Natal dispersal and habitat choice in the colour polymorphic tawny owl (Strix aluco)
(2023) BION02 20222Degree Projects in Biology
- Abstract
- Organisms must aim to find suitable places to settle and reproduce, and this choice varies according to environmental and individual features. The choice of an adequate place can have crucial repercussions on the reproductive success and thus, animal fitness. In many species natal dispersal is a key process accounting for crucial implications for a species spatial distribution. Hence, natal dispersal strategies depend on morphological, physiological and behavioural features. Melanin-based colour polymorphism is a phenotypic trait associated with specific morphological and behavioural profiles, which can be a source of individual variation in dispersal strategies and habitat selection. According to the niche divergence hypothesis, species... (More)
- Organisms must aim to find suitable places to settle and reproduce, and this choice varies according to environmental and individual features. The choice of an adequate place can have crucial repercussions on the reproductive success and thus, animal fitness. In many species natal dispersal is a key process accounting for crucial implications for a species spatial distribution. Hence, natal dispersal strategies depend on morphological, physiological and behavioural features. Melanin-based colour polymorphism is a phenotypic trait associated with specific morphological and behavioural profiles, which can be a source of individual variation in dispersal strategies and habitat selection. According to the niche divergence hypothesis, species with a broader ecological niche are more likely to show colour polymorphism than those occupying narrower ecological niches. In this thesis, using a 27 years dataset of a population of the colour polymorphic tawny owl (Strix aluco) in relation to the proportions of different types of land coverage, I aimed to study natal dispersal distances of recruiting grey and pheomelanic reddish-brown (hereafter brown), habitat selection and if the natal territory configuration influences the choice of the breeding territory configuration. Following the suggestion that melanin-based colouration could be associated with a higher propensity to explore, I expected the brown morph to disperse longer distances. Stemming from the general theory of polymorphism, and the niche divergence hypothesis, I expected the two morphs would use different ecological niches. The third and final prediction was based to the natal habitat preference induction (NHPI), which states that the habitat preferences individuals show are shaped by their natal environments’ experience, thus I predicted there would be an association between the natal territory configuration and the breeding territory configuration. I found no differences in natal dispersal distances and habitat selection between the two morphs. I discuss these findings in the context of previous findings where no relation between colour polymorphism and dispersal distances was found, and the possible constraints of this analysis due to the variables used in this study. I found a positive association between the proportion of open areas in natal and breeding territories, which supports the hypothesis of NHPI on how early life experience shapes individual preference in the tawny owl. (Less)
- Popular Abstract
- Natal dispersal and habitat choice in the colour polymorphic tawny owl (Strix aluco)
Dispersal and habitat selection are important topics to study to understand how individuals assess which habitats are suitable to settle and breed. The choice of an adequate place can have crucial repercussions on the reproductive success and population structure. Melanin-based colouration is a heritable trait producing different colour morphs associated with different morphological and behavioural profiles. According to the niche divergence hypothesis, species with a broader ecological niche are more likely to show colour polymorphism than those occupying narrower ones, due to the process of disruptive selection. Natal habitat preference induction... (More) - Natal dispersal and habitat choice in the colour polymorphic tawny owl (Strix aluco)
Dispersal and habitat selection are important topics to study to understand how individuals assess which habitats are suitable to settle and breed. The choice of an adequate place can have crucial repercussions on the reproductive success and population structure. Melanin-based colouration is a heritable trait producing different colour morphs associated with different morphological and behavioural profiles. According to the niche divergence hypothesis, species with a broader ecological niche are more likely to show colour polymorphism than those occupying narrower ones, due to the process of disruptive selection. Natal habitat preference induction (NHPI) is an imprinting process where the habitat preferences individuals show are shaped by their natal environments’ experience.
In this study, using a 27 years dataset of a Swedish population of the colour polymorphic tawny owl (Strix aluco), I aimed to study natal dispersal distances, habitat selection and if the natal territory configuration influences the choice of the breeding territory configuration. Following the theoretical framework on melanin-based colouration, the general theory of polymorphism, the niche divergence hypothesis and the natal habitat preference induction, I expected the brown morph to disperse longer distances, the two morphs would use different ecological niches and that the natal habitat configuration would influence the breeding habitat configuration.
