설악산국립공원지역에서 고도별 조류군집의 특성

Bird populations in upland spruce plantations in northern Britain

Breeding success of four titmice breeding in forests was investigated during 1962–2001. Three of them, Coal Tit Parus ater, Willow Tit Parus montanus and Marsh Tit Parus palustris have shown declining population trends in the annual monitoring of bird species in Sweden. The fourth species, the Crested Tit Parus cristatus, has shown a stable population size. Two of the declining species, Marsh Tit and Coal Tit, had the largest broods during the most recent decade and significantly positive trends in brood sizes during the investigated period, whereas the Willow Tit and Crested Tit had stable brood sizes. Our study indicates that the declines of the Coal Tit, Willow Tit and Marsh Tit populations in Sweden cannot be explained by changes in brood size, number of dead nestlings or number of un-hatched eggs. The stable population size of Crested Tit might be explained by its habit of breeding early in the season, which has become more pronounced during the most recent decades, probably in order to match breeding to the earlier spring arrival nowadays.

Gosler, A. G. & King, J. R. 1989. Asexually dimorphic plumage character in the Coal Tit Parus ater with notes on the Marsh Tit Parus palustris. Ring. & Migr. 10: 53–57. Although Coal Tits may be sexed during the breeding season on the presence or absence of a brood patch or cloacal protruberance, no plumage differences have been noted previously, so that sexing has not been possible outside this period. We present observations of Coal Tits trapped at two sites in southern England which indicate that the bib of this species is strongly dimorphic in shape, extent and colour intensity.

Wildlife monitoring performed by volunteer personnel may suffer from bias with regard to their habitat use. Such errors can lead to erroneous population estimates, evidently influencing both management programmes and research that are based on the monitoring. We used a dataset on hunters’ habitat use in forest while searching for black grouse (Tetrao tetrix) and capercaillie (Tetrao urogallus) to test whether hunters’ utilisation of the habitat was independent of that of grouse or if it corresponded to the grouse habitat preference. Twenty volunteer hunters with dogs registered their tracks and all observations of capercaillie and black grouse in Ostfold County, Norway, during August 2003 and 2004. We performed an ecological niche factor analysis (ENFA) and a K-select analysis with respect to hunters’ selection for habitat, described with ecogeographical variables related to forest stand characteristics, as well as the habitat preference of the observed grouse, conditional on the habitat utilisation of the hunters. Individual ENFA on the hunter's tracks revealed large variation in the habitat preferences of the hunters. The K-select indicated few overall patterns in the habitat characteristics of grouse observations, conditional on the hunters selected habitat. Accordingly, the results indicate that hunters’ observation of grouse prior to the hunt may give indicators of changes in grouse density unbiased by habitat preference due to the large between-hunter variation in habitat preference, given that a sufficient number of hunters is used. This suggests that such monitoring programmes can provide information about fluctuations in grouse population sizes valuable for both the management and research of forest grouse species.

I studied predator‐prey relationships between goshawk Accipiter gentilis and four species of forest grouse (Tetraonidae) in northern Finland during 1988–1998. The main purpose of my study was to evaluate the impact of goshawk predation and its possible effect on multiannual cycling patterns in grouse numbers. Theoretically specialist predators should tend to cause stable‐limit cycles in prey populations if there is a time‐lag in the predator's response to prey density and the prey species should be most affected at low densities. Four grouse species, willow grouse Lagopus lagopus, black grouse Tetrao tetrix, capercaillie Tetrao urogallus and hazel grouse Bonasa bonasia, form the main food of the goshawk in boreal forests in northern Finland. Grouse constituted >40% of the goshawk's diet during the breeding season. The impact of predation by breeding goshawks on grouse varied depending on grouse species within 7–32% during the breeding season. Losses were highest for willow grouse and lowest for capercaillie. On average, goshawks took 6% of grouse chicks. On an annual basis breeding goshawks took 2–31% of the August grouse population. The goshawk's share of the total mortality in grouse was also species related. The most reliable estimates were found for black grouse of which 35% were removed and for hazel grouse of which 40% were removed. Goshawks are relatively specialised on forest grouse in northern boreal forests as was demonstrated by a weak functional response of the hawks to changes in grouse density. Breeding goshawks showed no numerical response to changes in grouse density but the production of young tended to lag one year behind black grouse density. The predation rate of goshawks was inversely density dependent on changes in grouse density, which may have had a destabilising effect on the grouse populations. A positive relationship existed between summer predation on willow grouse and changes in the population the previous year.

