Tapio Solonen

Does plumage colour signal fitness in the tawny owl Strix aluco ?

Journal of Avian Biology

Significance of plumage colour for winter survival in the Tawny Owl ( Strix aluco ): revisiting the camouflage hypothesis

Ibis

Effects of interspecific coexistence on laying date and clutch size in two closely related species of hole-nesting birds

The Journal of animal ecology, Jan 12, 2018

Coexistence between great tits Parus major and blue tits Cyanistes caeruleus, but also other hole... more Coexistence between great tits Parus major and blue tits Cyanistes caeruleus, but also other hole-nesting taxa, constitutes a classic example of species co-occurrence resulting in potential interference and exploitation competition for food and for breeding and roosting sites. However, the spatial and temporal variations in coexistence and its consequences for competition remain poorly understood. We used an extensive database on reproduction in nest boxes by great and blue tits based on 87 study plots across Europe and Northern Africa during 1957-2012 for a total of 19,075 great tit and 16,729 blue tit clutches to assess correlative evidence for a relationship between laying date and clutch size, respectively, and density consistent with effects of intraspecific and interspecific competition. In an initial set of analyses, we statistically controlled for a suite of site-specific variables. We found evidence for an effect of intraspecific competition on blue tit laying date (later l...

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Interspecific variation in the relationship between clutch size, laying date and intensity of urbanization in four species of hole-nesting birds

Ecology and Evolution, 2016

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Vuosaaren kaatopaikan täyttöalueen linnusto

Metal levels of feathers in birds of various food chains in southern Finland

Ornis Fennica, 1999

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Effect of Sparrowhawk Accipiter nisus predation on forest birds in southern Finland

Ornis Fennica, 1997

Predation patterns of the Sparrowhawk Accipiter nisus and the vulnerability of the prey species w... more Predation patterns of the Sparrowhawk Accipiter nisus and the vulnerability of the prey species were studied at territorial and local population levels, on the basis of four data sets of breeding bird censuses and prey remnant samples collected near nests. The magnitude of predation pressure on breeding populations of prey species was estimated. During the breeding season, of the various avian prey individuals (n = 1674 ; 62 species), 17 .2% were derived from habitats other than forest. The most important prey species by number included Fringilla coelebs (17.1%), Parus major (10.7%), Phylloscopus trochilus (7 .8%), Passer domesticus (7 .2%), Erithacus rubecula (6 .9%), Anthus trivialis (5 .4%), and Turdus philomelos (5 .4%). The prey samples mainly included species and individuals weighing 15-30 g. The mean weight of prey was 26 .6 g (n =1 666). The most important prey species by weight were F. coelebs (13.4%), T. philomelos (13.4%), P. domesticus (8 .2%), P. major (7 .3%), and T. pilaris (6 .6%). Fifteen species were significantly less vulnerable to Sparrowhawk predation than expected on the basis of their numbers in the environment, in one or more of the data sets studied, while seven species were, in general, more vulnerable than expected. Low vulnerability values were showed especially by Ph. trochilus, Regulus regulus, Sylvia borin, T. merula, Ph. sibilatrix, and S. communis. Especially vulnerable species seemed to be P. caeruleus, P. major, F. hypoleuca, Carduelis chloris and T. philomelos. Predation on adult birds during the three months of the breeding season was about 5-6% .

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Nykyiset uhanalaisten lintulajien luettelot sopivat huonosti suojelun työvälineiksi

Clutch size of a vole-eating bird of prey as an indicator of vole abundance

Environmental monitoring and assessment, 2015

Voles are often considered as harmful pests in agriculture and silviculture. Then, the knowledge ... more Voles are often considered as harmful pests in agriculture and silviculture. Then, the knowledge of their abundance may be of considerable economical importance. Commonly used methods in the monitoring of vole abundances are relatively laborious, expensive, and spatially quite restricted. We demonstrate how the mean clutch size of the tawny owl Strix aluco may be cost-effectively used to predict relative densities of voles over large areas. Besides installing a number of suitable nest boxes, this vole monitoring system primarily includes only the inspection of the nest boxes and counting the number of tawny owl eggs found two times during a few weeks period in spring. Our results showed a considerable agreement between the fluctuations in the mean clutch size of tawny owls and the late spring abundance indices of small voles (Myodes, Microtus) in our study areas in southern Finland. The mean clutch size of the tawny owl reflected spring vole abundance over the spatial range examined...

Clutch size of a vole-eating bird of prey as an indicator of vole abundance

Environmental Monitoring and Assessment, 2015

Voles are often considered as harmful pests in agriculture and silviculture. Then, the knowledge ... more Voles are often considered as harmful pests in agriculture and silviculture. Then, the knowledge of their abundance may be of considerable economical importance. Commonly used methods in the monitoring of vole abundances are relatively laborious, expensive, and spatially quite restricted. We demonstrate how the mean clutch size of the tawny owl Strix aluco may be cost-effectively used to predict relative densities of voles over large areas. Besides installing a number of suitable nest boxes, this vole monitoring system primarily includes only the inspection of the nest boxes and counting the number of tawny owl eggs found two times during a few weeks period in spring. Our results showed a considerable agreement between the fluctuations in the mean clutch size of tawny owls and the late spring abundance indices of small voles (Myodes, Microtus) in our study areas in southern Finland. The mean clutch size of the tawny owl reflected spring vole abundance over the spatial range examined, suggesting its suitability for general forecasting purposes. From the pest management point of view, an additional merit of the present method is that it may increase numbers of vole-eaters that provide biological control of vole populations.

