Ranging and nesting behaviour of the dormouse, Muscardinus avellanarius, in diverse low-growing woodland

Thirty-four dormice ( Muscardinus avellanarius ) were radiotracked to investigate their movements and use of space. They were found to be entirely arboreal and would make considerable detours rather than cross open ground. Their activities centred upon particular feeding sites which changed as the summer progressed. The animals did not range widely and normally were not found more than 100 m from their nest. Males travelled more widely than females. Male home ranges overlapped those of females but not each other. Dormice mostly chose to use artificial nestboxes; their few natural nest sites were mostly in the high shrub canopy, not in the low shrubs where dormouse nests have previously been reported. The implications of these findings are discussed in relation to conservation management of woodlands and the vulnerability of dormouse populations.     

Summer mortality in the hazel dormouse (Muscardinus avellanarius) and its effect on population dynamics

In the period 2000–2012, 38.3 % of 950 marked overwintered hazel dormice (Muscardinus avellanarius) were not recaptured at a study site in Lithuania in autumn. As adult dormice are sedentary, it is presumed that those dormice not recaptured died between late April and August. The highest total number of dormice captured for the last time was recorded in May and the lowest in August. The total summer mortality was significantly higher in females (42.5 %) than in males (34.6 %), but it did not depend on dormouse age or body weight. Tawny owl (Strix aluco) is the main known dormouse predator in Lithuania, and likely, it has the highest impact on summer mortality of M. avellanarius. Over the years, the total summer mortality of adult dormice ranged from 27 % to 52 %. The increased summer mortality resulted in decreased total dormouse population density and particularly decreased density of adult females in summer. Decreased densities led to more intensive breeding in the dormouse population, specifically breeding by young-of-the-year females, a pattern that is not common for this species. The number of breeding cases by young-of-the-year females was inversely related to the density of adult overwintered females in summer and to the number of breeding cases of these females. Breeding by young-of-the-year females was the main factor in the restoration of decreased population density in summer. Lithuanian populations of M. avellanarius are unique in their high proportion of breeding cases by young-of-the-year females amongst all populations investigated in the entire species distributional range.     

Nestbox provisioning in a rural population of Eurasian Kestrels: breeding performance,nest predation and parasitism

The breeding biology of the Eurasian Kestrel Falco tinnunculusin nestboxes in farmland was studied to test for differences between artificial and natural sites. We report on the direct effect of nestbox provisioning on some life-history traits and how nestbox use affects nest predation and parasitism. Five types of nest-sites were available: nestboxes on poles and trees (artificial sites), stick nests on trees, stick nests on pylons and holes in buildings (‘natural’ sites). The Kestrel population increased from 23 pairs in 1993 (prior to nestbox installation) to 55 in 1998 as nestboxes were provided. In general, pairs breeding in trees started to lay later than those nesting in nestboxes on poles or in building holes, but this difference was probably associated with habitat quality rather than nest type. Differences in clutch size were found between nest-sites in some years, and were associated with laying date and, probably, with variation in territory quality. Using only data from successful nests, pairs breeding in nestboxes produce more fledglings than those in building holes or pylons. The frequency of nest predation was higher in natural sites than in nestboxes. The number of fledglings from pairs breeding in nestboxes was higher than from those breeding in old stick nests in trees when all nests were considered. Nestbox provisioning had no effect on the occurrence of the ectoparasite Carnus hemapterus, but chicks from nestboxes showed higher intensity of infection. Our results suggest that nestbox provisioning increases reproductive success and the frequency of nest predation or intensity of parasite infestation in Kestrels.     

Long-term common dormouse monitoring: effects of forest management on abundance

The common dormouse (Muscardinus avellanarius) is a species included in Annex IV of the Habitat Directive and red-listed in many European countries. Monitoring of M. avellanarius is implemented in several countries using different methods. In Lithuania, regular control of standard bird nestboxes and marking of all dormice caught were used during 1984–1990 and 1999–2007. Nestboxes were spaced in a grid system at 50 m intervals in an area of 60 ha. Monitoring of the M. avellanarius population was carried out in a managed forest with varying levels of human activity occurring in most parts of the forest (felling of all understorey, selective felling of trees, clear felling, etc.). During the entire study period, the average density of the population was comparatively low (about 1 ind./ha in spring and 3 ind./ha in autumn), but stable and without substantial fluctuations in spite of considerable human activity. The forestry management operations that were used in different parts of the forest over different years had only temporary and localised negative effects on the abundance of M. avellanarius, and did not influence the whole population substantially. The spacing of nestboxes in a grid system in a large forest area increased the level of accuracy with which the monitoring scheme reflected the population status. This enabled both the state of the entire population of M. avellanarius and temporary changes in abundance in selected smaller plots to be tracked. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Using Long-Term Volunteer Records to Examine Dormouse ( Muscardinus avellanarius ) Nestbox Selection