Sexual and seasonal differences in mortality in the Black Grouse Tetrao tetrix L. were studied by radio-tracking 53 hens for 3051 bird-days in spring and summer, and 54 cocks for 3906 birds-days during spring to winter in Swedish boreal forest. The mortality rate of hens during spring and summer was 0.35 but had a sharp peak during egg laying and incubation. Goshawk Accipiter gentilis L. predation was the major known cause of death (12 of 17 kills). Outside the breeding season mortality seemed to be low.

Unique skin microbial communities have been shaped by the harsh climatic conditions in high-altitude areas, such as intense ultraviolet radiation and low oxygen concentration. However, it is unknown whether high altitude contributes to shaping common microbiota inhabiting the skin across different mammals. The skin microbial communities of humans and horses living in high-altitude (Tibetan) and low-altitude areas were analyzed using full-length 16S rRNA sequencing technology. Alpha diversity differed between high- and low-altitude groups (p < 0.01). Skin microbial community composition also differed between high- and low-altitude areas (p < 0.05). Some of the common taxa present in the skin of humans and horses in high-altitude areas were identified as extreme microorganisms capable of adapting to the harsh high-altitude environment. Five bacterial taxa, including the genera Sphingomonas, Brevundimonas, and Kocuria, as well as the species Acinetobacter guillouiae and Arboricoccus pini, were significantly enriched (p < 0.01) on the skin of both humans and horses in high-altitude areas. Meanwhile, some taxa enriched on the skin surface at the same altitude showed preferences for mammalian species. Acinetobacter johnsonii, Anaerococcus nagyae, and Anaerococcus octavius were significantly enriched (p < 0.05) in the skin of humans at both high and low altitudes, whereas Acinetobacter pseudolwoffii and Armatimonas rosea, Archangium gephyra and Acinetobacter lwoffii were significantly enriched (p < 0.05) in the skin of horses at both high and low altitudes. In the network analyses, a positive correlation (p < 0.01) was shown between the skin taxa enriched in high-altitude areas and each other, while a negative correlation (p < 0.01) was found between the skin microorganisms enriched in high-altitude areas and those enriched in low-altitude areas. Overall, our findings indicate that high-altitude extreme environments drive convergent evolution of skin microbiota across mammals, reflecting the joint effects of environmental selection and host-related filtering on community assembly. This cross-species comparison provides a framework for understanding skin microbiome responses to extreme environments in plateau mammals.

Most of forest birds have the characteristics for habitat selection. The purpose of this study is to clarify the vegetation structure in breeding area of Siberian rubythroat (Luscinia calliope). In Daecheongbong peak, Mt. Seoraksan national park, South Korea from May to August, 2001, breeding population of Siberian rubythroat and the dominant species in breeding area of Siberian rubythroat (Luscinia calliope) were surveyed by line transect method along the ridge in the Daecheongbong peak area. Number of individuals and location of song posts were observed and recorded. According to the survey results, the study area was classified into high, middle and low density areas. Those birds selected the forest area of dominant species for Erman’s birch and dwarf Siberian pine as habitat and preferred the shrubs area with the lower height and higher coverage.

