Väitös (biologia): MSc Sajjad (Farshad) Vakili

MSc Sajjad (Farshad) Vakili esittää väitöskirjansa ”Incubation behaviour under multiple stressors: predation risk and exposure to per- and polyfluoroalkyl substances in long-lived waterfowl” julkisesti tarkastettavaksi Turun yliopistossa perjantaina 28.8.2026 klo 12.00 (Turun yliopisto, Agora, XXI-luentosali, Vesilinnantie 3, Turku).

Vastaväittäjänä toimii professori Bjørn Munro Jenssen (Norwegian University of Science and Technology, Norja) ja kustoksena dosentti Céline Arzel (Turun yliopisto). Tilaisuus on englanninkielinen. Väitöksen alana on biologia.

Tiivistelmä väitöstutkimuksesta:

Wild animals face multiple challenges during the reproductive period. Parents must protect their developing embryos while balancing investment in reproduction with their own survival. On the one hand, predation is a leading cause of reproductive failure in wildlife. However, in addition to predators, wildlife is increasingly exposed to human-induced environmental pollutants, including per- and polyfluoroalkyl substances (PFAS, or “forever chemicals”). My thesis examines how incubating birds respond to predation risk and PFAS exposure.

First, I investigated anti-predator behaviour in incubating female common goldeneyes (Bucephala clangula). I found that individuals consistently differed in boldness–some females were bolder than others–but that behaviour also changed with age and reproductive value. Females became bolder as they aged and when incubating larger clutches. However, older females whose nests contained eggs laid by other females (parasitic eggs) became more cautious, suggesting that birds adjust their reproductive investment according to its expected costs. Additionally, this work provided rare field evidence in birds that the boldest incubating female goldeneyes faced a higher risk of being killed during predator attacks, demonstrating that risk-taking can carry survival cost.

Second, I examined whether exposure to PFAS was associated with incubation behaviour in female common goldeneyes and common eiders (Somateria mollissima). By placing microchips inside artificial eggs, I monitored how females kept their eggs warm and how often they turned them during incubation. Higher concentrations of PFAS were associated with lower egg temperature in female eiders, while female goldeneyes showed weak evidence of changes in egg-turning behaviour. Although I found no clear evidence that these associations were explained by hormones, several hormones involved in stress responses, energy mobilization, and parental care were linked to incubation behaviour, highlighting the important role of hormones in behavioural regulations in breeding birds.

These findings suggest that although breeding animals differ consistently in behaviour, their responses remain flexible and depend on environmental conditions. By improving our understanding of behavioural responses of birds to multiple environmental stressors, this work contributes to efforts to conserve bird populations.