Within ecology, there are unanswered questions about species-habitat interactions, which could potentially be resolved by a pragmatic analysis of a long-term volunteer-collected dataset. Here, we analysed 18 years of volunteer-collected data from a UK dormouse nestbox monitoring programme to determine the influence of habitat variables on nestbox choice by common dormice ( Muscardinus avellanarius ). We measured a range of habitat variables in a coppiced woodland in Gloucestershire, UK, and analysed these in relation to dormouse nestbox occupancy records (by dormice, other small mammals, and birds) collected by volunteers. While some characteristics of the woodland had changed over 18 years, simple transformation of the data and interpretation of the results indicated that the dataset was informative. Using stepwise regressions, multiple environmental and ecological factors were found to determine nestbox selection. Distance from the edge of the wood was the most influential (this did not change over 18 years), with boxes in the woodland interior being selected preferentially. There was a significant negative relationship with the presence of ferns (indicative of damp shady conditions). The presence of oak (a long-lived species), and the clumped structural complexity of the canopy were also important factors in the final model. There was no evidence of competition between dormice and birds or other mammals. The results provide greater understanding of artificial dormouse nest-site requirements and indicate that, in terms of habitat selection, long-term volunteer-collected datasets contribute usefully to understanding the requirements of species with an important conservation status.     

Current nest box designs may not be optimal for the larger forest dormice: Pre‐hibernation increase in body mass might lead to sampling bias in ecological data

1. Biologists commonly use nest boxes to study small arboreal mammals, including the forest dormouse (Dryomys nitedula). Hibernating dormouse species often experience pronounced seasonal variations in body mass, which might lead to sampling biases if it is not taken into account when designing nest boxes. In my study of the forest dormouse, I noticed that the entrance hole of nest boxes had been gnawed. I hypothesized that this behavior was exhibited by the individual dormice of higher body mass, who were unable to pass through the entrance holes.
2. To test my hypothesis, I categorized the individual dormice present inside nest boxes based on their body mass and then compared the seasonal body mass dynamics with the timing of the gnawing behavior. I also compared nest box occupancy by the forest dormouse before and after the gnawing behavior.
3. Interestingly, I found that the gnawing behavior was displayed exclusively when part of the dormouse population increased considerably in body mass, which supports my hypothesis. Additionally, nest box occupancy decreased significantly from 20% before to 4.6% after the gnawing behavior.
4. I suggest that researchers include nest boxes with entrance holes larger than 4 cm in future studies of the forest dormouse to prevent the possible exclusion of the conspecifics that have higher body mass before hibernation. This type of sampling bias might also concern studies of other species, such as the fat dormouse, that similarly show pronounced seasonal variations in body mass. I recommend that biologists consider the seasonal body mass dynamics of the target species when designing nest boxes to minimize bias in ecological data and improve management actions.

     

Nest box use by woodland dormice (Graphiurus murinus): the influence of life cycle and nest box placement

The use of nest boxes by the woodland dormouse, Graphiurus murinus, was investigated over a 13-month period in a riverine forest of the Great Fish River Reserve, South Africa. We predicted that some characteristics of nest box placement would affect nest box use and that the seasonal pattern of nest box use would be linked to the species' life cycle and physiological and socioecological characteristics. Generalized linear models indicated that the time since nest box installation and nest box height above ground positively affected the frequency and intensity of nest box use. Male and female dormice, as well as adults and juveniles, did not differ in the number of nest boxes used and equally occupied individual nest boxes. The percentage of nest boxes used peaked during spring and summer (breeding period) and dropped during winter (hibernation). However, whereas significantly more males were caught during the mating season (spring), the number of females occupying nest boxes was constant during the year. As female dormice successfully bred in the nest boxes, the observed sexual patterns suggest that (artificial) nest sites represent an important resource for females, whereas females seem to constitute the main resource for males, as predicted by the socioecological model.     

