The accuracy of the territory-mapping technique for estimating the abundance of densely breeding Hawfinches was tested in an old and unfragmented lime-oak-hombeam forest in the Białowieża National Park, E Poland. Hawfinch numbers estimated from counts of the whole bird community carried out with the application of the standards of the improved mapping technique were compared with seven-year data on the bird's true numbers, which are known from parallel intensive nest searches and persistent tracking of the movements of pairs. In a forest with a dense population of Hawfinches the mapping technique underestimated their numbers by 20% in years of moderate density and by 35% during high-density years. Even though the underestimation was negatively correlated with the true density of Hawfinches, the figures obtained by both methods reflected year-to-year changes in a similar way. An improvement in mapping data is achievable either by closer attention being paid to the species during standard visits (the best ones for surveying it), or post factum by the introduction of a correction factor into the mapping-technique figures.
We surveyed the prevalence of quill mites in wild passerines captured in Wielkopolski National Park, Poland. A total of 438 birds of 12 species were mist-netted during three consecutive spring seasons from 2006–2008. Eight bird species were infested with syringophilid mites: Erithacus rubecula (L.) (index of prevalence, IP = 16.2%), Turdrus merula L. (IP = 22.4%), T. philomelos Brehm (IP = 10.5%), Fringilla coelebs L. (IP = 36.2%), Coccothraustes coccothraustes (L.) (IP = 7.4%), Sturnus vulgaris L. (IP = 53.6%), Sylvia atricapilla (L.) (IP = 6.1%) and Troglodytes troglodytes (L.) (IP = 7.1%). In four cases, multiple infestation was observed, where one bird species was parasitized by 2–3 species of quill mites occupying separate niches in the plumage of the host.
Long-term observations (1991-2002) have shown that Hawfinches breed throughout the extensive Białowieża Forest; they are only slightly less numerous in the forest interior than at its edge. Population size, habitat and nest sites were studied in two plots in the species-optimal habitat (continuous oak-lime-hornbeam old-growth). The true breeding density there was 4.0-8.4, reaching as much as 15.2 p/10 ha in some years, while, according to the combined territory-mapping method for the same period, it was, on average, 5.8 pairs/10 ha in oak-lime-hornbeam, 3.3 pairs/10 ha in riparian ash-alder, but less than 0.5 pairs/10 ha in mixed coniferous-deciduous or young deciduous stands (marginal habitats for this species). Being among the most numerous species in the Białowieża Forest bird community, Hawfinches hold small nesting territories that are sometimes loosely grouped. Nests are built at an average height of 18.1 (7-34) m in the tree canopy. Hornbeams are the preferred tree species for nesting in the oak-lime-hornbeam stands (also clumps of mistletoe in the continental maple), while black alders in the riparian woodland. Originally, the Hawfinch must have been a species of old, high forests. Its recent nesting elsewhere — low in bushes or, preferably, along woodland edges — is likely to be a secondarily acquired trait; it could also be due to a bias — Hawfinch nests are more easily discovered in such localities.
We used a nested PCR protocol to examine the genetic diversity of cytochrome b (cyt b) lineages from blood parasites of the genera Plasmodium and Haemoproteus in birds in Bulgaria. In total, 460 birds of 43 species and 14 families (mostly passerines) were examined for the presence of infections. Of them, 267 were recognised as infected with haemosporidian parasites. Mixed infections were recorded in 24 individuals (9%). Besides the 24 individuals with mix infections, 114 (43%) were positive for Plasmodium spp. and 129 (48%) for Haemoproteus spp. We identified 52 genetic lineages of haemosporidian parasites: 38 of Haemoproteus and 14 of Plasmodium. Twelve new cyt b lineages of Haemoproteus were recorded; they occurred in the following hosts: grey-faced woodpecker (Picus canus), golden oriole (Oriolus oriolus), jay (Garrulus glandarius), barred warbler (Sylvia nisoria), song thrush (Turdus philomelos), spotted flycatcher (Muscicapa striata), spanish sparrow (Passer hispaniolensis), hawfinch (Coccothraustes coccothraustes), and cirl bunting (Emberiza cirlus). We also detected 22 new host records for previously known lineages. The most common lineage was SGS1 (Plasmodium relictum), which had a total prevalence of 14% and occurred in 8 host species belonging to 5 families. Three of the cyt b lineages of genus Haemoproteus (DURB1, DURB2 and SYNIS2) showed more than 5% divergence from all described morphologically lineages. These lineages probably represent at least 2 different morphospecies which remains to be identified.