The influence of high nestbox density on the common dormouseMuscardinus avellanarius population

The response of common dormouseMuscardinus avellanarius Linnaeus, 1758 population to availability of nest sites was studied by manipulating the nestbox grid and ring-marking dormice. Abundance of adult dormice more than doubled in the 25 × 25 m nestbox grid in comparison to the 50 × 50 m grid, as a result of increased nestbox density from four to 16 boxes/ha. This effect already became apparent in the first year after additional nestboxes were made available and resulted from dormouse immigration, mostly from adjacent areas without nestboxes. In the second and third years, the number of two-year-old and older resident dormice, which had their home ranges in this plot, increased considerably. The average size of dormouse home range decreased by approximately half both in males and females in the 25 × 25 m grid compared to the 50 × 50 m grid. The proportion of breeding adult females did not differ between the two grids in spite of different adult dormouse density. Shortage of secure nest sites was a limiting factor for the common dormouse population abundance in the forest where natural tree hollows were absent, and high nestbox density increased environmental carrying capacity.     

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.     

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.     

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, but Not Egg, Fidelity in a Territorial Salamander

Egg recognition and subsequent egg brooding are costly forms of parental investment in many species of vertebrates. Life history factors, such as coloniality or risk of brood parasitism, may constrain egg recognition in vertebrates. Female red-backed salamanders ( Plethodon cinereus ) from my study site are territorial and do not share nest sites with other females. They are terrestrial and neither they nor their eggs are likely to be displaced by environmental factors such as flooding. I experimentally tested, in the laboratory, the hypothesis that female red-backed salamanders can discriminate between their own eggs and the eggs of unfamiliar females. Each female was allowed to move about a test chamber containing two clutches of eggs, one clutch with which it was found in the forest and one that had been found with a distant female. Most females remained with one clutch of eggs, which they brooded during the entire observation period. However, they did not significantly prefer to brood their own eggs over the eggs of another female. In a corollary field experiment, I tested whether brooding females that were displaced 1 m from their nest sites would return to their territories and commence brooding behaviour within 3 d. All 10 displaced females returned to their own nest within this time period and were found brooding their eggs. Because female red-backed salamanders at my study site do not tend to share nest sites with other females and because their eggs remain in stationary nests, selection may not have favoured egg recognition. However, the results suggest that female salamanders indirectly recognize their own eggs by actively recognizing their territorial nest sites.     

Social and Thermal Cues Influence Nest‐site Selection in a Nocturnal Gecko,Oedura lesueurii

In oviparous species lacking parental care, successful reproduction depends on females selecting nest sites that facilitate embryonic development. Such sites may be limited in the environment, which can lead to multiple females using the same nest site simultaneously. However, there are several alternative explanations for communal nesting, including natal homing, predator satiation, and adaptive benefits to offspring. We used laboratory experiments to evaluate three hypotheses about nest‐site selection in velvet geckos (Oedura lesueurii), which often nest communally. We investigated whether the trend to nest communally is influenced by the following: (1) evidence of previous nesting (hatched eggshells); (2) body size; and/or (3) thermal regimes. When given the choice, females laid their eggs in shelters containing hatched eggshells rather than in empty shelters, and this was not influenced by body size. Females selected nest sites that were cooler than their own mean selected body temperatures, suggesting that thermal requirements of their developing embryos could outweigh their own thermoregulatory preferences. Field observations of natal homing and high predation rates on gravid females suggest that imprinting on nest sites and/or predator swamping also play roles in communal nesting. Collectively, our results suggest that female velvet geckos use multiple cues to select appropriate nest sites, and hence that multiple mechanisms result in communal nesting behavior in this species.     

Should I Stay or Should I go? The Influence of Handling by Researchers on Den use in an Arboreal Nocturnal Rodent

Understanding how animals respond to disturbance by investigators is essential for a fair assessment of the presence of bias in routinely used research protocols. It is also an essential prerequisite for anyone interested in animal welfare and ethically sound research. Here, we utilize an automatic logging system to monitor nest box use by PIT‐tagged edible dormice, Glis glis, after standard handling procedures applied during a regular nest‐box monitoring programme. The edible dormouse is an arboreal nocturnal rodent that relies on tree hollows as daytime den sites. We assessed the effect of disturbance on dormice in two ways: whether it affected the decision of an individual to stay in the same den site for a subsequent day and whether it affected the timing of the individual's nocturnal emergence from the den site. We found handling had a strong negative effect on short‐term den use. In addition, females and sexually active individuals were more likely to spend the following day in the nest box. Individuals that had left the den site after our handling returned to them after an average of 4 d. Handling did not have a significant effect on the period of absence, but reproductively active animals returned on average after 3 d, while reproductively quiescent animals returned after more than 5 d. Manipulation did not have a significant effect on the initiation of nocturnal activity. Our study suggests that disturbance by investigators may modify certain aspects of animal behaviour, but this effect is likely to be short term and does not appear to impair the efficacy of routinely practiced capture‐mark‐recapture field protocols.     

