Shifting Breeding Phenology in Eurasian Kestrels Falco tinnunculus: Effects of Weather and Urbanization

Abstract

Human-induced climate change and the destruction of natural habitats are two of the main threats to biodiversity worldwide. Animals can use local weather conditions as environmental cues for optimal breeding conditions, but climate change can cause severe phenological mismatches. Migratory species that have a shorter time period for their settlement decision, or species that breed in heavily transformed habitats, might be specifically sensitive to such change. Here, we analyzed the arrival and egg-laying dates of Eurasian kestrels (Falco tinnunculus) in Vienna (415 km 2 ), Austria, gathered by academic and citizen scientists between 2010 and 2018. To identify critical time windows in which weather variables affect phenology, we used a sliding window approach and considered the degree of urbanization as an additional predictor to unravel habitat-dependent relationships. Furthermore, we assessed the relationship between arrival and egg-laying (i.e., the length of the time gap in-between). We found that arrival dates were not influenced by urbanization, and that egg-laying started earlier in drier weather conditions prior to arrival, and earlier in more natural areas than in the urban center. The time gap between arrival and egg-laying was slightly shorter in breeding pairs that arrived later at their nest sites. Our results might indicate a strategy to mitigate later arrival by relatively earlier egg-laying through reducing the length of the courtship period. Such a behavioral adaptation could avoid negative effects of a later onset of breeding on their reproductive success, which is known from previous studies in our urban population.

Declines in Common and Migratory Breeding Landbird Species in South Korea Over the Past Two Decades

“…Thus, we speculate that these species have potential to colonize vacant habitat as the climate changes. Eurasian Kestrels in Northern Europe have expanded their range and had greater breeding success as spring temperature have increased (Elmhagen et al, 2015;Huchler et al, 2020). Gray Starlings and Eurasian Hoopoe forage on the ground (Joo et al, 2016;Plard et al, 2020), and warmer temperatures and increased precipitation could lead to increased prey availability in agricultural landscapes (Arlettaz et al, 2010;Plard et al, 2020).…”

Breeding Phenology of Red-Shouldered Hawks (Buteo lineatus) Is Related to Snow Cover and Air Temperature During the Pre-Laying Period

“…Warmer spring temperatures have been associated with earlier breeding in many raptor species, including Northern Goshawks (Accipiter gentilis) in Finland (Lehikoinen et al, 2013) and Idaho/Utah, United States (Bangerter et al, 2021), Peregrine Falcons (Falco peregrinus) in South Africa (Sumasgutner et al, 2020), Eurasian Kestrels (Falco tinnunculus) in Vienna (Kreiderits et al, 2016), and Common Buzzards (Buteo buteo) in Finland (Lehikoinen et al, 2009), among others (Nielsen and Møller, 2006;Dunn, 2019). Delayed egg-laying of Eurasian Kestrels is associated with more rain in the winter/early spring pre-laying period (Huchler et al, 2020) or in the spring (Constantini et al, 2010;Kreiderits et al, 2016). Delayed egg-laying of Rough-legged Hawks (Buteo lagopus; Terraube et al, 2015), Tengmalm's Owls (Aegolius funereus; Kouba et al, 2020), Tawny Owls (Strix aluco; Solenen, 2014), and Ural Owls (Strix uralensis; Lehikoinen et al, 2011) is linked to increased winter/spring snow cover, which reduces the prey availability of some species of voles.…”

“…Based on prior studies (Huchler et al, 2020), we considered that the weather in the period 3.5-5 weeks prior to egglaying was most likely to influence laying date (and thus, hatching date, as the length of the incubation period likely did not vary greatly). Because Red-shouldered Hawk courtship in our study area generally begins in February, with egglaying in mid-to late March, we considered that the weather conditions in March and February were the most likely to be biologically meaningful.…”

Effect of urbanization and its environmental stressors on the intraspecific variation of flight functional traits in two bumblebee species

“…Widespread phenomena, such as the progressive expansion of agricultural and urban lands are driving deep changes on ecosystems, often by driving intraspecific phenotypic variation (Alberti et al, 2017; Nooten & Rehan, 2020). Plants and animals respond to these marked environmental variations by shifting their distribution (Colla et al, 2012) and phenology (Huchler et al, 2020), and/or shaping some morphological traits considered “functional”, i.e. relevant for their ecology, fitness and behaviour (Alberti et al, 2017; Eggenberger et al, 2019).…”

“…Widespread phenomena, such as the progressive expansion of agricultural and urban lands are driving deep changes on ecosystems, among which the replacement of natural areas and the creation of novel ecosystem conditions Plants and animals respond to these marked environmental variations by shifting their distribution (Colla et al, 2012) and phenology (Huchler et al, 2020), and/or shaping some morphological traits considered "functional", i.e., relevant for their ecology, fitness and behaviour (Alberti et al, 2017;Eggenberger et al, 2019;Nooten & Rehan, 2020). Trait variation due to environmental alteration is particularly relevant in those organisms responsible for ecosystem services, such as pollinators, since changes in their traits could jeopardize the service provided (Buchholz & Egerer, 2020).…”