No genetic evidence of sex-biased dispersal in a lekking bird, the capercaillie (Tetrao urogallus)

Sex-biased dispersal is often connected to the mating behaviour of the species. Even if patterns of natal dispersal are reasonably well documented for monogamous birds, only a few data are available for polygynous and especially lekking species. We investigated the dispersal of the capercaillie (Tetrao urogallus) by examining sex-specific gene flow among the leks. Genetic information was extracted using nuclear and mitochondrial molecular markers for sexed faecal samples and analysed by novel Bayesian statistical methods. Contrary to the traditional view that the males are highly philopatric and female is the dispersing sex, we found roughly equivalent gross and effective dispersal of the sexes. The level of polygamy has a strong influence on the effective population size and on the effective dispersal. The results do not support the theories that dispersal evolves solely as a result of resource competition or other advantages to males obtained through kin selection in lekking species.     

Characteristics of fresh semen of captive-bred capercaillie Tetrao urogallus L

In Poland Capercaillie (Tetrao urogallus L.) is one of the most seriously endangered grouse species. The ability of semen collection and its utilization for Capercaillie female insemination would allow overcoming some fertility problems observed in captive-bred populations and thus reduce the rate of loss of genetic diversity. The present experiment was carried out on 13 individuals: eight males were kept with females and five alone. From each male, semen was collected four times, every second day, and overall semen appearance (color, viscosity), ejaculate volume, spermatozoa concentration, motility and morphology were examined. Ejaculates suitable for artificial insemination (AI) were obtained from 11 individuals. The volume of ejaculates varied from one drop (noted as 0.010 ml) to 0.180 ml, whereas spermatozoa concentration varied from 100 × 10(6) ml(-1) to 1950 × 10(6) ml(-1). The total amount of live spermatozoa for males kept with females varied from 82.0 to 98.3% (92.9% on average) and among them, from 38.7 to 82.0% were morphologically normal (67.6% on average), whereas for solitary males these values were the following: from 93.7 to 98.7 of total live (96.3% on average) and from 45.0 to 85.3% live normal cells (65.7% on average). No significant group effect was observed for above traits. Semen from males kept with females contained significantly (P<0.01) fewer cells with bulb head (12.2% vs. 21.6%), but higher numbers of bent neck spermatozoa (3.0 vs. 2.1%) and with other deformities (10.0 vs. 6.8%); however, for last two forms existing differences were not significant. Results obtained indicate the possibility of collecting valuable ejaculates from captive-bred Capercaillie, both kept with or without females, which makes possible the application of AI in order to increase the progeny number and gene exchange of this species across time and geographical distance.     

Impact of hand-rearing on morphology and physiology of the capercaillie (Tetrao urogallus)

Morphological and physiological disparities between 20 captive and 11 wild capercaillies were determined. Birds, their pectoral and leg muscles, hearts, livers and gizzards were weighed. The length of small intestines and caeca were measured. Haemoglobin, haematocrit, glucose, triglycerides, total protein, uric acid and thyroid hormones as well as the cytochrome c-oxidase activity of the pectoral muscle and heart were determined. The glycogen and protein contents of pectoral and leg muscles and liver were analysed. Chemical composition (water, fat, protein, ash) of muscles and liver was determined. Captive males had heavier pectoral muscles than wild ones. The result was opposite in females. Wild birds had heavier hearts, livers, and gizzards, and also longer small intestines and caeca than captive birds. The cytochrome c-oxidase activity of pectoral muscle and heart was higher in wild than in hand-reared birds. The chemical composition of livers of wild birds differed significantly from that of hand-reared capercaillies. Plasma uric acid and T(4) concentrations were higher in captive than in wild birds. The observed differences in digestive system and liver can result in diminished ability of captive birds to utilise natural food nutrients. Decreased cytochrome c-oxidase activity of hand-reared birds can affect their takeoff and flying capacity and increase their vulnerability to predation. These facts may contribute to the low survival of hand-reared birds after release.     

Seasonal variation in lek attendance and lekking behaviour by male Black Grouse Tetrao tetrix

Eleven Black Grouse Tetrao tetrix leks in the Scottish Highlands were visited at dawn once every week for a year. Apart from July and three leks which were unoccupied in winter, males visited leks throughout the year. Total numbers of males attending leks peaked in March in one study area (six leks) and in April in the second (five leks). The number of males present and the proportion of leks occupied varied seasonally. The proportion of males at leks was at a maximum in April (80% of males) when all leks were attended, with a secondary peak in September when 60% of leks had males present. Males spent the most time displaying in April. The optimal conditions for attendance were calm, dry mornings just after dawn. Most reliable counts of numbers of males were those made between the last week of March and the end of the first week of May.     

