Boxing for biodiversity: evaluation of an artificially created decaying wood habitat

Many saproxylic species are threatened in Europe because of habitat decline. Hollow trees represent an important habitat for saproxylic species. Artificial habitats may need to be created to maintain or increase the amount of habitat due to natural habitat decline. This study investigated the extent to which saproxylic beetles use artificial habitats in wooden boxes. The boxes were placed at various distances (0–1800 m) from known biodiversity hotspots with hollow oaks and studied over 10 years. Boxes were mainly filled with oak saw dust, oak leaves, hay and lucerne flour. In total, 2170 specimens of 91 saproxylic beetle species were sampled in 43 boxes. The abundance of species associated with tree hollows, wood rot and animal nests increased from the fourth to the final year, but species richness declined for all groups. This study shows that wooden boxes can function as saproxylic species habitats. The artificial habitats developed into a more hollow-like environment during the decade long experiment with fewer but more abundant tree hollow specialists.     

PVC nest boxes are less at risk of occupancy by feral honey bees than timber nest boxes and natural hollows

Feral European Honey Bee (Apis mellifera) has been identified as a potential nest competitor for Australian hollow nesting species, but few studies have investigated the impact of feral honey bee competition on Threatened species. Our study used data from Glossy Black‐cockatoo (Calyptorhynchus lathami halmaturinus) nests on Kangaroo Island, monitored and managed over an 11‐year period, and found 12% of nests became occupied by feral honey bees during that period. Our results indicate that feral honey bees were less likely to occupy nest boxes made of PVC (5%) compared with wooden nest boxes (24%) or natural hollows in Eucalyptus trees (14%). The removal of feral honey bee hives from nests is a priority for long‐term conservation of glossy black‐cockatoos on Kangaroo Island. We recommend that PVC nest boxes are chosen for future nesting habitat restoration, due to the more frequent use of wooden nest boxes by feral honey bees.     

Different responses of congeneric consumers to an exotic food resource: who gets the novel resource prize?

Exotic species can provide abundant food resources for native consumers, but predicting which native species will respond positively remains a challenge. We studied the foraging behavior of black-capped (Poecile atricapillus) and mountain (P. gambeli) chickadees in western Montana to compare the degree to which these congeric and syntopic consumers exploited larvae of Urophora, an exotic biological control insect living within the seedheads of the invasive forb, spotted knapweed (Centaurea stoebe). Chickadees typically forage within tree or shrub cover, whereas knapweed and hence Urophora larvae thrive in open grassland away from cover. We found that black-capped chickadees were much more likely than mountain chickadees to forage for Urophora. Black-capped chickadees strategically minimized time spent in open habitats by flying out from cover to retrieve knapweed seedheads and immediately returning to cover to extract the larvae. Black-capped chickadees also employed an atypical hovering technique nearly twice as often as their congeners did, particularly when foraging away from cover. Via this hovering technique, birds were able to gather knapweed seedheads from erect plants rather than searching for seedheads on the ground. These shifts in foraging behavior allowed black-capped chickadees to exploit Urophora larvae to a much greater degree than their congeners while minimizing exposure to a high-risk habitat, an outcome with potentially important community-wide consequences. Behavioral flexibility has been used to predict the success of invading species. We suggest that behavioral flexibility may also be used to predict how native species will respond to invasions, particularly the availability of exotic food resources.     

Evidence of accelerated beak growth associated with avian keratin disorder in black-capped chickadees (Poecile atricapillus)

We recently documented an epizootic of beak deformities in more than 2,000 Blackcapped Chickadees (Poecile atricapillus) and other wild bird species in North America. This emerging avian disease, which has been termed avian keratin disorder, results in gross overgrowth of the rhamphotheca, the outer, keratinized layer of the beak. To test the hypothesis that the beak deformities characteristic of this disorder are associated with accelerated keratin production, we measured rates of beak growth and wear in affected Black-capped Chickadees (n=16) and a control sample of unaffected chickadees (n=14) collected from south-central (61°09'-61°38'N, 149°11' -149°48'W) and interior Alaska (64°51' -64°53'N, 147°49' -147°59'W). Rates of absolute growth were 50-100% higher in affected birds than they were in control birds and exceeded records from other passerine species. These results suggest that abnormally rapid epidermal growth is the primary physical mechanism by which beak deformities develop and are maintained in affected chickadees. Although beak overgrowth typically worsened over time, differential patterns of wear influenced the severity and morphology of deformities. In some cases, the effects of accelerated keratin growth were partially mitigated by frequent breakage of rhamphothecal tips. However, mortalities occurred in 9 of 16 birds (56%) with beak deformities during the study, suggesting that avian keratin disorder results in severe health consequences for affected birds. Additional study of factors that control beak keratin production is needed to understand the pathogenesis of this debilitating disease in wild birds.     

