Temperature has a causal effect on avian timing of reproduction

Abstract

Many bird species reproduce earlier in years with high spring temperatures, but little is known about the causal effect of temperature. Temperature may have a direct effect on timing of reproduction but the correlation may also be indirect, for instance via food phenology. As climate change has led to substantial shifts in timing, it is essential to understand this causal relationship to predict future impacts of climate change. We tested the direct effect of temperature on laying dates in great tits (Parus major) using climatized aviaries in a 6-year experiment. We mimicked the temperature patterns from two specific years in which our wild population laid either early ('warm' treatment) or late ('cold' treatment). Laying dates were affected by temperature directly. As the relevant temperature period started three weeks prior to the mean laying date, with a range of just 48C between the warm and the cold treatments, and as the birds were fed ad libitum, it is likely that temperature acted as a cue rather than lifting an energetic constraint on the onset of egg production. We furthermore show a high correlation between the laying dates of individuals reproducing both in aviaries and in the wild, validating investigations of reproduction of wild birds in captivity. Our results demonstrate that temperature has a direct effect on timing of breeding, an important step towards assessing the implication of climate change on seasonal timing.

Diversidade local e influência da sazonalidade sobre taxocenoses de anfíbios e répteis na Reserva Extrativista Chico Mendes, Acre, Brasil

“…Esta relação se deve à dependência dos anfíbios aos ambientes úmidos tanto para manutenção das condições fisiológicas quanto para reprodução (Hatano et al, 2002;Both et al, 2008;Canavero & Arim, 2009;Cole et al, 2014). A maioria das espécies de anfíbios que possuem reprodução explosiva ou restrita a poucos meses do ano sincronizam suas atividades com o período chuvoso , permitindo assim uma maior taxa de sobrevivência e aptidão (Visser et al, 2009). Algumas espécies também podem ser encontradas em maiores abundâncias durante períodos menos chuvosos, outras possuem reprodução prolongada e podem ser encontradas ao longo de todo o ano, principalmente em locais onde o clima não tem sazonalidade marcante (Menin et al, 2008).…”

Phenotypic plasticity and population viability: the importance of environmental predictability

“…Timing traits are good examples of plastic quantitative characters-such as germination timing in annual plants (Freas & Kemp 1983), spawn timing in fish (Genner et al 2010) or laying date in birds (Visser et al 2009)-each of which might be triggered by photoperiod, temperature or some other cue. Mean (absolute) fitness in the population W TOTAL per generation had three components:…”

Social cues are preferred over resource cues for breeding-site selection in Barn Swallows

“…However, there are many buildings available for nest sites in our study area, and since there were more buildings without new nests than buildings with new nests, we think that the breeding-site selection of high-quality males does not influence that of other males. Although the date that females lay the first eggs was assumed as an indicator of breeding-site preference in birds (Forsman et al 2008), it is affected by seasonal climate variables, such as temperature (Visser et al 2009), and male quality (Helfenstein et al 2003). Considering the direct effects of nest-site quality in breeding-site preference, it may be important to use the male arrival date as an indicator of breeding-site preference.…”