Factors affecting the duration of nest defense and reproductive lifespan of female sockeye salmon, Oncorhynchus nerka

Reproductive success of female animals is often affected by a combination of fecundity and parental care. In female salmonid fishes, acquisition of nest (redd) sites and prevention of their use by other females are critical to reproductive success. These factors are particularly important for stocks that spawn at high densities. Body size is positively correlated with fecundity and egg size, and has been hypothesized to control the outcome of intrasexual competition and longevity. We tested this hypothesis by evaluating the influences of body size, intrasexual aggression and arrival date on duration and success of redd guarding by female sockeye salmon, Oncorhynchus nerka, in a small Alaskan creek. Contrary to the hypothesis, larger females guarded their redds no longer than smaller females, and did not live as long in the stream. Aggression was not related to body size or overall longevity but was positively correlated with residence period on the redd. Females that entered the creek earlier lived longer, spent longer on their redds, and spent more time guarding their redds after spawning than females that entered the creek later. However, despite their longevity, early-arriving fish were more likely to have their redds reused by another female because they died before all the females had selected redd sites. The small average body size in this stock is consistent with weak selection for large size, and with our evidence that size provided little if any advantage in nest guarding.     

Hunting mode and success of African Peregrines Falco peregrinus minor,does nesting habitat quality affect foraging efficiency?

Peregrine Falcon Falco peregrmus hunting behaviour was studied at nest-sites in three areas of South Africa over eight years. In Africa, resident Peregrines are mostly restricted to high cliffs, possibly because these structures provide optimal conditions for hunting. This hypothesis is examined in terms of the influence of nest-site quality, particularly cliff height, on foraging efficiency. Foraging mode varied considerably between sites, and males foraged more actively than females but there was little variation in the design of hunts between sexes, seasons or study areas. Individually, Peregrines spent 30–50% of the day on or near the nest cliff. On average, about 0.5 hunts were recorded per hour of observation. Foraging mode was not correlated with cliff height or elevation above the surrounding terrain, but Peregrine pairs occupying higher cliffs achieved greater hunting success rates. Most hunts were initiated from elevated perches on the nest cliff, and perch hunts were more successful than strikes made from the air. Success was highest in strikes at doves and small passerines, and over habitats with moderate cover. The height difference between Peregrine and prey at the start of a hunt positively and significantly affected hunting success. Overall, Peregrines were relatively sedentary and made extensive use of the nesting habitat as a foraging area. High nest cliffs contributed to foraging success by providing perch-hunting falcons with an effective height advantage over their prey.     

Nest Site Selection by Greater Sage-Grouse in Mono County,California

ABSTRACT Loss of nesting habitat is believed to be a factor in the decline of greater sage-grouse (Centrocercus urophasianus) throughout its range. Few data are available for sage-grouse in Mono County, California, USA, in the most southwestern portion of the species’ range. We studied habitat selection of nesting sage-grouse in Mono County, California, from 2003 to 2005 by capturing and radiotracking females to identify nesting locations. We sampled vegetation at nest sites and randomly selected sites within 200 m of nests and within each of 5 subareas within Mono County. Nest sites were characterized by 42.4 ± 1.3% (x̄ ± SE) shrub canopy cover, 10.5 ± 1.0 cm residual grass height, and 2.7 ± 1.0% residual grass cover. Shrub cover was the only variable found to differentiate nest sites from randomly selected sites. Unlike some other studies, we did not find understory vegetation to be important for selecting nest sites. Mean shrub cover was 38.7 ± 1.5% at random sites within 200 m of nests and 33.6 ± 1.6% at random sites at the approximate scale of home ranges, indicating that nesting females selected nesting areas that contained denser shrubs than their home range, and nest sites that contained greater shrub cover than the vicinity immediately surrounding nests. Our results suggest that managers should consider managing for greater shrub cover in Mono County than what is currently called for in other parts of sage-grouse range and that management for sage-grouse habitat may need to be tied more closely to local conditions.     

Footprint tunnels are effective for detecting dormouse species

Glirids are arboreal rodents that are difficult to monitor due to their nocturnal activity and their relatively low density. We compared results from footprint tunnels with those from two other monitoring methods (nest boxes and nesting tubes) for three dormouse species in an occupancy framework. Footprint tunnels performed better than the other two methods for the hazel dormouse Muscardinus avellanarius and the edible dormouse Glis glis, and were the only method which detected the garden dormouse Eliomys quercinus. Our findings provide evidence to support the effectiveness of footprint tunnels in monitoring the occurrence of dormouse species in comparison with other methods.     

