Winter survival and breeding success of dominant and subordinate Willow Tits Parus montanus

We studied the effect of winter rank on survival rate and reproductive success in Willow Tits Parus montanus, a resident passerine living in dominance-structured flocks during the nonbreeding season, in 6 years. Winter survival was dependent on both the birds' age and rank. Adults survived better than first-year birds, and within first-year males, dominants survived better than subordinates. In other sex and age classes, rank did not contribute to survival. Although first-year males were in excess among nonbreeders, no connection existed between breeding status and rank. Female rank did not explain the variation in the start of laying, clutch size, number of fledglings or recruit production. We conclude that social status in Willow Tits affects individual fitness mainly through rank-dependent survival. Acquiring a high rank position seems to be most important for first-year birds, especially first-year males.     

Effect of habitat, date of laying and density on clutch size of the Great Tit Parus major in northern Finland

The sizes of 1034 Great Tit clutches were studied at the Oulu area (c. 65°N, 25°30'E) in northern Finland. The average size was 9.86 eggs in the first clutch and 7.51 in the second in 13 study areas. The decrease in clutch size from the first to the second laying was most pronounced in those females laying the largest first clutches.
Irrespective of habitat, the clutch size was larger in the sparsely populated areas than in the densest area (Taskila). The clutch size decreased according to the season in all the areas, but this was not as pronounced in Taskila as in the other areas.
The annual average size of the first clutches was inversely related to the breeding density and pronouncedly so to the mean dale of laying. The latter was suggested to be an adaptation to the short season in the northern areas.
An analysis of data from 27 study areas in Europe, north of the Mediterranean region, suggests that the clutch size does not vary with latitude or longitude.     

Genetic variation of the Siberian tit Parus cinctus populations at the regional level: a mitochondrial sequence analysis

We studied the matrilinear genetic structure of the Siberian tit Parus cinctus by sequencing 911 bp of the mitochondrial control region of 56 birds from Fennoscandia and 3 from Yakutia, central Siberia, representing subspecies P. c. lapponicus and P. c. cinctus , respectively. One major haplotype comprised 35.7% of all birds and was present in all Fennoscandian populations. Sequence variation of 5 museum specimens from Norway fitted with the pattern of the present-day birds. The nucleotide diversity was 0.00205±0.00025 in the Fennoscandian population and no population structuring was detected. The star-like phylogeny suggests a recent expansion of the population size in the evolutionary time scale. A modern decline of the population size from 200 000 pairs to 50 000 pairs in Finland has resulted from cutting and fragmentation of old-growth forests, but the effects of this could not yet be detected in the mtDNA pattern. However, the nucleotide diversity differed among populations being the highest at Kuusamo, close to the Russian border. Conceivably, the gene flow maintained by the substantial migration of Siberian tits is sufficient to prevent differentiation of local populations in Fennoscandia. Presumably the large conservation areas in NE Finland and on the Russian side of the border contribute to the high genetic variation observed in the Kuusamo population. Comparison of the mtDNA phylogeny of the Siberian tit with the phylogenies of the great tit, the blue tit and the willow tit showed that the Siberian tit and some other non-migratory species of the foliage gleaning guild share similar post glacial histories in the western palaearctic.     

Histochemical demonstration of carbonic anhydrase activity in the uterus

Summary Positive histochemioal reaction for carbonic anhydrase (CAH) activity was observed in the glandular and lining epithelium of human and rat uteri. The CAH activity in the rat endometrium showed cyclic changes during the estrous cycle. Only one main component of CAH activity was revealed by electrophoresis, under conditions when the erythrocytes showed several isozymes.     

Comparison of methods used in zooplankton sampling and counting in the joint Russian-Finnish evaluation of the trophic state of Lake Ladoga

The results of a joint Russian-Finnish investigation on zooplankton in Lake Ladoga are presented, and a comparison is made between two sampling techniques, tube sampler and plankton net, and between two counting methods. The precision of subsampling and sampling is further discussed on the basis of zooplankton data gathered in Lake Saimaa, Finland. The comparison clearly indicates that a tube sampler is required for reliable sampling of small-sized animals, while a plankton net saves time and is a more economical sampler for large, rare or active animals. The comparison between the results obtained by Finnish and Russian workers, using different counting procedures, shows that the main groups of crustacean zooplankton are similarly counted and identified in the two laboratories.