We studied the effects of cattle on selection of home ranges and habitats by female mule deer (Odocoileus hemionus) on summer range in the Sierra Nevada, California. Three grazing levels (no grazing, moderate grazing, and heavy grazing) were imposed on 3 fenced range units over 3 years. Habitat selection by 13 radio-collared female mule deer was estimated each summer; habitat selection by radio-collared cattle was estimated at the 2 grazing levels. In the absence of grazing, meadow-riparian habitat comprised a greater proportion of deer home ranges than during grazing. During moderate and heavy grazing, a greater proportion of montane shrub habitat was included within deer home ranges than when ungrazed. Within home ranges, deer preferred meadow-riparian habitat at all grazing levels, whereas aspen (Populus tremuloides) habitat was preferred only during no grazing. Deer preference for meadow-riparian habitat declined over the summer, more so with cattle grazing. Cattle also preferred meadow-riparian and aspen habitats. The greatest effect of cattle on habitat selection by female mule deer occurred during late summer with heavy grazing when forage and cover were at a minimum in preferred habitats. Female mule deer shifted habitat use by reducing their use of habitats preferred by cattle and increasing their use of habitats avoided by cattle. These results were consistent with expectations of competition and habitat selection theory. Abstract: We studied the effects of cattle on selection of home ranges and habitats by female mule deer (Odocoileus hemionus) on summer range in the Sierra Nevada, California. Three grazing levels (no grazing, moderate grazing, and heavy grazing) were imposed on 3 fenced range units over 3 years. Habitat selection by 13 radio-collared female mule deer was estimated each summer; habitat selection by radio-collared cattle was estimated at the 2 grazing levels. In the absence of grazing, meadow-riparian habitat comprised a greater proportion of deer home ranges than during grazing. During moderate and heavy grazing, a greater proportion of montane shrub habitat was included within deer home ranges than when ungrazed. Within home ranges, deer preferred meadow-riparian habitat at all grazing levels, whereas aspen (Populus tremuloides) habitat was preferred only during no grazing. Deer preference for meadow-riparian habitat declined over the summer, more so with cattle grazing. Cattle also preferred meadow-riparian and aspen habitats. The greatest effect of cattle on habitat selection by female mule deer occurred during late summer with heavy grazing when forage and cover were at a minimum in preferred habitats. Female mule deer shifted habitat use by reducing their use of habitats preferred by cattle and increasing their use of habitats avoided by cattle. These results were consistent with expectations of competition and habitat selection theory.

Distributions of birds in lowland agricultural landscapes of England and Wales: How distinctive are bird communities of hedgerows and woodland?

The Black Grouse Tetrao tetrix is primarily a lekking species, although in some populations solitary display is also common. We analysed data from a 25-year-long survey of an increasing Black Grouse population in the western Italian Alps in order to test whether the numbers of males adopting different tactics conformed to patterns expected, based on the hypothesis that dominant birds occupy the leks and solitary displaying birds are subordinate, and that the tendency for birds to be excluded from leks increases with lek size. Four predictions were made to test this hypothesis: (1) the proportion of solitary males would increase as the overall population increases, (2) there would be a threshold at which there is little or no increase in the size of the lekking population, but continued increase in the population of solitary displaying birds, (3) available lek habitat would be occupied prior to an increase in solitary displaying males, and (4) there would be an increase in the use of less preferred habitat by solitary displaying males as the total population increases. Population trends varied according to display status, in that the lekking population reached an apparent threshold while the number of solitary males continued to increase, and there was an expansion of the range of solitary males into higher altitudes in years when the population was larger. However, there was no increase in the proportion of solitary males as the total population increased. Furthermore, there was no suggestion that suitable lek habitat was limiting, as the number of leks and the mean size of those leks continued to increase throughout the study period. Although two predictions were supported, the precise patterns of trends, and results of additional analyses, suggested that solitary display is more likely to be an alternative rather than a subordinate tactic. Several factors may promote this apparent dual display tactic in Black Grouse, but habitat structure in this and other Alpine populations is likely to be a key influence.

In Perthshire (Scotland), Black Grouse Tetrao tetrix broods less than 3 weeks old preferred herb‐rich grassy flushes with Bog Myrtle Myrica gale, whereas in the northern Pennines (England), all broods were found on grass‐dominated moorland or enclosed rough grazing habitats chiefly of grass and rushes. In both areas, broods used habitats with taller vegetation that had more invertebrates, particularly moth caterpillars and sawfly larvae (Sym‐phyta, Hymenoptera). Within preferred habitats, broods were found in vegetation containing more flies (Diptera), plant bugs (Hemiptera) and ichneumon flies (Hymenoptera) than at randomly chosen sites. The main hatch of Black Grouse chicks in Perthshire coincided with the peak availability of moth caterpillars preferred by chicks. Broods in the Pennines hatched 1 week later than those in Scotland, and this later breeding in the south may be an adaptation to utilize the later peak biomass of sawfly larvae, the chief insect prey there. Data collected for Capercaillie Tetrao urogallus suggest a similar degree of synchronization between their peak hatch and the availability of moth caterpillars on Bilberry Vaccinium myrtillus.