I found no differences in natal dispersal distances and habitat selection between the two morphs. Although this is contrary to my expectation and to previous observations in another colour polymorphic species, where the darker morph travelled longer distances, this result is in line with a similar study with tawny owls, where no main effect of colour polymorphism was found on the distances travelled. Regarding habitat selection, the results do not support my prediction. Despite the large variation in habitat configuration between observations, there was no evidence that the two morphs choose habitats differently.
Following the natal habitat preference induction, the results support that this imprinting process is in play here. In the particular case of the tawny owl, this imprinting process is expected because young tawny owls spend several months in their natal habitat under parental care, before departure and dispersing to find their own breeding territory. Moreover, tawny owls rarely perform breeding dispersal, therefore natal dispersal and habitat selection are likely to be the most important decisions they make.
Natal habitat preference induction can shape the habitat preferences tawny owls have when selecting breeding habitats. Such insight about the imprinting process occurring in early life stages is important because it suggests that the time they spend in the natal territory with their parents before dispersing is crucial in determining their choice on where to settle as adults. NHPI can lead to changes in distribution and adjustment towards new environments, because the habitat cues might change as a result of climate change. And these shifts on dispersal and habitat selection strategies might have great influence on fitness.
Master’s Degree Project in Conservation Biology, 60 credits, 2023.
Department of Biology, Lund University.
Supervisors: Dr. Patrik Karell, Dr. Arianna Passarotto, Dr. Chiara Morosinotto, Dr. Ruslan Gunko. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9113474
- author
- Fernandes Pires Pinto, Miguel
- supervisor
- organization
- course
- BION02 20222
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9113474
- date added to LUP
- 2023-04-14 12:29:33
- date last changed
- 2023-04-14 12:29:33
@misc{9113474,
abstract = {{Organisms must aim to find suitable places to settle and reproduce, and this choice varies according to environmental and individual features. The choice of an adequate place can have crucial repercussions on the reproductive success and thus, animal fitness. In many species natal dispersal is a key process accounting for crucial implications for a species spatial distribution. Hence, natal dispersal strategies depend on morphological, physiological and behavioural features. Melanin-based colour polymorphism is a phenotypic trait associated with specific morphological and behavioural profiles, which can be a source of individual variation in dispersal strategies and habitat selection. According to the niche divergence hypothesis, species with a broader ecological niche are more likely to show colour polymorphism than those occupying narrower ecological niches. In this thesis, using a 27 years dataset of a population of the colour polymorphic tawny owl (Strix aluco) in relation to the proportions of different types of land coverage, I aimed to study natal dispersal distances of recruiting grey and pheomelanic reddish-brown (hereafter brown), habitat selection and if the natal territory configuration influences the choice of the breeding territory configuration. Following the suggestion that melanin-based colouration could be associated with a higher propensity to explore, I expected the brown morph to disperse longer distances. Stemming from the general theory of polymorphism, and the niche divergence hypothesis, I expected the two morphs would use different ecological niches. The third and final prediction was based to the natal habitat preference induction (NHPI), which states that the habitat preferences individuals show are shaped by their natal environments’ experience, thus I predicted there would be an association between the natal territory configuration and the breeding territory configuration. I found no differences in natal dispersal distances and habitat selection between the two morphs. I discuss these findings in the context of previous findings where no relation between colour polymorphism and dispersal distances was found, and the possible constraints of this analysis due to the variables used in this study. I found a positive association between the proportion of open areas in natal and breeding territories, which supports the hypothesis of NHPI on how early life experience shapes individual preference in the tawny owl.}},
author = {{Fernandes Pires Pinto, Miguel}},
language = {{eng}},
note = {{Student Paper}},
title = {{Natal dispersal and habitat choice in the colour polymorphic tawny owl (Strix aluco)}},
year = {{2023}},
}