The screech owl : its life history and population ecology in northern Ohio /

VanCamp, Laurel F.; Henny, Charles J.

doi:10.5962/bhl.title.87043

Cited by 42 publications

(7 citation statements)

References 17 publications

(23 reference statements)

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“…Breeding Western Screech-owls banded at nest boxes in southern Idaho were observed to have a mean life span of 1.73 years (range 1-8 years, n = 48) for females and 1.83 years (range 1-8 years, n = 30) for males (Cannings and Angell 2001). Similar studies with Eastern Screech-Owls observed annual survival of 59% in suburban areas and 55% in rural areas (Gehlbach 1994), and 61%-67% annual survival for all adults in northern Idaho (Van Camp and Henny 1975). Our results are quite similar to the observations of these banded populations, with a range of 28%-50% turnover based on call structure alone.…”

Section: Discussionmentioning

confidence: 58%

Vocal individuality as a potential long-term monitoring tool for Western Screech-owls, Megascops kennicottii

Tripp

Otter

2006

Can. J. Zool.

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Recent studies suggest that individually distinctive vocalizations found in many avian species can be used in population monitoring. In this study we assessed whether vocal identification of male Western Screech-owls (Megascops kennicottii (Elliot, 1867)) was possible, and if it could be applied as a long-term monitoring tool. Recordings were collected between 2001 and 2003 from 28 territories on southern and central Vancouver Island. As a quantitative descriptor of the calls, a total of 17 variables were measured from each of 1125 calls. A discriminant function analysis resulted in 92.3% of calls being correctly classified to individual territories within one season and 87.3% of calls in a cross-validation of the model. Variables that showed the greatest discriminant ability included length of call, internote distance between first note and second note, and number of notes per call. Of the 14 territories that had owl calls recorded over 2 years, 4 appeared to be occupied by a different individual in the 2nd year, 7 had calls that were consistent between years, and 3 had calls that were ambiguously classified between years. Our results suggest that Western Screech-owl calls have enough individually recognizable characteristics to aid in the tracking of individuals both within and between years, allowing for long-term monitoring of individuals.Résumé : Des études récentes laissent croire que les vocalises individuelles distinctes qui existent chez plusieurs espèces d'oiseaux pourraient servir à la surveillance des populations. Nous évaluations dans notre étude la possibilité d'identifier par leurs vocalises les mâles du petit-duc des montagnes (Megascops kennicottii (Elliot, 1867)) et d'utiliser ces vocalises comme outil de surveillance à long terme. Des enregistrements ont été réalisés de 2001 à 2003 dans 28 territoires dans le sud et le centre de l'île de Vancouver. Pour décrire quantitativement ces vocalises, nous avons mesuré un ensemble de 17 variables dans chacun des 1125 appels. Une analyse des fonctions discriminantes associe correctement 92,3 % des appels faits dans une même saison à leur territoire correspondant et 87,3 % des appels dans un essai de validation croisée du modèle. Les variables qui offrent la plus grande valeur discriminante sont, entre autres, la longueur de l'appel, l'intervalle entre les deux premières notes et le nombre de notes par appel. Parmi les 14 territoires dans lesquels des appels du petitduc ont été enregistrés au cours de 2 années, 4 sites semblent être occupés par un individu différent la 2 ième année, 7 ont des appels qui concordent pendant les 2 années et 3 ont des classifications ambiguës d'une année à l'autre. Nos résultats indiquent que les appels des petits-ducs possèdent suffisamment de caractéristiques individuelles identifiables pour servir à suivre les individus au cours d'une année et d'une année à l'autre, ce qui rend possible une surveillance à long terme des individus.[Traduit par la Rédaction]

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Section: Discussionmentioning

confidence: 58%

Vocal individuality as a potential long-term monitoring tool for Western Screech-owls, Megascops kennicottii

Tripp

Otter

2006

Can. J. Zool.