Nest-sites of the Common Buzzard Buteo buteo in Finland

Ornis Fennica

Nest-sites TAPIO SOLONEN of the Common Buzzard Buteo The function of the nest in birds is to prov... more Nest-sites TAPIO SOLONEN of the Common Buzzard Buteo The function of the nest in birds is to provide shelter for the eggs and nestlings, , especially against potential predators. The nest-sites are accordingly so selected that they are either well concealed or as inaccessible as possible. Some species meet these requirements by selecting their nest-sites from a wide range of possible kinds (eurytopic), while others make their choice from a much sma.ller number of alternatives (stenotopic ; see also Newton 1979). Of the two Finnish Buteo species, the northern Rough-legged Buzzard B. lagopus

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The growth of Kestrel nestlings in southern Finland

Annales Zoologici Fennici

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Stability patterns of populations in a southern Finnish bird community

Memoranda - Societatis pro Fauna et Flora Fennica

Agriculture and birdlife in Finland. A review

Ornis Fennica

Arable land in Finland covers about 2.5 million hectares, distributed among cereals (47 %), sown ... more Arable land in Finland covers about 2.5 million hectares, distributed among cereals (47 %), sown grasslands (37 %) and other crops (e .g . potato, sugar-beet) . Agricul- tural habitats in Finland support a total of about 50 bird species, but most of these use other habitats as well . About 15 species nest and forage on cultivated fields, whereas the others use them only as foraging grounds. Most bird species of agricultural habitats feed upon soil invertebrates (c . 40 %) or insects (c . 30 %), but there are also a few mainly herbivorous species and some carnivorous predators preying upon birds and mammals. The short-distance and long-distance migrants each form nearly 40 % of the species, while the rest are more or less sedentary species. In recent decades, the area of cereals has increased steadily, whereas that of sown grasslands, natural meadows and pastures has decreased. Fields have become more uniform owing to increasing subsurface drainage and specialization . Intensificatio...

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Effect of the cold winter 1978/79 on breeding land bird densities in a study area in southern Finland

Spruce-frequenting arthropods as winter food for birds

Efficiency of the line transect and point count methods in a south Finnish forest area

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Mercury in Finnish Sparrowhawks Accipiter nisus

Ornis Fennica

The mercury content of the Sparrowhawk Accipiter nisus was studied from feath- ers of museum spec... more The mercury content of the Sparrowhawk Accipiter nisus was studied from feath- ers of museum specimens and from moulted feathers collected from nesting ter- ritories . The mercury contents of the samples dating from 1899 to the early 1980s varied from 1 to 42 Ng/g, being most often about 2-5 Elg/g . The mercury levels of some prey species of the Sparrowhawk were relatively high . In Spar- rowhawks, significantly elevated mercury levels were recorded in the samples from the second half of the century, and high values predominated in the samples from the 1960s . These were followed by significantly lower values but the samples from the late 1970s and early 1980s also showed many high and some exception- ally high concentrations . The many interacting factors complicate assessment of the role of mercury in the breeding success and population changes of Finnish Sparrowhawks, but some sublethal effects are probable.

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Nest distribution of the Pied Flycatcher Ficedula hypoleuca in an area saturated with nest-boxes

Annales Zoologici Fennici

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Impact of Dominant Predators on Territory Occupancy and Reproduction of Subdominant Ones within a Guild of Birds of Prey

The Open Ornithology Journal, 2011

The study upon which this article is based examined the interspecific relationships between three... more The study upon which this article is based examined the interspecific relationships between three differentsized species, both before and during breeding, within a guild of birds of prey in southern Finland between 1997 and 2007. The study sought to examine how the territory occupancy and fledgling production of the smaller (subdominant) species was related to the vicinity of a larger (dominant) species. Inverse relationships were thought to suggest effects of potential intraguild predation. Three key relationships emerged. Firstly, the vicinity of the dominant eagle owl had no significant effect on the occupancy of nesting territories of the subdominant northern goshawk, while the fledgling production of the goshawk increased as the distance from the dominant owl species increased. Secondly, a significant positive relationship was found between the occupancy of the nearest neighbour nesting territories of the eagle owl and the tawny owl. However, the vicinity of the eagle owl had no significant effect on tawny owl reproduction. Thirdly, the occupation of tawny owl territories showed a nearly significant association with the nesting territories of the northern goshawk. However, no significant relationship was found between the vicinity of nearest neighbour nesting territories of the northern goshawk and fledgling production of the tawny owl. The results of this study suggest that depressing reflections of intraguild predation may be expected when the populations of guild members share similar nest sites or if the nest sites of subdominant members of the guild are accessible for dominant members, or in locally unstable populations of less site-tenacious species that show rapid turnover of individuals rather than in strictly site-tenacious longterm territorial species.

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