Nest site selection and efficacy of artificial nests for breeding success of Scarlet Macaws Ara macao macao in lowland Peru

Psittacidae (parrots) have the most threatened species of any bird family in the world. Most parrots are obligate secondary cavity nesters, and can be limited in their breeding success by the availability and quality of nest hollows. However, nesting opportunities for parrots can be increased by provision of artificial nest boxes. The Tambopata Macaw Project has been studying the breeding ecology and natural history of the Scarlet Macaw Ara macao macao in the south-eastern Peruvian Amazon for over 20 years by monitoring natural nest hollows and two types of artificial nest (wooden and PVC). We present data for breeding success in natural and artificial nests over 12 consecutive breeding seasons. The aims of this study were to: (a) determine the nesting requirements and reproductive success of breeding macaws; and, (b) compare the efficacy of the two types of artificial nests and natural nest cavities. Our data showed a high rate of reoccupation of successful nests in consecutive years and that nests in artificial and natural nests had very similar reproductive parameters. Our results indicate that artificial nest types can be used by conservation managers seeking to assist A. macao populations where nest hollows are in short supply, and that artificial nests can contribute important data to natural history studies of species where access to natural nests is limited.     

Nest preference of laying hens (Gallus gallus domesticus) and their motivation to exert themselves to gain nest access

In connection with the development of a test method for the attractiveness and appropriateness of nests for laying hens, we carried out an investigation by using a preference test and motivation measuring with the help of push doors. Hens were offered two different nest sites either consisting of a tray filled with wood shavings (litter tray) or a wooden nest box plus wood shavings (nest box). Hens were individually housed in pens (2.0 m × 2.0 m) and had free access to the nest sites until they laid their 15th egg. From that day the hens had to overcome a push door to reach the nest sites. Resistance for entrance was also increased stepwise at the door leading to the hens’ nest. The experiment ended when a hen stopped to lay in her usual nest site for four consecutive days (postexperimental period). The behaviour during the last hour before oviposition was video taped at a level of resistance of 3.5, 6.0, 7.5 and 10.0 N.The hens were categorized into nest and litter layers depending on nest choice. All but one hen pushed maximum resistances between 11.5 and 18.0 N with no differences between nest and litter layers. Behaviour did not significantly change with increasing levels of resistance, but there were significant differences between nest and litter layers. Nest layers spent more time nesting than litter layers while the latter showed a strong tendency to more exploring behaviour. For litter layers, more entries through the push door leading to their nest site and more unsuccessful pushes were detected than for nest layers. According to our results, two types of layers could be distinguished whereas the two were equally motivated to access their nest site.     

The physiology of hypothermia in the black-capped Chickadee,Parus atricapillus

Summary The shivering, body temperature, and metabolic response to stable and decreasing ambient temperature were measured in winter acclimatized Black-capped Chickadees,Parus atricapillus. Shivering activity, measured by duration and amplitude of bursts, increased curvilinearly from thermoneutral temperatures of 27°C down to 0°C. This parabolic shivering response may be a major component of the curvilinear response of metabolism to decreasing ambient temperature.Birds exposed to 0°C exhibited metabolism 32–45% lower than predicted for a 12-g homeotherm and body temperatures 10°C below the pre-experimental nocturnal body temperature. This hypothermia was not the result of a breakdown in thermoregulation, but was a controlled effort serving to reduce overnight energy expenditure. It is suggested that (1) hypothermia was achieved by decreased shivering by pectoral muscles during exposure to decreasing ambient temperatures, (2) the rate of body temperature decline was moderated by intermittent and reduced bursts during the cooling period, and (3) body temperature was maintained at a particular level during exposure to a stable low ambient temperature by intense bursts lasting one to three minutes.The physiology of hypothermia in chickadees is similar to torpor; however, chickadees did not arouse to a normal diurnal body temperature in the laboratory, and their hypothermia was not induced by inanition or prolonged exposure to cold, as reported for other species capable of torpor.     