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“…Previous studies in the tawny owl, screech owl, and scops owl suggested that reddish owls have a higher survival in warm–wet years than in cold–dry years (Van Camp & Henny, 1975; Mosher & Henny, 1976; Gehlbach, 1986; Galeotti & Cesaris, 1996; Galeotti et al ., 2009). Thus, the degree of pheomelanin‐based coloration may be associated with the ability to cope with warm climates, whereas a non‐pheomelanic coloration may be adapted to colder climates.…”

Section: Discussionmentioning

confidence: 99%

“…In many owl species, individuals display one of several colour morphs that vary in the degree of reddishness. In Italy, the Eurasian scops owl's reddish morph increased in proportion during the last century (Galeotti et al ., 2009); in Italy, rufous tawny owls ( Strix aluco ) were found dead more often in cool‐dry years and grey individuals in warm–wet years (Galeotti & Cesaris, 1996); and, in North America, rufous coloured screech owls ( Otus asio ) appear to be unfit during cold, dry and snowy weather compared to grey individuals (Van Camp & Henny, 1975; Mosher & Henny, 1976; Gehlbach, 1986). Thus, from these intraspecific patterns, we predict that owl species are more often reddish near the equator than near the poles, which may indicate that pheomelanism is not selectively neutral with respect to climate change.…”

Section: Introductionmentioning

confidence: 99%

Owl melanin-based plumage redness is more frequent near than away from the equator: implications on the effect of climate change on biodiversity

Roulin

Burri

Antoniazza

2011

Biological Journal of the Linnean Society

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Climate change acts as a major new selective agent on many organisms, particularly at high latitudes where climate change is more pronounced than at lower latitudes. Studies are required to predict which species are at a high risk of extinction and whether certain phenotypes may be more affected by climate change than others. The identification of susceptible phenotypes is important for evaluating the potential negative effect of climate change on biodiversity at the inter-and intraspecific levels. Melanin-based coloration is an interesting and easily accessible candidate trait because, within certain species, reddish pheomelanin-based coloration is associated with adaptations to warm climates. However, it is unclear whether the same holds among species. We tested one prediction of this hypothesis in four owl genera (wood, scops, screech, and pygmy owls), namely that darker reddish species are more prevalent near the equator than polewards. Our comparative analysis is consistent with this prediction for the northern hemisphere, suggesting that pale reddish species may be adapted to cold climates and dark reddish species to warmer climates. Thus, climate change may have a larger negative impact on pale pheomelanic owls and favour dark pheomelanic species.

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“…Such intraspecific colour variation is independent of sex, age and season (Butcher & Rohwer, 1989), and evidence for birds suggests a strong genetic control of colour morphs (e.g. Van Camp & Henny, 1975; Roulin, Richner & Ducrest, 1998; Krüger, Lindstrom & Amos, 2001; Roulin & Dijkstra, 2003). Following the seminal review by Huxley (1955), a number of papers have treated this topic in single avian species or genera (see Galeotti et al ., 2003 and references therein).…”

Section: Introductionmentioning

confidence: 99%

The niche variation hypothesis and the evolution of colour polymorphism in birds: a comparative study of owls, nightjars and raptors

Galeotti

Rubolini

2004

Biological Journal of the Linnean Society

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We studied the evolution of colour polymorphism in diurnal raptors, owls and nightjars, the avian taxa in which this trait is most widespread, in relation to species ecological niche width and diet. Two main mechanisms have been put forward to explain the maintenance of polymorphism, namely apostatic selection and disruptive selection. The niche variation hypothesis states that species with broader ecological niches should be more variable compared with those with narrow niches because of the action of disruptive selection; the apostatic selection hypothesis conversely suggests that intraspecific colour variation should be promoted in predators by prey forming an avoidance image for the more common colour morph. Our aim was to determine if colour polymorphism occurrence was associated with broad ecological niches as predicted by the niche variation hypothesis, or with predation on intelligent and sharp-sighted prey as predicted by the avoidance image hypothesis. Pairwise comparisons were made between pairs of closely related species differing in variables expected to influence the occurrence of polymorphism. We found that polymorphic species of all three groups showed wider and more continuous distribution ranges, frequented many different habitats, both open and closed, and lived in seasonally alternating dry/wet climates. Polymorphic species were more migratory compared with monomorphic ones, and they showed an activity pattern covering both day and night. Conversely, colour polymorphism was not higher in species preying on birds and mammals. All these findings support the hypothesis that colour polymorphism evolved in bird species with wider niche breadth and not in species preying on intelligent prey. Therefore, we propose that disruptive selection may be the main mechanism maintaining colour polymorphism in these bird groups by favouring different morphs in different environmental conditions.

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The screech owl : its life history and population ecology in northern Ohio /

Cited by 42 publications

References 17 publications

Vocal individuality as a potential long-term monitoring tool for Western Screech-owls, Megascops kennicottii

Vocal individuality as a potential long-term monitoring tool for Western Screech-owls, Megascops kennicottii

Owl melanin-based plumage redness is more frequent near than away from the equator: implications on the effect of climate change on biodiversity

The niche variation hypothesis and the evolution of colour polymorphism in birds: a comparative study of owls, nightjars and raptors

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