Väitös (biologia): MSc Charlotte Perrault
Aika
31.1.2025 klo 12.00 - 16.00
MSc Charlotte Perrault esittää väitöskirjansa ”An exploration of ecological processes underlying fitness differences in colour polymorphic tawny owls” julkisesti tarkastettavaksi Turun yliopistossa perjantaina 31.1.2025 klo 12.00 (Turun yliopisto, Natura, luentosali IX, Turku).
Vastaväittäjänä toimii apulaisprofessori Rose Thorogood (Helsingin yliopisto) ja kustoksena professori Jon Brommer (Turun yliopisto). Tilaisuus on englanninkielinen. Väitöksen alana on biologia.
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Tiivistelmä väitöstutkimuksesta / Summary of the Doctoral Dissertation:
Climate change is making our world warmer and in consequence, making snowy winters rarer. This change in landscape is affecting animals that rely on camouflage and insulation to survive. It is well known that prey animals depend on camouflage to stay hidden from predators. Still, predators also count on their camouflage abilities to not be detected by their prey when hunting. When their environment is changing, due to climate change, animals’ survival is also expected to change. The tawny owl, a predator species which can be born grey or brown, is a good example to study the effect of landscape change on predators. It is already known that grey owls have a camouflage advantage when there is snow in the environment compared to brown owls which are easier to detect in the snow. Grey owls also have a higher survival rate in snowy winters than brown owls. So, what could explain the difference in survival between the two colours of tawny owls? In my thesis, I studied the behaviour and the insulation of tawny owls in different environmental conditions. First, I showed that when the tawny owls were placed in a new environment, the brown owls were choosing more often to sit in an open area, which suggests they are bolder than the grey owls since they are choosing a riskier resting place. Then, I studied their camouflage efficiency by observing the behaviour of small passerines which are used to harass owls when they are resting during the day. Birds harassed brown owls more often in snowy conditions and harassed grey owls more when there was no snow. Finally, I looked at the insulation properties of tawny owls’ feathers from nine populations dispatched across Europe. While feather insulation changed according to the location of the owls within Europe, the colour of the owl did not make a difference. My findings suggest that grey and brown tawny owls have different advantages depending on the environmental conditions they live in and more especially the snow cover. Thus, as winters get warmer and snow becomes rarer, brown tawny owls might become more common in northern areas in the future.
Vastaväittäjänä toimii apulaisprofessori Rose Thorogood (Helsingin yliopisto) ja kustoksena professori Jon Brommer (Turun yliopisto). Tilaisuus on englanninkielinen. Väitöksen alana on biologia.
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Tiivistelmä väitöstutkimuksesta / Summary of the Doctoral Dissertation:
Climate change is making our world warmer and in consequence, making snowy winters rarer. This change in landscape is affecting animals that rely on camouflage and insulation to survive. It is well known that prey animals depend on camouflage to stay hidden from predators. Still, predators also count on their camouflage abilities to not be detected by their prey when hunting. When their environment is changing, due to climate change, animals’ survival is also expected to change. The tawny owl, a predator species which can be born grey or brown, is a good example to study the effect of landscape change on predators. It is already known that grey owls have a camouflage advantage when there is snow in the environment compared to brown owls which are easier to detect in the snow. Grey owls also have a higher survival rate in snowy winters than brown owls. So, what could explain the difference in survival between the two colours of tawny owls? In my thesis, I studied the behaviour and the insulation of tawny owls in different environmental conditions. First, I showed that when the tawny owls were placed in a new environment, the brown owls were choosing more often to sit in an open area, which suggests they are bolder than the grey owls since they are choosing a riskier resting place. Then, I studied their camouflage efficiency by observing the behaviour of small passerines which are used to harass owls when they are resting during the day. Birds harassed brown owls more often in snowy conditions and harassed grey owls more when there was no snow. Finally, I looked at the insulation properties of tawny owls’ feathers from nine populations dispatched across Europe. While feather insulation changed according to the location of the owls within Europe, the colour of the owl did not make a difference. My findings suggest that grey and brown tawny owls have different advantages depending on the environmental conditions they live in and more especially the snow cover. Thus, as winters get warmer and snow becomes rarer, brown tawny owls might become more common in northern areas in the future.
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