Responses by the capercaillie Tetrao urogallus, and the willow grouse Lagopus lagopus, to the green matter available in early spring

Food matter eaten in the first snowless spots early in the spring by capercaillie Tetrao urogallus and willow grouse Lagopus lagopus was studied in Finnish Forest Lapland. When the snow disappears, both species change to feeding mainly on the plants available in the snowless spots, although male capercaillie does not exploit this nutritious diet to the same extent as female capercaillie and willow grouse. Selection in favour of nitrogen and phosphorus-rich food items, i.e. Betula pubescens , male catkins Eriophorum vaginatum , flower buds, and Equisetum spp., stems and tips, seems to be characteristic especially of the female capercaillie, whose winter diet is poor in these elements. Female capercaillie also feeds on more plant species or different parts of plants at one time than willow grouse, while no differences were recorded between male and female willow grouse in the composition of their spring food. The crowberry Empetrum hermaphroditum , almost regularly produces a bountiful berry crop in northern Finland, and since it overwinters well, it represents an easy source of energy and water available almost every spring. The quality and/or the quantity of the green food matter available early in the spring may fluctuate considerably and be of importance for short-term fluctuations in the populations of these tetraonid species.     

A first test of unattended,acoustic recorders for monitoring Capercaillie Tetrao urogallus lekking activity

Capsule: Automated acoustic recording can be used as a valuable survey technique for Capercaillie Tetrao urogallus leks, improving the quality and quantity of field data for this endangered bird species. However, more development work and testing against traditional methods are needed to establish optimal working practices.

Aims: This study aims to determine whether Capercaillie vocalizations can be recognized in lek recordings, whether this can be automated using readily available software, and whether the number of calls resulting varies with location, weather conditions, date and time of day.

Methods: Unattended recording devices and semi-automated call classification software were used to record and analyse the display calls of Capercaillie at three known lek sites in Scotland over a two-week period.

Results: Capercaillie calls were successfully and rapidly identified within a data set that included the vocalizations of other bird species and environmental noise. Calls could be readily recognized to species level using a combination of unsupervised software and manual analysis. The number of calls varied by time and date, by recorder/microphone location at the lek site, and with weather conditions. This information can be used to better target future acoustic monitoring and improve the quality of existing traditional lek surveys.

Conclusion: Bioacoustic methods provide a practical and cost-effective way to determine habitat occupancy and activity levels by a vocally distinctive bird species. Following further testing alongside traditional counting methods, it could offer a significant new approach towards more effective monitoring of local population levels for Capercaillie and other species of conservation concern.     

Successful preservation of capercaillie (Tetrao urogallus L.) semen in liquid and frozen states

Experiments on semen collection and preservation were undertaken by Wroc?aw University of Environmental and Life Sciences and Forestry Wis?a, Poland to assist in the protection of the capercaillie (Tetrao urogallus L.) and to create an ex situ in vitro cryobank. Semen was collected from 11 captive-bred males, using dorsoabdominal massage. Ejaculates once obtained were diluted 3-fold at room temperature with EK diluent and then a number of them were stored at 4 °C for 18, 24, and 48 hours, while the remaining ejaculates were equilibrated with 6% dimethylacetamide and frozen by pipetting, drop-by-drop directly onto a liquid nitrogen surface. Frozen pellets were thawed at 60 °C in a water bath after 4 to 28 mo of storage. In total, 103 individually collected ejaculates (54 stored as liquid and 49 frozen in liquid nitrogen) were of appropriate value for further processing. The volume of ejaculates varied from 30 to 240 μL; spermatozoa concentration from 70 × 10⁶ mL⁻¹ to 1950 × 10⁶ mL⁻¹. The total amount of live spermatozoa in the fresh semen varied from 85.3% to 99.0%, of which from 41.1% to 85.3% were morphologically normal. Among morphologically abnormal forms, bulb-head (5.6% to 36.0%) and midpiece deformations (1.3% to 16.6%) were the most frequent. Dilution and semen storage up to 24 h at 4 °C did not affect the semen quality, as far as motility and sperm morphology are concerned. A significant (P < 0.05) decrease in total live (94.9 vs. 91.7%) and live normal cells (66.4 vs. 56.7%) was observed after 48 h. About 30% to 40% of spermatozoa remained motile. Cryopreservation significantly decreased (P < 0.05) the total number of live and live normal spermatozoa however, in relation to the fresh semen, their average content was 44.1% and 37.4%, respectively. Significant (P < 0.05) individual differences were observed in the quality of the fresh, liquid stored and the frozen-thawed semen assessed in terms of spermatozoa motility and morphology. After a single insemination with thawed semen containing 9.7 million live normal cells, 80% fertility and 100% hatchability were achieved. The obtained results indicate for the first time that there is the potential to use liquid stored and cryopreserved capercaillie semen to support conservation measures for the maintenance of genetic diversity, as well as to increase the number of reintroduced progeny of this endangered grouse species.     

