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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Body Condition in the Tawny Owl Strix aluco near the Northern Limit of Its Range: Effects of Individual Characteristics and Environmental Conditions
No full textThe body condition of boreal species of vole-eaters seems to vary largely according to fluctuations in vole populations and weather conditions of the preceding winter. I studied females and males of the Tawny Owl Strix aluco of temperate origin near the northern limit of the species’ range in southern Finland to reveal if they show similar patterns to the boreal species. Winter weather conditions before breeding seemed to have pronounced effects on the food availability of Tawny Owls. In females, intrinsic factors such as colour morph and age, as well as the body condition of the mate and the stage of the season (Julian date), governed body condition. In males, only age and Julian date showed pronounced relationships with body condition. The results suggest that deep snow cover protects vole populations through winter until spring better than a minor amount of snow and that frequent temperature fluctuations around the freezing point in early spring make voles more available for owls that are preparing for breeding. This was also reflected positively in the body condition of female owls. Probably due to the efficient use of alternative prey, the effects of fluctuating vole populations on the body condition of Tawny Owls are, in general, only moderate
Breeding phenology in Great and Blue Tits (Parus spp.): are urban populations more resistant to climate change than rural ones?
No full textUrbanization and climate change are two environmental factors that have most prominently affected breeding phenology of birds during recent decades. We examined such relationships in rural, suburban and urban nest box populations of Great Tits Parus major and Blue Tits P. caeruleus in the capital region of Finland in the 1980s and 1990s. We expected that mild winters and high spring temperatures may advance the breeding season of tits, but less so in urban habitats, where breeding should in any case start earlier than elsewhere. On average, Blue Tits began egg laying a few days earlier in spring than Great Tits. Contrary to expectations, tits bred later in the urban parks of the city than in other habitats, whereas breeding was earliest in suburban areas. It seems that these intermediate habitats, in some way, offer the advantages of both rural and urban habitats. During the study period, the timing of breeding in tits showed advancing temporal trends in rural habitats, and in the Blue Tit also in urban habitats. The effect of increasing winter temperatures on laying dates was mainly minor, but a significant delay emerged in urban Great Tits. The main effect of increasing April temperatures on laying dates was a significant advancement. In urban habitats, however, the advancing effect was in Great Tits significantly stronger and in Blue Tits significantly weaker than in other habitats. The results suggest that breeding of tits may advance also with warming climate but some urban populations might be more resistant to climate change than rural ones
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