Intraspecific competition and the maintenance of monogamy in tree swallows

Intraspecific competition for access to breeding resources maylimit male mating success typically monogamous birds. We examinedthe potential for intraspecific competition to limit polygynyin tree swallows at Beaverhill Lake, Alberta, Canada. In thispopulation, polygynous males raisedmore fledglings than monogamousmales, and there was little or no cost to females from nestingpolygynously. Under these conditions one might expect polygynyto be more common than that observed(8% of males). We foundthat females were most aggressive toward conspecific intrudersearly in the breeding season. This aggression was associatedwith (1) females settling farther apart than expected underrandom settlement, (2) later settlement by secondary than bymonogamous females, and (3) no relationship between female settlementdate and male territory size instead of the negative correlationexpected if females settled randomly without competition. Earlyin the season, males also settled farther apart than expectedif they had settled randomly, and among males with two or morenest boxes on their territory, males with widely separated nestboxes were more likely to be polygynous. Monogamy is probablythe most common pairing association in this population becauseintraspecific competition for nest sites prevents most malesfrom gaining a territory with nest sites far enough apart topermit two females to breed without one female excluding theother. Females appeared to be defending an area surroundingtheir nest box to limit nest usurpation or intraspecific broodparasitism, rather than to limit any loss of male parental carefrom polygyny.     

Brood parasitism,female condition and clutch reduction in the common eider Somateria mollisima

Conspecific brood parasitism (CBP) is an alternative reproductive tactic found in many animals with parental care. Parasitizing females lay eggs in the nests of other females (hosts) of the same species, which incubate and raise both their own and the foreign offspring. The causes and consequences of CBP are debated. Using albumen fingerprinting of eggs for accurately detecting parasitism, we here analyse its relation to female condition and clutch size in High Arctic common eiders Somateria mollissima borealis. Among 166 clutches in a Svalbard colony, 31 (19%) contained eggs from more than one female, and 40 of 670 eggs (6%) were parasitic. In 6 cases an active nest with egg(s) was taken over by another female. Many suitable nest sites were unoccupied, indicating that CBP and nest takeover are reproductive tactics, not only consequences of nest site shortage. Similarity in body mass between female categories suggests that condition does not determine whether a nesting female becomes parasitised. There was no evidence of low condition in parasites: egg size was similar in hosts and parasites, and parasitism was equally frequent early and late in the laying season. Meta‐analysis of this and 3 other eider studies shows that there is a cost of being parasitised in this precocial species: host females laid on average 7% fewer eggs than other females.     

Nest as an extended phenotype signal of female quality in the great reed warbler

Extended phenotypes with signalling function are mostly restricted to animal taxa that use construction behaviour during courtship displays. However, they can be used also as post‐mating signals of mate quality, allowing individuals to obtain reliable information about their partners. Nest size may have such a signalling function and a lot of indirect evidence supports this view. However, direct evidence based on an experimental approach is still widely missing. Here we test the role of nest size in post‐mating signalling of mate quality in the great reed warbler Acrocephalus arundinaceus, a passerine with female‐restricted nest‐building behaviour. Based on observational data, clutch size, nestling weight, brood size and fledglings’ propensity to return to their natal site positively correlated with nest size. Moreover, we experimentally enlarged great reed warbler nests to investigate whether this manipulation affects male investment in feeding. We found that males fed their nestlings significantly more intensively on enlarged nests than those on control nests. This suggests that nest size in this species serves as a signal of female quality or willingness to invest in reproduction and that it pays males to enhance their feeding effort according to this signal. Thus, we provide convincing evidence that animal communication takes place through the extended phenotypes and that post‐mating signalling of quality is not restricted only to males, but may function equally well in females.     

Climate,landscape, habitat,and woodland management associations with hazel dormouse Muscardinus avellanarius population status

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Spatial organization of the fat dormouse (Glis glis) in an oak-hornbeam forest during the mating and post-mating season

Home range (HR) size and overlap, movements, and nest site use of fat dormice Glis glis (Linnaeus, 1766) were studied by live-trapping and radiotracking in the Bialowieza Forest in north-eastern Poland. The study was conducted during a mast year of oak Quercus robur (2001) and hornbeam Carpinus betulus (2002). Average HR size measured by 100% minimum convex polygons varied from 3.6 to 7.0 ha in males and from 0.55 to 0.76 ha in females. HR size in males was significantly larger in the hornbeam mast year than in the oak mast year, which was probably due to the lower energy value of hornbeam mast. Males had significantly larger HRs and used more nest sites than females. In contrast to females, HRs of males overlapped extensively. In the mating season, core areas of males overlapped significantly more and they shared their core areas with more males than in the post-mating season. During the mating season, males were found to share nest sites with other males or with a single female. Additionally, groups of 2–3 males were observed aggregating around a female during the mating season. Our data suggest that fat dormice have a promiscuous mating system where the females are territorial, and the non-territorial males directly compete for access to receptive females during the mating season.     

