Weather and climate change drive annual variation of reproduction by an aerial insectivore

Abstract

For many bird species, but especially aerial insectivores, reproduction depends on weather. Climate change is likely to intensify effects, but with uncertain consequences. We report 22 years of data on Eastern Kingbird (Tyrannus tyrannus) reproduction for two populations located in different hygric environments undergoing climate change; mesic central New York, USA, (NY; 12 years) and xeric southeastern Oregon, USA, (OR: 10 years). Laying date became earlier with increasing temperature in the 30-day period preceding laying in identical fashion at both sites, and in years of early laying, clutch size was larger, length of laying season increased, and failed initial nesting attempts were more often replaced. High temperature in the 10-days preceding mean laying date was associated with shorter laying seasons, while a site by 10-day temperature interaction reflected an increase and decrease of clutch size with increasing 10-day temperature in NY and OR, respectively. Seasonal rate of clutch size decline was higher when the laying season was short but also slowed in xeric OR when rain was abundant in the 10-days prior to mean laying date. Nest predation drove annual variation in young fledged/nest, but the latter also increased and decreased with increasing maximum temperature during the nestling phase in mesic NY and xeric OR, respectively. Potential effects of climate change on kingbird populations are thus high given the dependence of reproduction on weather, and climate change likely contributed to declines of kingbirds in OR. Declines of kingbirds in NY appear unrelated to warming climates because higher temperatures advanced laying dates and yielded greater nest productivity. However, length of laying season declined across years at both sites, and thus early season gains may be negated by poor conditions late in the season that may be causing shorter laying seasons. Further work is needed to identify causes for the latter changes.Les conditions météorologiques et les changements climatiques entraînent la variation annuelle de la reproduction d'un insectivore aérien responsables des saisons de ponte plus courtes. Des travaux supplémentaires sont nécessaires à ce sujet pour qu'on puisse identifier les causes.

First egg dates of Tree Swallows ( Tachycineta bicolor ) nesting in boxes in west Michigan advanced with increasing spring temperatures between 1993 and 2018

“…Many bird species have advanced their egg-laying dates in response to increasing spring temperatures and milder winters (Crick et al 1997, Sanz 2002, Both et al 2004, Visser et al 2009. For example, in North America, Eastern Kingbirds (Tyrannus tyrannus; (Murphy et al 2022), Tree Swallows (Tachycineta bicolor; Dunn and Winkler 1999, Rioux Paquette et al 2014, Bourret et al 2015, Irons et al 2017, Shipley et al 2020, Eastern Bluebirds (Sialia sialis; Torti and Dunn 2005), Blackthroated Blue Warblers (Setophaga caerulescens; Townsend et al 2013), and Red-winged Blackbirds (Agelaius phoeniceus; Torti and Dunn 2005), amongst other species have begun laying earlier in warmer springs (Dunn and Winkler 2010). However, midwinter temperatures may be more important in some species.…”

Atmospheric pressure predicts probability of departure for migratory songbirds

“…Weather is a ubiquitous factor in the daily lives of animals, and it can have both immediate and long-term impacts on reproduction [ 1 – 3 ] and survival [ 4 – 6 ]. To appropriately respond to weather conditions, animals have evolved a diverse array of behavioral adaptions [reviewed by 7 ].…”