Boxes mimicking tree hollows can help conservation of saproxylic beetles

Old hollow trees have declined in Europe and many saproxylic (i.e. wood-dwelling) invertebrates living on them are threatened. The aim of this study was to investigate to what extent artificial habitats can be exploited by saproxylic beetles. To mimic the conditions in tree hollows, we constructed wooden boxes filled with different combinations of substrates like oak saw dust, oak leaves, a dead hen (Gallus domesticus), chicken dung, lucerne flour or potatoes and placed them on tree trunks. To investigate the importance of distance from dispersal sources, we placed boxes at different distances (0–1,800 m) from three species-rich sites with high densities of hollow oaks. Over 3 years, 3,423 specimens of 105 saproxylic beetle species were caught in 47 boxes. Among beetles found in hollow oaks that were either tree-hollow species, bird nest species, or wood rot species, 70% were also found in the boxes. A dead hen added to the artificial wood mould gave a higher number of beetle specimens. The number of species associated with tree hollows in oak decreased with distance from sites with hollow oaks. In conclusion, the prospects for using artificial environments for boosting substrate availability, or to fill spatial and temporal gaps therein, for saproxylic beetles are good.     

Effect of nestbox construction and colour on the occupancy and breeding success of nesting tits Parus spp.

Capsule Breeding performance was not affected, although variation in nestbox occupancy may result from perceived differences in protection from predators and insulation properties.

Aim To assess if nestboxes of different construction and colour were occupied differently by breeding tits and affected breeding success.

Methods A total of 292 nestboxes of different construction and colour were placed in a range of habitats and their occupancy, and the clutch size, brood size and number of young fledged of the birds that used them were measured.

Results Overall 272 tit nests were included in the analysis. Although there were species-related differences in the occupancy of the different types of nestboxes, more tits nested in the boxes constructed from woodcrete (64% of nests) compared to the wooden boxes (36%). More tits nested in green (72%) rather than brown boxes (28%) and in boxes with entrance holes (68%) rather than wedges (32%). The clutch size, brood size and number of young fledged did not vary in relation to nestbox type.

Conclusion Within the parameters of the experimental design of this study, tits are more likely to nest in woodcrete boxes than in wooden boxes, and in wooden boxes that are green and have holes rather than brown boxes with wedge entrances. It is likely that the smaller internal volume, internal darkness, insulating properties and perceived protection from predation were the reasons for these differences.     

Greater hippocampal neuronal recruitment in food-storing than in non-food-storing birds

Previous research has shown heightened recruitment of new neurons to the chickadee hippocampus in the fall. The present study was conducted to determine whether heightened fall recruitment is associated with the seasonal onset of food-storing by comparing neurogenesis in chickadees and a non-food-storing species, the house sparrow. Chickadees and house sparrows were captured in the wild in fall and spring and received multiple injections of the cell birth marker bromodeoxyuridine (BrdU). Birds were held in captivity and the level of hippocampal neuron recruitment was assessed after 6 weeks. Chickadees showed significantly more hippocampal neuronal recruitment than house sparrows. We found no seasonal differences in hippocampal neuronal recruitment in either species. In chickadees and in house sparrows, one-third of new cells labeled for BrdU also expressed the mature neuronal protein, NeuN. In a region adjacent to the hippocampus, the hyperpallium apicale, we observed no significant differences in neuronal recruitment between species or between seasons. Hippocampal volume and total neuron number both were greater in spring than in fall in chickadees, but no seasonal differences were observed in house sparrows. Enhanced neuronal recruitment in the hippocampus of food-storing chickadees suggests a degree of neurogenic specialization that may be associated with the spatial memory requirements of food-storing behavior.     

Flexible responses to stage‐specific offspring threats

When caring for their young, parents must compensate for threats to offspring survival in a manner that maximizes their lifetime reproductive success. In birds, parents respond to offspring threats by altering reproductive strategies throughout the breeding attempt. Because altered reproductive strategies are costly, when threats to offspring are limited, parents should exhibit a limited response. However, it is unclear if response to offspring threat is the result of an integrated set of correlated changes throughout the breeding attempt or if responses are a flexible set of dissociable changes that are stage‐specific. We test these hypotheses in a system where house wrens (Troglodytes aedon) compete for nesting cavities with Carolina chickadees (Poecile carolinensis) by usurping and destroying their nests during the early stage of the breeding attempt (the egg stage). Due to the specificity of the house wren threat, we can test whether parental responses to an offspring threat show flexibility and stage specificity or if parental strategies are an integrated and persistent response. We monitored nests in a natural population to compare life history traits of chickadees nesting in boxes that were in the presence of house wrens to chickadees nesting in boxes that did not overlap with house wrens. Carolina chickadees that nested near house wrens laid significantly smaller clutch sizes (early change in reproductive strategy) but did not alter nestling provisioning or nestling stage length (late change in reproductive strategy), suggesting that chickadees respond in a flexible and stage‐specific manner to the threat of house wrens. By responding only when a threat is highest, parents minimize the cost of antithreat responses. Our study suggests that parents can respond in subtle and nuanced ways to offspring threats in the environment and specifically alter reproductive behaviors at the appropriate stage.     