Social Dominance among Male Meadow Voles is Inversely Related to Reproductive Success

Intrasexual selection can occur through direct aggressive interactions between males for access to females. We tested the relationship between social dominance and male reproductive success among meadow voles, Microtus pennsylvanicus. Dominance ranks of wild‐caught males were determined using neutral arena trials, with the winner of two of three trials considered dominant. These males were then released into field enclosures and allowed to visit females housed in nestboxes for 8 wk, and males’ home range sizes were determined using weekly grid trapping. Male reproductive success was determined using molecular paternity analysis (six microsatellite primers) for all pups born during the field experiment. Males with higher dominance ranks had larger home ranges. However, male dominance rank was not predictive of the number of total visits to females’ nestboxes or the number of visits to each male's most frequently visited nestbox. Males that made more visits to nestboxes sired more litters. Males that had higher dominance ranks sired fewer litters. These results suggest that there is a reproductive disadvantage to having higher dominance rank among male meadow voles.     

Flea burden and its influence on nest selection and use in Dryomys nitedula Pallas, 1778

Since dormice usually use natural tree hollows or artificial nest boxes as nest sites and these nests are reused from 1 year to another, the present study investigated how the parasite loads from old nests affected the behaviour of the forest dormouse Dryomys nitedula Pallas, 1778. Dormice were subjected to three different experiments: 1. They were given the choice of a nest box infected with ectoparasites and a new unused nest box; 2. Dormice were given the choice of a treated (uninfected) previously used nest boxes and previously used nest box that was infected; and 3. Using infrared motion sensor cameras, we tested weather they preferred to avoid nest boxes when only infected nests were available. The results revealed that the females with pups are pickier when choosing the nursery site. These preferred empty nest boxes or nest boxes with treated nests instead of the infested ones. However, non-breeding adults and sub-adults showed indifference to the flea infestation of the nest.     

Context‐dependent conservation of the cavity‐nesting European Roller

To maximize the effectiveness of conservation interventions, it is crucial to have an understanding of how intraspecific variation determines the relative importance of potential limiting factors. For bird populations, limiting factors include nest‐site availability and foraging resources, with the former often addressed through the provision of artificial nestboxes. However, the effectiveness of artificial nestboxes depends on the relative importance of nest‐site vs. foraging resource limitations. Here, we investigate factors driving variation in breeding density, nestbox occupation and productivity in two contrasting study populations of the European Roller Coracias garrulus, an obligate cavity‐nesting insectivorous bird. Breeding density was more than four times higher at the French study site than at the Latvian site, and there was a positive correlation between breeding density (at the 1‐km² scale) and nest‐site availability in France, whereas there was a positive correlation between breeding density and foraging resource availability in Latvia. Similarly, the probability of a nestbox being occupied increased with predicted foraging resource availability in Latvia but not in France. We detected no positive effect of foraging resource availability on productivity at either site, with most variation in breeding success driven by temporal effects: a seasonal decline in France and strong interannual fluctuations in Latvia. Our results indicate that the factors limiting local breeding density can vary across a species' range, resulting in different conservation priorities. Nestbox provisioning is a sufficient short‐term conservation solution at our French study site, where foraging resources are typically abundant, but in Latvia the restoration of foraging habitat may be more important.     

Green nesting material has a function in mate attraction in the European starling

The function of fresh green nest material has long been debated. It has been suggested that it reduces the number of ectoparasites in nests and on nestlings (nest protection hypothesis), or is used by males to signal condition and paternal quality (male quality hypothesis) or is used as a sexually selected ornament to attract females (courtship hypothesis). We simultaneously tested these three hypotheses in the European starling, Sturnus vulgaris, in the field. Green material was carried by male starlings only, and mainly during nest building. It was not used to reduce ectoparasites. Males nesting in nestboxes that were experimentally contaminated with ectoparasites did not carry more green nest material than males nesting in control boxes, and experimental removal and addition of green material had no effect on the number of ectoparasites on the nestlings or on their body mass. Furthermore, the amount of green material carried into a nestbox was not associated with male body mass, paternal incubation attendance or nestling food provisioning. There is two-fold experimental evidence that males use green plant material to attract mates. First, removal of greenery resulted in a significantly lower percentage of nestboxes containing a clutch than the control or addition treatment. Second, unpaired male starlings sang more and carried more greenery into a nestbox when a caged female was positioned adjacent to the nestbox than when a caged male or an empty cage was present. Paired males, when subjected to the same experimental design, did not respond.     

