Iwaniuk, Andrew

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https://opus.uleth.ca/handle/10133/4634

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Browsing Iwaniuk, Andrew by Subject "Birds--Behavior"

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    Online repositories of photographs and videos provide insights into the evolution of skilled hindlimb movements in birds
    (Springer Nature, 2023) Gutiérrez-Ibáñez, Cristián; Amaral-Peçanha, Clara; Iwaniuk, Andrew N.; Wylie, Douglas R.; Baron, Jerome
    The ability to manipulate objects with limbs has evolved repeatedly among land tetrapods. Several selective forces have been proposed to explain the emergence of forelimb manipulation, however, work has been largely restricted to mammals, which prevents the testing of evolutionary hypotheses in a comprehensive evolutionary framework. In birds, forelimbs have gained the exclusive function of flight, with grasping transferred predominantly to the beak. In some birds, the feet are also used in manipulative tasks and appear to share some features with manual grasping and prehension in mammals, but this has not been systematically investigated. Here we use large online repositories of photographs and videos to quantify foot manipulative skills across a large sample of bird species (>1000 species). Our results show that a complex interaction between niche, diet and phylogeny drive the evolution of manipulative skills with the feet in birds. Furthermore, we provide strong support for the proposition that an arboreal niche is a key element in the evolution of manipulation in land vertebrates. Our systematic comparison of foot use in birds provides a solid base for understanding morphological and neural adaptations for foot use in birds, and for studying the convergent evolution of manipulative skills in birds and mammals.
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    Over or under: new phylogenetic insights in the evolution of head scratching in birds
    (Frontiers Media, 2025) Gutiérrez-Ibáñez, Cristián; Pellis, Vivien; Iwaniuk, Andrew; Pellis, Sergio
    Some birds scratch their heads by moving their foot ventrally underneath their wing and others do so by moving their foot over their wing. Two competing hypotheses have been proposed to explain the distribution of these patterns. The phylogenetic hypothesis proposes that the underwing route is a novel pattern evolved in birds as the evolution of wings meant that the foot did not have to move over the front leg as is it does in quadrupeds. Consequently, the overwing route is an atavism reflecting the tetrapod ancestry of birds. The biomechanical hypothesis proposes that body morphology or environmental context determines which pattern is most effective and so explains variation across species. Earlier attempts to test these hypotheses were limited by relatively small, taxonomically biased samples of birds that did not take phylogenetic relationships into account and with few morphological traits explicitly compared. The present study includes data for 1157 species from 92% of avian families and expands the number of morphological traits compared. The most plausible ancestral state, at least for Neoaves, was overwing scratching, turning the original phylogenetic hypothesis on its head. It is also clear from the analyses that head scratching pattern is a highly labile evolutionary trait that, in some orders, repeatedly switches between over and under wing patterns. Moreover, while some morphological traits biased the likely scratching pattern used in some clades, the biomechanical hypothesis failed to predict the pattern of scratching across all birds. The most likely explanation is that the two forms of scratching are independently evolved behavior patterns and that a yet to be determined reason can switch between patterns in different lineages.