that vary in duration and location but are inextricably linked biologically. Here, we show that our understanding of the fundamental ecology of four vertebrate classes has been limited by a severe breeding season research bias and that studies of individual and population-level responses to natural and anthropogenic change would benefit from a full annual cycle perspective. Recent emergence of new analytical and technological tools for studying individual and population-level animal movement could help reverse this bias. To improve understanding of species biology and reverse the population declines of many vertebrate species, a concerted effort to move beyond single season research is vital.

Virginia and Yellow Rail autumn migration ecology: synthesis using multiple data sets

“…We found Yellow Rails in shallow flooded stands of annual moist soil plants, which may differ from previous work since perennial moist soil plants were less abundant within the wetlands we surveyed (which were dominated to 27 October, median September 23 [4]), and Virginia Rails were less abundant during concurrent surveys (~8000 Sora and 97 Virginia Rails; [4]). These differences in abundance led us to speculate as to the effectiveness of our survey method at detecting Virginia Rails.…”

“…The Virginia Rail model fit the data (χ 2 = 7.336, df = 8, p = 0.50) as did the Yellow Rail model (χ 2 = 11.2, df = 8, p = 0.19). which is shorter than Sora [4]. We observed many fewer individual Yellow Rails than Sora, though again the lack of formal population estimates limits our comparisons of these counts.…”

“…Understanding species' habitat selection during autumn migration is vital to understanding how migration impacts demography [4,31]. Future work in this area should consider the landscape around each wetland, and the degree of wetland isolation on the landscape, as these have been found to be important during the breeding season for rails and during migration for shorebirds [32][33].…”

“…ATVs were driven along transects, as described in [18] and whenever a rail was observed, either flushing out of the vegetation or on the ground, a point was taken where the bird was first detected. While this method detected thousands of Sora over the five-year project [4], we detected far fewer Virginia and Yellow Rails.…”

“…To conserve migratory species, threats and pressures that operate in all parts of their annual cycle must be studied, including those that may limit the habitats the species use during migration, and consequently affect survival [3][4]. Studying species that have low detection rates, such as rails, which are among the least studied birds in North America, can be especially difficult [5][6].…”