Mate preference for multiple cues: interplay between male and nest size in the sand goby, Pomatoschistus minutus

Female mating preferences are often based on more than one cue.In empirical studies, however, different mate choice cues aretypically treated separately ignoring their possible interactions.In the current work, we studied how male body size and sizeof the male's nest jointly affect mate preferences of femalesand gobies, Pomatoschistus minutus. The females were givena binary choice between males that differed either in body sizeor size of their nest or both. We found that neither body sizenor size of the nest alone affected male attractiveness, buttogether these 2 cues had a significant effect. Specifically,large males were more popular among females when they had alarge nest than when they occupied a small nest. The resultssuggest that if interaction effects between multiple mate choicecues are not considered, there is a danger of ignoring or underestimatingthe importance of these cues in sexual selection by female choice.     

Effects of site fidelity and breeding performance on mate retention in a short‐lived passerine,the tree swallow Thachycineta bicolor

We studied the relationship among re‐mating, site fidelity and breeding performance in the tree swallow Tachycineta bicolor using 16 y of data on reproductive biology in a population breeding in nest boxes near Ithaca, New York. Of 217 pairs for which both members survived the non‐breeding season, 76% mated with a new partner and 24% reunited with their previous mate. Pairs did not increase their breeding success by breeding together for more than one breeding season. Males produced fewer fledglings after breeding with a new partner, but females neither increased nor decreased their success when breeding with a new mate. Females who bred with a new partner were younger than females that reunited with their previous mates, and they were more likely to move to a different nest box. Males that bred with a new mate were of similar age to males that reunited, and they did not move more often. The probability of breeding with a new partner was better predicted by female age than by previous breeding success, suggesting that re‐mating was not strongly affected by past breeding performance. Because younger females change breeding sites more frequently than do older females and females that mated with a new partner were younger than females that reunited with their previous mates, we suggest that the tendency of tree swallows to change partners between years is a by‐product of lower site fidelity of younger females rather than a strategy for increasing breeding success.     

Selection of nest sites by a hole-nesting duck, the Goldeneye Bucephala clangula

Nest site preferences were examined for a population of Goldeneye Ducks breeding in nest boxes in Värmland, central Sweden. Some nest boxes were occupied more often than others even if females returning to the same nest box were excluded from the analysis. Nest boxes located higher up trees were occupied more often than those close to the ground and some spatial 'cluster groups' of boxes were occupied more often than others. Otherwise nest site prefernces were not related to any measured physical attributes of the boxes. Prefernces for nest boxes seemed to be based mainly on a tendency for females to select those that had been occupied by other females in the preceding year, especially if they had bred successfully. As a result of this, the occupancy of nest boxes was not random over years but rather progressed in a series of runs; a period of consecutive years in which a box was occupied was followed by a period of years in which it was empty.
There were reproductive consequences for these prefernces in that females occupying preferred boxes were less likely to lose their clutch to a predator. These females also bred earlier in the year and produced larger clutches and broods than females breeding in other boxes.     

Changes in sexual selection resulting from novel habitat use in the sand goby

Resource availability may determine local breeding systems and may also vary locally between different habitats, affecting the way individuals distribute themselves between these habitats. For nest-breeding fishes, nest site availability is a crucial resource that has been found to affect local sexual selection regimes and thus breeding systems. In this study, we compared the availability and size distribution of nest sites and their consequences for habitat preference, fish distributions and the breeding system in sand gobies ( Pomatoschistus minutus ) breeding in two different habitats. The usual breeding sites of sand gobies are shallow sandy beaches, but here we report their breeding in a novel environment, on rocky bottoms. We found obvious differences between the two habitats. The density of occupied nests was nearly 50 times higher in rock habitat than on sand bottoms. However, competition for nest sites was stronger on sand; nearly all natural nest sites found were in use and empty nest sites were occupied at a much higher rate on sand than in rock habitat. In addition to the numerical differences, nests were larger and contained more eggs in rock habitat than in sand habitat. Moreover, we found significant habitat-specific differences in fish size distribution. The intensity of intrasexual competition as a result of the degree of nest site availability explains the observed patterns within the habitats, but not between them. These habitat-related differences are better explained by the larger average size of nests on rocky bottoms. The effect of nest size on habitat preference was confirmed experimentally by laboratory experiments. When nest size did not differ between the habitats, gobies originating in the two environments showed an equal preference for the sand habitat.