Diet of tawny owls (<i>Strix aluco</i>) in relation to field vole (<i>Microtus agrestis</i>) abundance in a conifer forest in northern England

Petty, S. J.

doi:10.1111/j.1469-7998.1999.tb01045.x

Cited by 66 publications

(17 citation statements)

References 27 publications

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“…In the boreal zone, tawny owls mainly prey on voles, which fluctuate in numbers between years (Karell et al 2009a) and which have been found to follow irregular dynamics in recent years (Hörnfeldt et al 2005;Brommer et al 2010;Cornulier et al 2013). In years with poor availability of small mammals, tawny owls switch to utilise more alternative prey, mainly birds (Petty 1999), and they produce smaller broods or may skip breeding completely (Roulin et al 2003;Karell et al 2009a;Millon et al 2014). The tawny owls come in a reddish-brown (hereafter brown) and a grey highly heritable morph (Brommer et al 2005;Karell et al 2011a), which reside in the same geographical area and mate non-assortatively with respect to plumage colour (Brommer et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Specialist predation covaries with colour polymorphism in tawny owls

Karell

Kohonen

Koskenpato

2021

Behav Ecol Sociobiol

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Understanding intraspecific phenotypic variation in prey specialisation can help to predict how long-term changes in prey availability affect the viability of these phenotypes and their persistence. Generalists are favoured when the main food resources are unpredictable compared to specialists, which track the availability of the main prey and are more vulnerable to changes in the main food resource. Intraspecific heritable melanin-based colour polymorphism is considered to reflect adaptations to different environments. We studied colour morph-specific diet specialisation in a generalist predator, tawny owl (Strix aluco), during offspring food provisioning in relation to mammal prey density. We hypothesised that the grey morph, with higher fitness than the brown in Northern boreal conditions, is more specialised in mammalian prey than the brown morph, which in turn has higher fitness than the grey in the temperate zone. We found a higher diversity of prey delivered to the nest by brown fathers compared to grey ones, which also depended on the overall mammalian prey availability. Brown fathers provided proportionally fewer mammalian prey than grey in poor, but not in favourable mammal prey years. Our results suggest that the brown morph is more generalistic and reacts more strongly to variations in food supply than the grey morph, which may be a beneficial strategy in an unpredictable environment caused by environmental degradation. Significance statement Diet choice of a species may vary depending on fluctuations in the abundance of their food resource, but also within a population, there can be adaptations to use different food resources. The tawny owl exhibits a grey and a reddish-brown colour morph and is considered a generalist predator eating both mammal and bird prey. We find that the diet of the reddish-brown morph is more diverse than that of the grey. When the tawny owls’ main prey, small mammals, are abundant both colour morphs prey on mammals, but in years with less small mammals, the reddish-brown morph is more prone of switching to small bird predation than the grey. The generalist strategy of the brown morph is likely to be more favourable than a stricter specialisation in small mammals of the grey under recently reoccurring irregularities in small mammal dynamics.

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Section: Introductionmentioning

confidence: 99%

Specialist predation covaries with colour polymorphism in tawny owls

Karell

Kohonen

Koskenpato

2021

Behav Ecol Sociobiol

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“…The same situation takes place elsewhere, where proportions of main small mammal prey species are very similar to their share in the small mammal community (Southern, 1954;Jedrzejewski et al, 1994). Microtus voles are the other important prey group; they are more important in study areas with a large proportion of open spaces and also in the northern part of the Tawny Owl range (Petty, 1999;Sunde et al, 2001;Balciauskiene et al, 2005Balciauskiene et al, , 2006. Although more than half of the bird pairs in the studied territory had access to open spaces outside the forest, Microtus voles made up only a relatively small part of the diet.…”

Section: Discussionmentioning

confidence: 99%

“…Alternative prey can be represented by larger mammals, such as rabbits (Oryctolagus cuniculus Lilljeborg) and moles (Talpa europaea L.) (Southern, 1954), shrews (Sorex sp.) (Gruzdev and Likhachev, 1960;Delmee et al, 1978;Petty, 1999), or birds (Kirk, 1982;Jedrzejewski et al, 1994). In our case, the East European vole, lesser white-toothed shrew, and common spadefoot were alternative prey in spring and summer.…”

