Arrival and onset of breeding of three passerine birds in eastern Finland tracks climatic variation and phenology of insects

Abstract

Anthropogenic climate change poses a challenge to the annual cycles of migratory birds. It has become urgent to understand whether migratory birds are able to advance their spring phenology when the climate is warming and whether they are able to adjust these phenological phases to the spring phenology in their breeding areas. In this work, we studied long‐term trends in first arrival and onset of breeding for three passerine birds in eastern Finland; the pied flycatcher Ficedula hypoleuca, the common redstart Phoenicurus phoenicurus and the great tit Parus major. The pied flycatcher and the common redstart are long‐distance migrants while the great tit is a partial migrant in Finland. We asked what environmental variables best explain the first arrival or onset of breeding, if there is evidence of ‘thermal delay’ (long‐term increase in the accumulated temperatures) at arrival or onset of breeding and if the interannual variation in the onset of breeding correlates with variation in spring phenology of local insects. We found that the pied flycatcher and the common redstart had advanced their first arrival (explained by increased temperatures at the migration route), but we found no long‐term change in the onset of breeding (explained by local temperatures). Also, the onset of breeding of the great tit is tracking local temperatures. We found no or only weak evidence of thermal delay at arrival or onset of breeding for any of the species. The onsets of breeding for the pied flycatcher and the great tit are also closely tracking the spring phenology of the local insects. The stable or increasing population sizes of all three species in Finland could be a result from their ability to effectively track climatic and environmental variation.

Climate change leads to differential shifts in the timing of annual cycle stages in a migratory bird

“…If the dates when birds are born affect both their arrival and moult, we should also observe an advancement in arrival dates, but it was not the case in our study population. Other migratory species, however, have been reported to advance their arrival dates (Usui, Butchart, & Phillimore, ) and also other populations of pied flycatcher (Ahola et al., ; Both et al., ; Valtonen et al., ). Arrival dates, in comparison to the onset of moult, are much more susceptible to modulations by environmental conditions, such as weather, body condition and wind patterns (Ahola et al., ; Bauer, Gienapp, & Madsen, ; Both et al., ; Eikenaar & Schmaljohann, ; Erni, Liechti, & Bruderer, ; Sinelschikova, Kosarev, Panov, & Baushev, ; Teitelbaum et al., ).…”

“…Climate change unequally affects the annual cycle stages of bird (Eichhorn et al., ; Valtonen et al., ; Van der Jeugd et al., ) and mammal species (Moyes et al., ; Ozgul et al., ). Such shifts may lead to positive fitness consequences in some cases, for example, in marmots' offspring that now have more time.…”

“…Finally, long-term data on date of arrival and breeding of migratory birds suggest that timing of breeding and migration may not respond the same way to climate change. There are reports of both shorter (Both & Visser, 2001) and longer (Ahola et al, 2004;Valtonen, Latja, Leinonen, & P€ oys€ a, 2016) intervals between arrival and breeding. Thus, for animals with more complex annual cycles, the assessment of the impacts of climate change becomes considerably more challenging, because unequal changes in the timing of stages may impose fitness costs (e.g.…”

Timing avian long-distance migration: from internal clock mechanisms to global flights

“…Thus, in this population, the interval between arrival and breeding became progressively shorter, and further advancement of laying dates would be constrained by the lack of advancement in arrival dates 80 . Curiously, this pattern can be very different in other populations; for example, in a Finnish population of pied flycatchers, the observed pattern was the opposite: 9 while arrival dates advanced, the timing of breeding did not, causing an increase in the time between arrival and breeding 87,88 . Still, both cases suggest that timing of migration and breeding do not respond similarly to climate change.…”

Use of field‐portable ultrasonography reveals differences in developmental phenology and maternal egg provisioning in two sympatric viviparous snakes

“…Recently, there has been increasing interest in the dynamics of development in the wild, particularly with rising concern regarding effects of climate change on reproductive phenology (Abouheif et al, 2014;Gilbert, Bosch, & Ledón-Rettig, 2015;Ledón-Rettig & Pfennig, 2011;Parmesan, 2007;Sultan, 2007;Telemeco, Elphick, & Shine, 2009;Walther et al, 2002;Winkler, Dunn, & McCulloch, 2002). Shifts in the onset of breedings seasons, length of developmental periods, and hatching times have been documented in a wide range of species, including insects, amphibians, turtles, lizards, and birds (e.g., Edge et al, 2017;Parmesan, 2007;Rutschmann et al, 2016;Urban, Richardson, & Freidenfelds, 2014;Valtonen, Latja, Leinonen, & Pöysä, 2017). Yet much remains to be learned regarding plasticity and phylogenetic constraints on developmental life history in natural populations with varying reproductive modes, including viviparity (live-bearing) and oviparity (eggbearing) species (Sultan, 2007).…”