National agri-environment schemes (AESs) aim to promote sustainable farming and protect farmland biodiversity. For efficient maintenance of biodiversity, it is essential to understand the habitat requirements of fauna, and its responses to farming practices. This study examined the importance of different habitat characteristics and habitat heterogeneity for farmland birds in boreal agricultural landscapes, focusing on species in open arable habitats (true field species) and bushy field-edge habitats. Density, species richness, and species composition were studied in a multivariate space, and along environmental gradients. The relevance of the biodiversity-related measures of the Finnish AES regarding the habitat needs of farmland birds was examined. Non-cropped habitat heterogeneity (especially open ditches and habitat patch richness) increased the density and species richness. Crop diversity increased the species richness of true field species. Ordinations revealed a gradient from large open arable to small field areas, and a relation to habitat heterogeneity. The AES places insufficient emphasis on biodiversity issues.

Failure to detect a species in an area where it is present is a major source of error in biological surveys. We assessed whether it is possible to optimize single-visit biological monitoring surveys of highly dynamic freshwater ecosystems by framing them a priori within a particular period of time. Alternatively, we also searched for the optimal number of visits and when they should be conducted. We developed single-species occupancy models to estimate the monthly probability of detection of pond-breeding amphibians during a four-year monitoring program. Our results revealed that detection probability was species-specific and changed among sampling visits within a breeding season and also among breeding seasons. Thereby, the optimization of biological surveys with minimal survey effort (a single visit) is not feasible as it proves impossible to select a priori an adequate sampling period that remains robust across years. Alternatively, a two-survey combination at the beginning of the sampling season yielded optimal results and constituted an acceptable compromise between sampling efficacy and survey effort. Our study provides evidence of the variability and uncertainty that likely affects the efficacy of monitoring surveys, highlighting the need of repeated sampling in both ecological studies and conservation management.

Research using biometric data relies on consistent measurements within, and often among, observers. However, research into the relative importance of intra- and inter-observer variability is limited. More importantly, the influence of biometric variability on accurate quantification of biometric-based condition indices has not been analysed: it is unclear whether multiple errors become magnified or cancel one another out. Here, we quantify intra- and inter-specific variability in multiple biometrics, and derived condition indices, using museum bird specimens. Inter-observer variability was higher than intra-observer variability for all parameters. Measurement error (ME) varied from < 1% to > 50% for different biometrics. ME was magnified in condition estimates, reaching > 80% within-observers and > 90% among-observers. Significant differences in mean measurements were found for 17% and 67% of biometrics within-and among-observers, respectively; for condition indices, the figures were 50% and 67%, respectively. We discuss the implications of these findings for research into species' ecology, taxonomy and behaviour.

This study aims to investigate whether forest management has an effect on reproduction, haematological parameters and blood parasites of breeding Siberian tits Poecile cinctus. Birds breeding in heavily managed forests had significantly higher heterophil and lower lymphocyte concentrations and a higher heterophil/lymphocyte (H/L) ratio than those breeding in moderately managed forests. Although this suggests the increased level of physiological stress in Siberian tits breeding in heavily managed forests, reproductive parameters of the birds did not differ between the two habitats. Nestlings in moderately managed forests had higher total leukocyte and lymphocyte counts than nestlings in heavily managed habitat. The total count of parasites and Leucocytozoon majoris was significantly higher near streams, while the count of Plasmodium circumflexum was higher both near streams and lakes. Although blood parasites were detected in the blood of 80% adult birds, this study did not reveal any parasite-related effects on haematological parameters.

Species that are locally abundant tend to be more widespread than species that are locally rare. However, the opposite relationship has recently been observed with extensive abundance data for Finnish butterflies collected by voluntary lepidopterist. We were concerned about the suitability of these data for studying the distribution—abundance relationship in Finnish butterflies. Thus, we reviewed Finnish mark—recapture studies that report data for butterfly density. In these data, we found a positive density—distribution relationship for butterflies. Our study supports the conclusion that the positive distribution—abundance relationship is a general pattern for butterflies.