Sex-specific population dynamics and demography of capercaillie (Tetrao urogallus L.) in a patchy environment

Modeling the population dynamics of patchily distributed species is a challenge, particularly when inference must be based on incomplete and small data sets such as those from most species of conservation concern. Here, we develop an open population spatial capture–recapture (SCR) model with sex-specific detection and population dynamics parameters to investigate population trend and sex-specific population dynamics of a capercaillie (Tetrao urogallus) population in Switzerland living in eight distinct forest patches totaling 22 km² within a region of 908 km² and sampled via scat collection. Our model accounts for the patchy distribution of habitat and the uncertainty introduced by collecting data only every third year, while producing sex by patch population trajectories. The estimated population trajectory was a decline of 2% per year; however, the sex specificity of the model revealed a decline in the male population only, with no evidence of decline in the female population. The decline observed in males was explained by the demography of just two of the eight patches. Our study highlights the flexibility of open population SCR models for assessing population trajectories through time and across space and emphasizes the desirability of estimating sex-stratified population trends especially in species of conservation concern.     

Increased DNA typing success for feces and feathers of capercaillie (Tetrao urogallus) and black grouse (Tetrao tetrix)

Noninvasive sampling, for example, of droppings or feathers, is a promising approach for molecular genetic studies on endangered and elusive animal species. Yet, such specimens are known for containing only minute amounts of DNA, resulting in lower typing success rates relative to analyses on fresh tissues such as muscle or blood. Furthermore, artefactual signals as well as contamination are more likely to occur when DNA is limited. To increase the reliability of DNA typing from noninvasive samples, optimized DNA extraction and polymerase chain reaction protocols were developed, taking advantage of developments in the forensic field aiming at successful molecular genetic analysis of DNA templates being low in quality and quantity. In the framework of an extensive monitoring project on population dynamics of capercaillie and black grouse in the Tyrolean Alps, feces samples and molted feathers from both species were collected. On a subset comprising about 200 specimens of either species, eight polymorphic short tandem repeat (STR) markers were analyzed to test these improved protocols. Besides optimizing DNA yields, both lowered sample consumption and reduced hands‐on time were achieved, and the rates of informative profiles amounted to 90.7% for capercaillie and 92.4% for black grouse. Similarly, high success rates had not been achieved in earlier studies and demonstrate the benefit of the improved methodology, which should be easily adaptable for use on animal species other than those studied here. The STR genotypes were not only powerful enough to discriminate among unrelated birds but also appeared fit for telling apart closely related animals, as indicated by Pi and Pi_sib values. The software package allelematch aided analysis of genotypes featuring possible dropout and drop‐in effects. Finally, a comparison between molecular genetic and morphology‐based species‐of‐origin determination revealed a high degree of concordance.     

Balancing the needs of capercaillie (Tetrao urogallus) and moose (Alces alces) in large-scale human land use

The capercaillie has been negatively affected by the loss of mature forests. However, forestry creates young plantations offering a superabundant food supply for moose. Using two spatial scales, we tested whether the landscape-level environmental requirements of the capercaillie and moose differ. We compared the spatial association between the abundances of the two species in 50-?×?50-km grids and, using a set of regression models, analyzed how it was affected by various land use variables in five regions of Finland. Both species were generally most abundant in the same grid cells. Moreover, the association between abundance and several landscape variables was very similar for both species. Forest cover had a positive impact on both species in Eastern and South-Western Finland. Only in Western Finland was the capercaillie more positively associated with older forest than the moose. Human impact variables were negatively related to both capercaillie and moose abundance in Eastern and South-Western Finland, the effect being stronger for capercaillie. In Northern Finland, human impact turned positive. Our results highlight that, on broad landscape and regional scales, we might not need to make trade-offs in management decisions concerning capercaillie and moose. While considering regional land use planning, the primary goal for both species seems to be to secure large areas of forest, preferably at a distance from human settlement.     