Section: Discussionmentioning

confidence: 99%

“…The Tawny Owl (Strix aluco L.) is adapted mainly to temperate deciduous forests (Petty and Saurola, 1997;Butyev et al, 2005), and is a well-studied example of a sedentary rodent-eating predator with a generalized feeding strategy (Petty, 1999;Newton, 2002). Bank voles (Myodes glareolus Schreber) and wood mice (Apodemus sp.)…”

Section: Introductionmentioning

confidence: 99%

“…dominate the Tawny Owl diet throughout the main part of its range (Cramp, 1985;Galeotti, 2001). These rodent species show noncyclic fluctuations in their numbers (Jedrzejewsky et al, 1996;Petty, 1999) but they are rather abundant in temperate forests. This allows the Tawny Owl to reach maximal densities in temperate broadleaved forests (Southern, 1970;Galeotti, 2001) and in broadleaved forests of the Mediterranean region (Salvati and Ranazzi, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Seasonal changes in Tawny Owl (Strix aluco) diet in an oak forest in Eastern Ukraine

Yatsiuk¹,

Filatova²

2017

Turk J Zool

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We analyzed seasonal changes in Tawny Owl (Strix aluco) diet in a broadleaved forest in Eastern Ukraine over 6 years (2007)(2008)(2009)(2010)(2011)(2012). Annual seasons were divided as follows: December-mid-April, April-June, July-early October, and late October-November. In total, 1648 pellets were analyzed. The most important prey was the bank vole (Myodes glareolus) (41.9%), but the yellow-necked mouse (Apodemus flavicollis) (17.8%) dominated in some seasons. According to trapping results, the bank vole was the most abundant rodent species in the study region. The most diverse diet was in late spring and early summer. Small forest mammals constituted the dominant group in all seasons, but in spring and summer their share fell due to the inclusion of birds and the common spadefoot (Pelobates fuscus). Diet was similar in late autumn, before the establishment of snow cover, and in winter. The relative representation of species associated with open spaces increased in winter, especially in years with deep snow cover, which may indicate seasonal changes in the hunting habitats of the Tawny Owl.

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Intraguild predator drives forest edge avoidance of a mesopredator

et al. 2016

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Abstract.Interactions between top predators and mesopredators of the same guild often result in habitat segregation restricting interactions to shared habitat edges. Although negative edge effects are recognized as important spatial patterns in the ecology of fragmented landscapes, the underlying mechanisms of predator-prey interactions resulting in negative edge effects remain unknown. To disentangle top-down effects of intraguild predators and bottom-up effects of shared resources on mesopredator spatial distribution, we recorded the occurrence of tawny owls Strix aluco in forests and their prey, the little owl Athene noctua in adjacent open areas over 2 yr across 687 km 2 in Southern Germany. We developed a new, asymmetrical dynamic two-species occupancy model investigating spatial interactions while accounting for imperfect detection. Little owl occupancy was strongly reduced within 150 m of forests, but only in the presence of tawny owls. Analysis of over 30 000 telemetry locations of 275 little owls showed that little owls strongly avoided areas closer than 150 m from the forest during range use. These results suggest that the negative edge effect is due to forest edge avoidance rather than direct predation. Potential confounding mechanisms such as food depletion or habitat avoidance at forest edges can be ruled out. Thus, top-down effects caused by avoidance of intraguild top predators shape the spatial distribution of mesopredators such as the little owl. While habitat complexity mitigates multitrophic interactions within habitats, it is expected to reinforce multitrophic interactions between habitats, potentially leading to the suppression of mesopredators from suitable habitats.

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Diet of tawny owls (Strix aluco) in relation to field vole (Microtus agrestis) abundance in a conifer forest in northern England

Cited by 66 publications

References 27 publications

Specialist predation covaries with colour polymorphism in tawny owls

Specialist predation covaries with colour polymorphism in tawny owls

Seasonal changes in Tawny Owl (Strix aluco) diet in an oak forest in Eastern Ukraine

Intraguild predator drives forest edge avoidance of a mesopredator

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