Fledgling Sex Ratio Is Determined by Egg Loss, Hatching Order, Nestling Mortality, and Inter-Annual Food Fluctuations for Boreal Owls, Aegolius funereus

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389030%3A_____%2F25%3A00618537" target="_blank" >RIV/61389030:_____/25:00618537 - isvavai.cz</a>

Alternative codes found

RIV/60460709:41330/25:102018

Result on the web

<a href="https://doi.org/10.1002/ece3.71001" target="_blank" >https://doi.org/10.1002/ece3.71001</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/ece3.71001" target="_blank" >10.1002/ece3.71001</a>

Result language

angličtina

Original language name

Fledgling Sex Ratio Is Determined by Egg Loss, Hatching Order, Nestling Mortality, and Inter-Annual Food Fluctuations for Boreal Owls, Aegolius funereus

Original language description

Extensive research has been conducted to explore adaptive variation in offspring sex ratios, focusing on birds as a model group. However, studies to date have not been comprehensive in scope, limiting our understanding of whether there is substantial within- or among-year variation in offspring sex ratios, which environmental conditions and mechanisms are associated with this variation, and when during a nesting attempt the fledgling sex ratio is largely determined. To address these gaps, we analyzed our 18-year dataset from 542 sexually size-dimorphic Boreal Owl (Aegolius funereus) offspring in 140 nests. At hatching, within-nest variation in hatching order emerged as the primary predictor of sex ratio, with later-hatched offspring more likely to be female in larger broods when one or more eggs failed to hatch, such broods were primarily produced in years of abundant food. No evidence of direct sex-dependent mortality among nestlings was observed between hatching and fledging, instead, sex-independent mortality of nestlings increased for offspring that hatched later in a brood and during years of low Apodemus and Microtus prey abundance. At fledging, the primary predictor of offspring sex ratio was year-to-year variation in food abundance, with more male fledglings produced in years of abundant food and larger broods, but only in nests where one or more nestlings had died. We found no compelling evidence for within-season variation in offspring sex ratio between early- and late-season nests. Our findings suggest that offspring sex ratios in raptors are shaped by a complex interplay of maternal adjustments and environmental influences, particularly food abundance, which drives changes in brood size. These findings emphasize the need for future research to conduct a more comprehensive examination into offspring sex adjustments, particularly focusing on alterations in sex ratio during multiple nesting stages and their association with variation in offspring mortality and environmental conditions.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10618 - Ecology

Project

<a href="/en/project/GA25-17362S" target="_blank" >GA25-17362S: Small mammals as key indicators of sublethal impacts of air pollution and metal(loid) deposition in terrestrial ecosystems</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Ecology and Evolution

ISSN

2045-7758

e-ISSN

2045-7758

Volume of the periodical

15

Issue of the periodical within the volume

3

Country of publishing house

US - UNITED STATES

Number of pages

20

Pages from-to

e71001

UT code for WoS article

001444325500001

EID of the result in the Scopus database

2-s2.0-105000423141