Demographic consequences of nestbox use for Red‐footed Falcons Falco vespertinus in Central Asia

Nestbox programmes are frequently implemented for the conservation of cavity‐nesting birds, but their effectiveness is rarely evaluated in comparison with birds not using nestboxes. In the European Palaearctic, Red‐footed Falcon Falco vespertinus populations are both of high conservation concern and are strongly associated with nestbox programmes in heavily managed landscapes. We used a 21‐year monitoring dataset collected on 753 nesting attempts by Red‐footed Falcons in unmanaged natural or semi‐natural habitats to provide basic information on this poorly known species; to evaluate long‐term demographic trends within this population; and to evaluate response of demographic parameters of Red‐footed Falcons to environmental factors including use of nestboxes. We observed significant differences among years in laying date, offspring loss and numbers of fledglings produced, but not in egg production. Of these four parameters, offspring loss and, to a lesser extent, number of fledglings exhibited directional trends over time. Variation in laying date and in numbers of eggs were not well explained by any one model of environmental factors, but instead by combinations of models, each with informative terms for nest type. Nevertheless, laying in nestboxes occurred 2.10 ± 0.70 days earlier than in natural nests. In contrast, variation in both offspring loss and numbers of fledglings produced were fairly well explained by a single model including terms for nest type, nest location and an interaction between the two parameters (65 and 81% model weights, respectively), with highest offspring loss in nestboxes on forest edges. Because, for other species, earlier laying dates are associated with more fit individuals, this interaction highlighted a possible ecological trap, whereby birds using nestboxes on forest edges lay eggs earlier but suffer greater offspring loss and produce lower numbers of fledglings than do those in other nesting settings. If nestboxes increase offspring loss for Red‐footed Falcons in heavily managed landscapes where populations are at greater risk, or for the many other species of rare or endangered birds supported by nestbox programmes, these processes could have important demographic and conservation consequences.     

Provision of nestboxes raises the breeding density of Great Tits Parus major equally in coniferous and deciduous woodland

Nestbox provision is a technique used to increase nest-site availability for secondary cavity-nesting birds. However, little is known about the demographic consequences of nestbox provision in different habitat types. To assess how nestbox provision affects the density of hole-nesting birds simultaneously in two contrasting habitats, we compared the breeding density of Great Tits along transects without nestboxes with that in transects where nestboxes were provided. Although the initial density of breeders was considerably higher in the deciduous habitat than in the coniferous habitat, provision of nestboxes increased density by a similar number of additional pairs in each habitat type. Thus, the provision of nestboxes in managed coniferous forests may be as effective in increasing the breeding opportunities of cavity nesters as in deciduous stands. Moreover, previous research showed that pairs in deciduous habitat with nestboxes have consistently lower breeding success than those in coniferous habitat with nestboxes. It is possible that the addition of nestboxes in the preferred habitat increased density to such an extent that density-dependent effects became apparent.     

Temporal patterning of external stimuli and reproductive behaviour in female budgerigars

The role of stimuli from the nestbox, the male and breeding females in regulating the course of reproductive development in female budgerigars is examined. When females were paired with males but deprived of nestboxes no development of the overy, oviduct or brood patch occurred. Females visually and auditorily isolated from males entered their nestboxes, but fewer (8 per cent) laid eggs than females paired with males (75 per cent). More females (50 per cent) hearing only breeding females laid eggs than females (8 per cent) isolated from breeding females and males. The differential effects of the stimuli are discussed.     

Frequency and demographic parameters of white-tipped common dormiceMuscardinus avellanarius

Out of 1154 marked common dormiceMuscardinus avellanarius (Linnaeus, 1758), 219 animals (19.0%) had white tail tips at Vilkaraistis forest (Moletai district, east Lithuania) in 1984–1993. The extent of white tail-tip varied from a slight tuft to a notable 22 mm length of white hair in the tail tip. In this population white-tipped individuals represented, on average, 25.7% among juvenile females, 24.9% among adult females, 13.4% among juvenile males, and 15.7% among adult males. White-tipped females were significantly more frequent than males, both in juveniles and in adults. The share of white-tipped dormice fluctuated in different years from 12.5% to 25.6% among adult dormice, and from 9.2% to 28.3% among juveniles. The percentage of white-tipped dormice among juveniles in different years was directly proportional to population density in autumn. There was no clear difference or trend in the mortality rate in white-tipped versus normal dormice. The contribution of white-tipped females to population reproduction was relatively lower than that of normal females: only 18.4% out of all registered breeding cases (n=212) were due to white-tipped females.     