Recent studies of animal habitat selection are inferring more detail regarding the behavioural mechanisms involved, like functional responses and familiarity effects. Changes in animals’ use or selection of a habitat type with changing availability are commonly interpreted as a functional response in habitat preference. Studies of familiarity inferred preference for familiar locations from selection for previously visited locations after accounting for habitat‐related preference. We simulated movement paths on discrete landscapes using random walk models with known habitat selection behaviour to assess emergent properties related to habitat selection in the context of functional and familiarity responses. The behavioural interpretation of functional responses relies on the relationship between habitat use and preference. Unfortunately, this relationship is not unique and depends upon the habitat choice mechanism: habitat use can be proportional to preference or proportional to availability (called respectively, hierarchical and simultaneous choice). We found that when the analytical method did not match the choice mechanism, strong functional responses were observed in habitat selection, even though habitat preference was kept constant. Therefore, functional responses need to be discussed in the context of an animal's habitat choice mechanism. In the absence of familiarity‐related preference, we found no familiarity effect while accounting for all habitat variables. However, when habitat models were incomplete (e.g. lack of information about resources and habitats in the landscape) – as in all field studies – spurious preference for familiar locations arose. Our study aids the interpretation of behavioural mechanisms in habitat selection studies, but also calls for a more thorough study of the approaches used to infer behavioural mechanisms in habitat selection studies.

We integrated GPS and accelerometer data to examine habitat selection and energy expenditure patterns across the diel cycle in Strix varia (Barred Owls), addressing a critical gap in wildlife research that often overlooks activity during the “inactive” phase. Owls in Baton Rouge, Louisiana, selected forests with tall canopies and open understories, particularly in affluent neighborhoods, supporting the “luxury effect” in urban biodiversity. Nocturnal home ranges were larger (31.8 ha) compared to diurnal home ranges (8.9 ha), indicating broader habitat use at night. The total area of preferred nocturnal habitat was 33% of the Baton Rouge study area, whereas preferred diurnal habitat comprised only 5%. Energy expenditure was inversely related to preference in nocturnal home ranges but increased with preference in diurnal home ranges. Our models were validated using independent data from Clemson, South Carolina, supporting the robustness of our analysis and revealing generalities in owl habitat selection across these regions. This research contributes to a deeper understanding of urban ecology, highlighting habitat components preferred by owls and possibly other forest-dwelling species. It emphasizes the difference in nocturnal and diurnal home range sizes, the scarcity of daytime refuges for S. varia in urban landscapes, and the variation in energy expenditure in preferred habitats. Our findings advocate for urban designs that accommodate wildlife activity throughout the day and night, and highlight the positive correlation between preferred owl habitat and affluent neighborhoods, underscoring the need for equitable distribution of green spaces to foster biodiversity across socioeconomic gradients. These insights will help develop strategies to enhance the ecological value of urban environments and the conservation of S. varia and associated forest-dwelling species in rapidly urbanizing areas.

We studied the role of early developed phenotypic characters associated to body size (i.e., tarsus, wing, and tail length) together with body mass in the determination of the winter residence and recruitment of juvenile coal tits (Parus ater) captured after the post-fledging period. From morphological variables and by means of multivariate analysis, we obtained an index of overall body size, an index of relative tarsus length, and an index of body condition independent of body size. Tarsus index and to a lesser extent condition index, but not overall body-size index, were associated to recruitment. The tarsus index was also positively associated with the probability of individuals becoming residents within the study area during winter, which turned out to be the key factor determining recruitment of juveniles in our coal tit population. However, effects of the tarsus index on juvenile recruitment appeared to be a complex function acting at different stages during the individual’s first winter. The tarsus index seemed to be indirectly related to recruitment by favouring winter residence in large individuals, but among resident individuals recruitment was low for very large ones, resulting in individuals of intermediate tarsus lengths having overall higher recruitment rates. The body-condition index also influenced recruitment indirectly by favouring residence in individuals with intermediate values. Our results suggest that conditions during early growth of phenotypic characters may have an influence on individual fitness extending after the post-fledging period by influencing social factors crucial to recruitment such as winter residence.