Information collected during the post-breeding season guides future breeding decisions in a migratory bird

Jere Tolvanen,Chiara Morosinotto,Jukka T Forsman,Robert L Thomson

doi:10.1007/s00442-020-04629-5

Abstract

Breeding habitat choice and investment decisions are key contributors to fitness in animals. Density of individuals is a well-known cue of habitat quality used for future breeding decisions, but accuracy of density cues decreases as individuals disperse from breeding sites. Used nests remain an available information source also after breeding season, but whether such information is used for breeding decisions is less well known. We experimentally investigated whether migratory, cavity-nesting pied flycatchers (Ficedula hypoleuca) prospect potential breeding sites after breeding season and use old nests as a cue for future breeding decisions. In late summer 2013, forest sites were assigned to four treatments: (1) sites including nest boxes with old nests of heterospecifics (tits), (2) sites including suitable but empty nest boxes, (3) sites with unsuitable nest boxes, or (4) sites without any nest boxes. In the following year, we investigated pied flycatcher habitat choice and reproductive investment according to these “past” cues while also controlling for additional information sources present during settlement. Flycatchers preferred sites where tits had been perceived to breed in the previous year, but only if great tits were also currently breeding in the site and had a relatively high number of eggs. Old flycatchers avoided sites previously treated with suitable but empty cavities, whereas young flycatchers preferred sites where tits had apparently bred in the previous year. Also egg mass, but not clutch size or clutch mass, was affected by the combination of past treatment information and current tit abundance.

Highlights

Breeding habitat choice is an important decision for animals by defining available resources and risks for both breeding adults and their progeny
Pied flycatcher settlement behavior was affected by the experimentally simulated habitat quality and nest-site availability information collected during the post-breeding period of the previous year
Timing of breeding and reproductive investment measured as mean egg mass were influenced by the information cues available in the previous post-breeding season

Summary

Introduction

Breeding habitat choice is an important decision for animals by defining available resources and risks for both breeding adults and their progeny. A variety of migratory birds use heterospecific information for habitat choice and investment decisions within a breeding season (Forsman et al 2002; Thomson et al 2003; Hromada et al 2008; Sebastián-Gonzáles et al 2010; Parejo et al 2012; Loukola et al 2013; Kivelä et al 2014; Szymkowiak et al 2017; Tolvanen et al 2018). Whether heterospecific cues are assessed during or after a breeding season to aid habitat choice in future breeding attempts is, less well known (Parejo et al 2005; Sebastián-Gonzáles et al 2010; Forsman et al 2014; Kivelä et al 2014)

Methods

Results

Conclusion