Time of emergence of novel climates for North American migratory bird populations

Abstract

To better understand the ecological implications of global climate change for species that display geographically and seasonally dynamic life‐history strategies, we need to determine where and when novel climates are projected to first emerge. Here, we use a multivariate approach to estimate time of emergence (ToE) of novel climates based on three climate variables (precipitation, minimum and maximum temperature) at a weekly temporal resolution within the Western Hemisphere over a 280‐yr period (2021–2300) under a high emissions scenario (RCP8.5). We intersect ToE estimates with weekly estimates of relative abundance for 77 passerine bird species that migrate between temperate breeding grounds in North America and southern tropical and subtropical wintering grounds using observations from the eBird citizen‐science database. During the non‐breeding season, migrants that winter within the tropics are projected to encounter novel climates during the second half of this century. Migrants that winter in the subtropics are projected to encounter novel climates during the first half of the next century. During the beginning of the breeding season, migrants on their temperate breeding grounds are projected to encounter novel climates during the first half of the next century. During the end of the breeding season, migrants are projected to encounter novel climates during the second half of this century. Thus, novel climates will first emerge ca 40–50 yr earlier during the second half of the breeding season. These results emphasize the large seasonal and spatial variation in the formation of novel climates, and the pronounced challenges migratory birds are likely to encounter during this century, especially on their tropical wintering grounds and during the transition from breeding to migration. When assessing the ecological implications of climate change, our findings emphasize the value of applying a full annual cycle perspective using standardized metrics that promote comparisons across space and time.

North American Birds Require Mitigation and Adaptation to Reduce Vulnerability to Climate Change

“…For species such as these, it is unknown if range gains in new locations will be sufficient for sustaining populations, given the rapid nature of climate change and the time it takes to establish populations. Lastly, novel climates aren't projected to peak in the non-breeding season until the first half of the next century [101], suggesting that more changes are to come beyond the temporal extent of our projections.…”

Causes and consequences of facultative sea crossing in a soaring migrant

“…Our results indicate that migrants are sensitive to the dynamics of their aerial environment and their behaviour and movement properties are strongly affected by local meteorological conditions. Changing atmospheric patterns due to climate change may thus result in changes in migration route selection of migrating white storks, with possible implications for population dynamics (La Sorte, Fink, & Johnston, ) and conservation (Wilcove & Wikelski, ).…”

Climatic conditions during migration affect population size and arrival dates in an Afro‐Palaearctic migrant

“…Studies of other species have found individuals to be highly repeatable in their migration schedule, particularly in their pre-breeding movements (Stanley et al 2012, Conklin et al 2013, and individuals may use weather conditions to inform migratory timing (Both 2010, Schmaljohann et al 2012. Correlations between weather conditions at breeding and wintering sites are likely to provide cues for migratory birds to adjust their migration schedule (Saino & Ambrosini 2008), but their usefulness may be reduced due to the spatial variability of climate change (La Sorte et al 2019). It is most likely that both body condition and the provision of cues influence arrival dates, given that individuals may be repeatable in migration schedule but less so in the route taken, which is presumably dependent on ground conditions (Stanley et al 2012).…”