Work

Clutch and egg size in marine and freshwater common terns Sterna hirundo

Year: 2025

Type: article

Abstract: Clutch and egg sizes in birds are affected by intrinsic and environmental factors. Clutch size is affected by food availability and predation risk, while egg size is influenced by parental age and environmental conditions during both the breeding and pre-breeding period. In the Common Tern Sterna hirundo , egg size decreases with the laying sequence, and the survival rate of the last-hatching chicks is lower than that of their siblings. We studied the differences in clutch size, egg volume, and egg volume reduction in Common Terns inhabiting marine and freshwater habitats. Clutch size varied in the studied regions. Egg size differed annually, but the greater volume reduction of second- and third-egg was found in marine habitats and among late clutches, regardless of the year. Egg volume and reductions were correlated with females’ body characteristics.

Source: Natura Croatica

DOI: 10.20302/nc.2025.34.26

Authors: Toni Kočevar, Jelena Kralj

Institutions: Znanstveno-raziskovalno središče Koper, Centre européen de recherches en droit des familles, des assurances, des personnes et de la santé, Croatian Academy of Sciences and Arts

Language: English

Topic: Avian ecology and behavior

Subfield: Ecology

Field: Environmental Science

Domain: Physical Sciences

Open Access status: diamond

Funder: Hrvatska Zaklada za Znanost

Awards: Land or sea: ecological and genetic aspects of habitat choice in the Common Tern, G6462038999