The value of nestboxes in the conservation of Eurasian Rollers Coracias garrulus in southern Spain

The installation of nestboxes is a widely used conservation measure for enhancing habitat suitability for cavity‐nesting birds wherever natural holes are scarce. However, nestboxes may attract birds to unsuitable breeding places or induce a non‐random distribution of individuals in relation to their qualities. We investigated the factors influencing nestbox selection and the quality of breeding territories for the globally near‐threatened Eurasian Roller in a semi‐arid area of southeast of Spain over a 3‐year period. Rollers preferentially used exposed nestboxes that were placed far from highly modified areas. However, breeding success was significantly lower in exposed nestboxes. Early breeders preferred nestboxes oriented to the northwest over any other orientation. Exposure had opposite effects on nestbox use and breeding success, suggesting that nestboxes installed in exposed sites could function as ecological traps for Rollers.     

Effect of nestbox type on occupancy and breeding biology of Tree Sparrows Passer montanus in central Spain

Avian life-history studies are often conducted on populations nesting in nestboxes. However, the type of nestbox used is a potentially confounding variable, as each model shows specific characteristics. In recent decades, a new commercial model of artificial nestbox made of woodcrete, a mixture of sawdust and additives, has become popular owing to its better protection against predators compared with the classic wooden design. We assess the effect of nestbox type on the breeding ecology of Tree Sparrows Passer montanus , focusing on their thermal properties, an influential factor in nestbox selection. Occupancy rates and reproductive parameters of Tree Sparrows were compared between birds breeding in woodcrete and wooden nestboxes over 5 years. Woodcrete nestboxes had a higher occupancy rate and birds breeding in them had earlier clutches, a shorter incubation period and more reproductive attempts per season than birds nesting in wooden boxes. Clutch size and nestling condition did not differ between nestbox types, but reproductive success was higher in woodcrete nestboxes. The higher temperature in woodcrete nestboxes (1.5 °C higher on average) might explain these differences. Such differences may bias results obtained in comparative studies where more than one nestbox type is used.     

Characteristics of Garden Dormice That Contribute to Their Capacity as Reservoirs for Lyme Disease Spirochetes

To describe the contribution of garden dormice to the epizootiology of Lyme disease, we compared their reservoir capacity for these pathogens to that of other sympatric hosts. Garden dormice are trapped most abundantly during early spring and again during midsummer, when their offspring forage. They are closely associated with moist forests. Garden dormice serve as hosts to nymphal ticks far more frequently than do other small mammals. Spirochetal infection is most prevalent in dormice, and many more larval ticks acquire infection in the course of feeding on these than on other rodents in the study site. Mature dormice appear to contribute more infections to the vector population than juveniles do. Replete larval ticks generally detach while their dormouse hosts remain within their nests. The population of garden dormice contributes five- to sevenfold more infections to the vector population than the mouse population does. Their competence, nymphal feeding density, and preference for a tick-permissive habitat combine to favor garden dormice over other putative reservoir hosts of Lyme disease spirochetes.     

Effects of nestboxes on the breeding biology of Southern House Wrens Troglodytes aedon bonariae in the southern temperate zone

Nestboxes are known to increase clutch size, enhance breeding success and affect the social mating system of several cavity nesters. Although in recent years various cavity nesters have been studied in nestboxes in South America, the effects of boxes on the biology of the study species are unknown. We evaluated the effects of nestboxes on the breeding biology and social mating system of Southern House Wrens Troglodytes aedon bonariae by comparing birds breeding in nestboxes and tree cavities in two cattle ranches in Buenos Aires Province, Argentina. Southern House Wrens nesting in boxes had higher breeding success but, contrary to studies on the temperate zone, we did not find differences in clutch size between Wrens breeding in nestboxes and tree cavities. The main causes of nest failure in tree cavities were nest predation and flooding of the cavity (70 and 23% of the failures, respectively) while in nestboxes predation and desertion were the most important causes of failure (38 and 34% of the failures, respectively). The social mating system of Southern House Wrens is monogamy with biparental care, and neither was affected by the boxes. Males did not attract secondary females to additional nestboxes; however, nestboxes are safer breeding sites than tree cavities, and females seemed to prefer males with nestboxes on their territory. These results suggest that nest quality alone might be not enough for secondary females to accept polygyny.