Retirement investment theory explains patterns in songbird nest-site choice

When opposing evolutionary selection pressures act on a behavioural trait, the result is often stabilizing selection for an intermediate optimal phenotype, with deviations from the predicted optimum attributed to tracking a moving target, development of behavioural syndromes or shifts in riskiness over an individual's lifetime. We investigated nest-site choice by female golden-winged warblers, and the selection pressures acting on that choice by two fitness components, nest success and fledgling survival. We observed strong and consistent opposing selection pressures on nest-site choice for maximizing these two fitness components, and an abrupt, within-season switch in the fitness component birds prioritize via nest-site choice, dependent on the time remaining for additional nesting attempts. We found that females consistently deviated from the predicted optimal behaviour when choosing nest sites because they can make multiple attempts at one fitness component, nest success, but only one attempt at the subsequent component, fledgling survival. Our results demonstrate a unique natural strategy for balancing opposing selection pressures to maximize total fitness. This time-dependent switch from high to low risk tolerance in nest-site choice maximizes songbird fitness in the same way a well-timed switch in human investor risk tolerance can maximize one's nest egg at retirement. Our results also provide strong evidence for the adaptive nature of songbird nest-site choice, which we suggest has been elusive primarily due to a lack of consideration for fledgling survival.

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Experimental analysis of nest-site choice and its relationship to nest success in an open-cup–nesting passerine

The Auk ◽

10.1642/auk-13-251.1 ◽

2014 ◽

Vol 131 (4) ◽

pp. 539-548 ◽

Cited By ~ 5

Author(s):

Sarah Cancellieri ◽

Michael T. Murphy

Keyword(s):

Experimental Analysis ◽

Nest Site ◽

Nest Success ◽

Nest Site Choice

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Rusty Blackbird Habitat Selection and Survivorship during Nesting and Post-Fledging

Diversity ◽

10.3390/d12060221 ◽

2020 ◽

Vol 12 (6) ◽

pp. 221 ◽

Cited By ~ 1

Author(s):

Patricia J. Wohner ◽

Carol R. Foss ◽

Robert J. Cooper

Keyword(s):

Habitat Selection ◽

Nest Site ◽

Nest Success ◽

Survival Rates ◽

Nest Site Selection ◽

Nest Sites ◽

Fledgling Survival ◽

Euphagus Carolinus ◽

Rusty Blackbird ◽

Habitat Variables

Rusty blackbird (Euphagus carolinus) populations have declined dramatically since the 1970s and the cause of decline is still unclear. As is the case for many passerines, most research on rusty blackbirds occurs during the nesting period. Nest success is relatively high in most of the rusty blackbird’s range, but survival during the post-fledging period, when fledgling songbirds are particularly vulnerable, has not been studied. We assessed fledgling and adult survivorship and nest success in northern New Hampshire from May to August in 2010 to 2012. We also assessed fledgling and adult post-fledging habitat selection and nest-site selection. The likelihood of rusty blackbirds nesting in a given area increased with an increasing proportion of softwood/mixed-wood sapling stands and decreasing distances to first to sixth order streams. Wetlands were not selected for nest sites, but both adults and fledglings selected wetlands for post-fledging habitat. Fledglings and adults selected similar habitat post-fledging, but fledglings were much more likely to be found in habitat with an increasing proportion of softwood/mixed-wood sapling stands and were more likely to be closer to streams than adults. No habitat variables selected during nesting or post-fledging influenced daily survival rates, which were relatively low for adults over the 60-day study periods (males 0.996, females 0.998). Fledgling survival rates (0.89) were much higher than reported for species of similar size.

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The importance of illumination in nest site choice and nest characteristics of cavity nesting birds

Scientific Reports ◽

10.1038/s41598-017-01430-y ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 6

Author(s):

Paweł Podkowa ◽

Adrian Surmacki

Keyword(s):

Nest Site ◽

Cavity Nesting ◽

Nest Site Choice

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Interspecific information on predation risk affects nest site choice in a passerine bird

BMC Evolutionary Biology ◽

10.1186/s12862-018-1301-3 ◽

2018 ◽

Vol 18 (1) ◽

Cited By ~ 4

Author(s):

Jere Tolvanen ◽

Janne-Tuomas Seppänen ◽

Mikko Mönkkönen ◽

Robert L. Thomson ◽

Hannu Ylönen ◽

...

Keyword(s):

Predation Risk ◽

Nest Site ◽

Passerine Bird ◽

Nest Site Choice

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Greater Sage-Grouse nest bowls buffer microclimate in a post-megafire landscape although effects on nest survival are marginal

The Condor ◽

10.1093/ornithapp/duaa068 ◽

2021 ◽

Vol 123 (1) ◽

Cited By ~ 1

Author(s):

Christopher R Anthony ◽

Christian A Hagen ◽

Katie M Dugger ◽

R Dwayne Elmore

Keyword(s):

Site Selection ◽

Nest Site ◽

Spatial Scales ◽

Nest Success ◽

Nest Survival ◽

Nest Site Selection ◽

Bare Ground ◽

Sage Grouse ◽

Burned Areas ◽

Visual Obstruction

Abstract Temperature at fine spatial scales is an important driver of nest site selection for many avian species during the breeding season and can influence nest success. Sagebrush (Artemisia spp.) communities have areas with high levels of vegetation heterogeneity and high thermal variation; however, fire removes vegetation that provides protection from predators and extreme environmental conditions. To examine the influence of microclimates on Greater Sage-Grouse (Centrocercus urophasianus) nest site selection and nest success in a fire-affected landscape, we measured black bulb temperature (Tbb) and vegetation attributes (e.g., visual obstruction) at 3 spatial scales (i.e. nest bowl, microsite, and landscape) in unburned and burned areas. Nest bowls exhibited greater buffering of Tbb than both nearby microsites and the broader landscape. Notably, nest bowls were warmer in cold temperatures, and cooler in hot temperatures, than nearby microsites and the broader landscape, regardless of burn stage. Nest survival (NS) was higher for nests in unburned areas compared to nests in burned areas (unburned NS = 0.43, 95% confidence interval [CI]: 0.33–0.54; burned NS = 0.24, 95% CI: 0.10–0.46). The amount of bare ground was negatively associated with NS, but effects diminished as the amount of bare ground reached low levels. Shrub height and visual obstruction were positively associated with NS during the entire study period, whereas minimum Tbb had a weaker effect. Our findings demonstrate that thermoregulatory selection by Greater Sage-Grouse at nest sites had marginal effects on their NS. However, given that increases in vegetation structure (e.g., shrub height) provide thermal refuge and increase NS, vegetation remnants or regeneration in a post-fire landscape could be critical to Greater Sage-Grouse nesting ecology.

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