Increasing phenological asynchrony between spring green-up and arrival of migratory birds

Abstract

Consistent with a warming climate, birds are shifting the timing of their migrations, but it remains unclear to what extent these shifts have kept pace with the changing environment. Because bird migration is primarily cued by annually consistent physiological responses to photoperiod, but conditions at their breeding grounds depend on annually variable climate, bird arrival and climate-driven spring events would diverge. We combined satellite and citizen science data to estimate rates of change in phenological interval between spring green-up and migratory arrival for 48 breeding passerine species across North America. Both arrival and green-up changed over time, usually in the same direction (earlier or later). Although birds adjusted their arrival dates, 9 of 48 species did not keep pace with rapidly changing green-up and across all species the interval between arrival and green-up increased by over half a day per year. As green-up became earlier in the east, arrival of eastern breeding species increasingly lagged behind green-up, whereas in the west—where green-up typically became later—birds arrived increasingly earlier relative to green-up. Our results highlight that phenologies of species and trophic levels can shift at different rates, potentially leading to phenological mismatches with negative fitness consequences.

Using occupancy modeling to monitor dates of peak vocal activity for passerines in California

“…As the availability of more data and the ability to model them increases in the future, we believe our current power analysis conclusions are conservative. The consequence of this is that we will likely be able to monitor more species over smaller areas, which will be of critical importance because the effects of climate change are expected to be regionally heterogeneous and disruptive (Stralberg et al 2009, Tingley et al 2012, Mayor et al 2017. For example, we expect that peak dates of vocal activity are more complex than the estimates we provided for our study area.…”

“…Compared to resident populations, migrants, having evolved behavioral adaptations that are suitable to tropical and temperate habitats, may have limited ability to adjust behaviors to rapidly changing temperatures on their temperate breeding grounds (Pulido and Widmer 2005). Furthermore, climate change-induced mismatches between environmental conditions on winter and summer ranges may further constrain the ability of migrants to adjust their breeding phenology (Mayor et al 2017). This inflexibility among migrants is consistent with our observation of reduced variance in peak dates and higher overall detectability of Neotropical migrants compared to other species.…”

“…From a meta-analysis of these types of data, Parmesan (2007) estimated an overall spring advancement of bird phenology of 3.7 days decade À1 across the northern hemisphere, but this rate is an average, not a uniform trend. Mayor et al (2017) provide examples of strong regional variation in phenological shifts. Therefore, regional monitoring of the phenologies of multiple species is warranted.…”

The sensitivity of breeding songbirds to changes in seasonal timing is linked to population change but cannot be directly attributed to the effects of trophic asynchrony on productivity

“…It is perhaps unsurprising that studies predicting a general effect of climate change‐induced asynchrony on population‐level processes have produced conflicting evidence, as there is likely to be considerable variation in the extent of asynchrony between individuals, populations and species. The magnitude of asynchrony observed is likely to depend on many factors, including, but not limited to, spatial variability in spring phenology and peaks in prey abundance; seasonal variation in the rate of warming, should species respond to differently timed cues; habitat seasonality; the strength of seasonality in local prey abundance (sharp versus broad or no peak); the proportion of the population that produces multiple broods; and constraints on the ability of individuals to shift reproductive timing due to events outside of the breeding season (Cresswell & McCleery, ; Visser et al., ; Both et al., , ; Durant, Hjermann, Ottersen, & Stenseth, ; Charmantier et al., ; Møller, ; Burger et al., ; Cole, Long, Zelazowski, Szulkin, & Sheldon, ; Hinks et al., ; Mayor et al., ). While single‐population or single‐species studies make it difficult to generalize the impacts of seasonal asynchrony, a multi‐species, broad‐scale approach can produce a more robust assessment of the broad effects of climate change‐induced asynchrony on avian population dynamics.…”

Informing Canada’s commitment to biodiversity conservation: A science-based framework to help guide protected areas designation through Target 1 and beyond

“…In songbirds, asynchrony between food availability and migration arrival has led to population declines (Mayor et al 2017). Inadequate expansion of range limits in response to climate change has caused compression of species' ranges .…”