Temporal and spatial analyses disclose consequences of habitat fragmentation on the genetic diversity in capercaillie (Tetrao urogallus)

As a result of habitat fragmentation, the capercaillie ( Tetrao urogallus ) population in the Black Forest mountain range in southwestern Germany has declined rapidly during the last decades and now persists in patchy isolated fragments. To study the effects of fragmentation, we quantified dispersal patterns by genotyping 213 individuals in four subpopulations. We used a landscape genetics approach to analyse individual genetic variation, and despite overall low genetic structure, we found strong indications for a major boundary separating the northern part of the Black Forest area from the other subpopulations. Males and females display different gene flow patterns across the landscape. Females tend to disperse across longer distances than do males. We additionally studied the effects of the population decline on genetic diversity during the last hundred years. Although the population has dramatically declined from over 4000 to 250 males over a few decades, genetic diversity was not affected in the same way. We found two haplotypes that were present only in historic samples but microsatellite markers revealed no significant reduction in genetic diversity. Among historic samples, genetic differentiation was very low, indicating that the current genetic structure is caused by recent habitat fragmentation. We argue that inferences about reduced genetic diversity are drawn cautiously and recommend sampling over different temporal scales.     

Outdoor recreation causes effective habitat reduction in capercaillie Tetrao urogallus: a major threat for geographically restricted populations

Outdoor recreation inflicts a wide array of impacts on individual animals, many of them reflected in the avoidance of disturbed areas. The scale and spatial extent, however, at which wildlife populations are affected, are mostly unclear. Particularly in geographically isolated populations, where restricted habitat availability may preclude a relocation to undisturbed areas, effective habitat reduction may remain underestimated or even unnoticed, when animals stay in disturbed areas and only show small‐scale responses. Based on telemetry data, we investigated the spatial and seasonal effects of outdoor recreation – in relation to landscape and vegetation conditions – on western capercaillie Tetrao urogallus, considering two scales, home range and within‐home range habitat selection. We determined the distance‐thresholds up to which recreation infrastructures were avoided and estimated the extent of affected habitat for the isolated Black Forest (southwestern Germany) study population. While outdoor recreation did not affect home range selection, strong effects on habitat use within the home range were detected: distance to recreation infrastructure (hiking and cross‐country skiing trails, ski pistes) was the main determinant of habitat selection in winter; in summer, mountain bike trails and hiker's restaurants were avoided up to an average distance of 145 m (CI: 60–1092 m). Around winter‐infrastructure, relative avoidance was recorded up to 320 m (CI: 36–327 m), it was reduced, however, when dense understory provided visual cover. Of the entire population area, between 8–20% (summer) and 8–40% (winter) were affected by outdoor recreation, mainly in the high altitudes. Even without evident large‐scale shifts in species distribution, local‐scale avoidance of outdoor recreation can substantially contribute to effective habitat reduction. Based on our results we recommend a general reduction in recreation infrastructure density in key habitats, the establishment of undisturbed wildlife refuges with a diameter of at least 800 m, as well as enhancing visual protection by maintaining a strip of dense understory along trails.     

Reintroducing capercaillie (Tetrao urogallus) into southern Scotland: identification of minimum viable populations at potential release sites

Capercaillie (Tetrao urogallus) populations are declining in western parts of their range, including Scotland. It has been proposed that their numbers, and the extent of their range in Scotland be increased to reduce the risk of a second extinction in the UK. The feasibility of a reintroduction of capercaillie to coniferous plantations in southern Scotland was assessed by undertaking a population viability analysis. Following a review of capercaillie ecology and habitat requirements, VORTEX population simulation software was used to identify a minimum viable population (MVP). From this the minimum dynamic area of suitable habitat required in order to support such a MVP was then calculated. It was estimated that a minimum of 60 individuals would be required in approximately 5000ha of habitat in order for the population to have a >0.95 probability of surviving for 50 years. Supplementation of populations with two unrelated individuals every five years reduced the MVP to ten individuals. Further simulations were run in order to establish the sensitivity of the model to changes in three key parameters. Assessment of areas of suitable habitat identified two potential release sites, Wauchope and Newcastleton forests, in southern Scotland. Some practical considerations relating to management of a release population are outlined. It was concluded that an appropriately planned and resourced reintroduction was feasible.     

The abnormal conduct of capercaillies Tetrao urogallus.

The frequency, behavior, and testosterone levels of deviant capercaillies were studied in southern Finland. Roughly 1% of the population was estimated to behave abnormally. Deviant males display and show threatening behavior toward not only humans, but also attacked stuffed capercaillie males and without hesitation copulated with a stuffed female. Deviant females appear tame and crouch in front of humans, but avoid males. The testosterone level in deviant males was about five times higher than that of normal displaying males. The origin of this striking phenomenon is still unclear, although it must be connected with display. Two, though not mutually exclusive, proximate mechanisms for the development of this abnormal behavior are presented: anomalous sex hormone concentrations and incorrect sexual imprinting. The ultimate reason for the apparent increase in numbers of deviant capercaillies is probably logging which diminishes populations and, thereby, favors the spreading of abnormal behavior.     

Ranging behaviour of little bustard males, Tetrax tetrax, in the lekking grounds

We investigated the ranging behaviour during the breeding season of 18 radiotracked little bustard (Tetrax tetrax) males, a disperse-lekking species inhabiting the cereal pseudo-steppes. The average kernel 95% home range was 60±50 ha and the average cluster 85% area was 17±17 ha. Range structure was as relevant as home range size for explaining the variation in the ranging behaviour of males, which could be partially explained by age, habitat quality and site. Ranging behaviour varied from males defending small and concentrated home ranges with high habitat quality, to males holding larger home ranges composed by several arenas. Our results suggest that social dominance and resource availability may affect ranging behaviour of males during the breeding season. Also, mating systems constraints may play a role on the use of space of males within the lekking ground. The ranging behaviour of a given male may be determined by a tendency to reduce and concentrate the home range as age and social status increase, and several fine-tuning mechanisms adjusting the ranging behaviour to the prevailing environmental or social factors on a given site and year.     

Habitat characteristics of Capercaillie Tetrao urogallus display grounds in southeastern Norway

Habitat composition of 39 capercaillie Tetrao urogallus display grounds was compared with available and unused habitats in two coniferous forest areas in southeastern Norway. Macro-habitat was described with respect to forest successional stage and topography. Micro-habitat was described with respect to microtopography, plant association, and forest stand structure. Totally, 28 variables were measured. A pronounced macro-habitat preference was found for elevated areas with forests older than 60-70 years. Micro–habitat composition varied considerably. However, a slight but significant preference was found for heterogeneous, open-spaced understory, and for visibility of more than 30 m. Suitable micro-habitats were abundant, and distribution of display grounds were mainly limited by macro-habitat characteristics, i.e. elevated, old forest areas.     

Winter tourism increases stress hormone levels in the Capercaillie Tetrao urogallus

Montane and alpine habitats in Europe remained relatively undisturbed until the beginning of the last century. Today, outdoor recreation activities are a major economic factor in alpine regions. Many tourism areas coincide with winter habitats of shy and endangered species. The Western Capercaillie Tetrao urogallus has suffered from rapid population declines during recent decades over much of its range. In central Europe, many Capercaillie are exposed to intensive human recreation activities in their habitats, which may contribute to this decline. However, little is known about their susceptibility to human recreation activities. This study assessed whether human recreation in winter evokes physiological stress responses in several populations of Capercaillie. During two winters, we sampled 1130 Capercaillie droppings in Germany and Switzerland of populations at various distances from winter recreation activities and measured concentrations of faecal corticosterone metabolites. Capercaillie in relatively dense and homogeneous mountain forests dominated by Norway Spruce Picea abies showed markedly increased stress hormone levels closer to locations with winter recreation activity. However, this physiological response to human recreation was not detectable in forests dominated by various pine species and a heterogeneous structure. Capercaillie may be particularly sensitive to recreation because any factor affecting their fine‐tuned physiological and behavioural adaptations to survive under harsh winter conditions may lead to harmful fitness costs.     

Habitat partitioning in endangered Cantabrian capercaillie Tetrao urogallus cantabricus

The endangered Cantabrian capercaillie (Tetrao urogallus cantabricus) lives at the southern edge of tetraonids’ distribution range, in entirely deciduous forests. Its conservation planning has been always lek-centred. There is very little information about the specific habitat requirements of hens and broods, even though reproductive success appears to be a limiting factor. We analysed summer surveys from 1997 to 2004, carried out to estimate the reproductive success of the population. We compared the habitat characteristics at different spatial scales of hens with broods, broodless hens, and cocks in summer, with the better known spring habitat in display areas. Summer habitat showed higher proportion of open areas and was associated with more rugged zones at moderate spatial scales (78 ha) than spring habitat at display areas. Cocks and hens showed summer habitat partitioning; hens were associated with higher proportions of open and shrubby habitats. Furthermore, broodless hens preferred areas with higher slope variability than the display and summer areas preferred by cocks. These differences may reflect the sexual dimorphism of the species in reproductive role, energetic demands and conspicuousness. At larger spatial scales a previously developed habitat suitability model performed well to predict good brood-rearing areas. Hens with broods were located in the best-preserved areas in the range, mainly characterized by higher proportion of forest cover at a large (50 km²) scale. We suggest that these characteristics indicate refuge habitats where Cantabrian capercaillie can still breed successfully.