Nest box orientation affects internal temperature and nest site selection by Tree Swallows

ABSTRACT.   Orientation of nests can influence nest microclimate, particularly temperature. However, few investigators have examined orientation preference and microclimate simultaneously. We examined the possible correlation between entrance orientation of artificial nest boxes used by Tree Swallows ( Tachycineta bicolor ) and the internal temperature of boxes. Tree Swallows showed a preference for east- and south-facing boxes, but only during the first half of the breeding season (before 1 June). During the second half of the breeding season (after 1 June), Swallows selected boxes based on availability. We found that east- and south-facing boxes were warmer than north- and west-facing boxes, but only during the first half of the breeding season when those boxes were preferred. Entrance orientation and box temperature were only correlated during the morning (06:00–12:00); the temperature of all boxes was similar during the afternoon. Our results suggest that Tree Swallows show a preference for nest boxes with a certain entrance orientation only when orientation influences microclimate, suggesting that warmer nest temperatures may provide fitness benefits.     

Renesting intervals and duration of the incubation and nestling periods of Sprague's Pipits

ABSTRACT.   Sprague's Pipits ( Anthus spragueii ) are one of the least studied birds in North America, with most information about their breeding biology based on anecdotal observations at relatively few nests. I determined the renesting intervals of female Sprague's Pipits in south-central Saskatchewan and also summarized data about incubation and nestling periods of Sprague's Pipits in Saskatchewan and Manitoba to provide more robust estimates of these life-history parameters. Two of eight radio-marked females initiated replacement clutches after failed nesting attempts, with renesting intervals of 11–13 and 15–16 d, respectively. Of 74 banded females, 3 were subsequently recaptured at later nests during the same breeding season. Nests of two of these females failed due to inclement weather and their renesting attempts were initiated 6 and 7–11 d later, respectively. The third female successfully fledged young and then initiated another nest 17 d later. The new nests of females that renested were all located less than 150 m from previous nests. Incubation and nestling periods for known-aged nests ranged from 12 to 15 d (13.4 ± 0.3 [SE], N = 9) and 11 to 14 d (12.1 ± 0.2, N = 39), respectively. Variation in the length of both incubation and nestling periods was likely a function of prolonged periods of inclement weather. More data are required to determine the extent of renesting in different habitats and the extent to which Sprague's Pipits are capable of successfully raising multiple broods in a single breeding season.     

Nest site competition between cavity nesting passerines and golden paper wasps Polistes fuscatus

Nest boxes provide sheltered nesting sites for both passerines and paper wasps. Although neither wasps nor birds appear to evict the other once one is fully established, it is unclear which is the dominant competitor at the onset of the breeding season. Using wire mesh, we excluded birds but not golden paper wasps Polistesfuscatus from alternating boxes along a transect through edge habitat in North Carolina from 2006 – 2008. If wasps dominate Carolina chickadees Poecile carolinensis and eastern bluebirds Sialia sialis during the early spring (all have similar nest initiation dates), we would expect wasps to settle in both box types at equal frequencies. However, if birds dominate wasps, we would expect wasp nests to be concentrated in “bird‐proof” boxes. We found wasps in bird‐proof boxes significantly more often than in bird‐accessible boxes, indicating that secondary‐cavity nesting birds are able to exclude wasps from available nest sites. Additionally, we found that during the period of nest initiation, birds usurp wasps more often than vice versa.     

THE SANITATION OF FISH BOXES. II. THE EFFICIENCY OF VARIOUS SANITIZERS IN THE CLEANING OF COMMERCIAL WOODEN FISH BOXES

SUMMARY: An investigation of the effect of various sanitizers, including kinds containing hypo-chlorite, formaldehyde and quaternary ammonium compounds, alone and with detergents, and of a nonionic detergent alone, on the cleanability by various methods of commercial wooden fish boxes, showed that no major reductions in viable counts greater than 99·9% could be expected; this was due presumably to the high degree of contamination of the box and the porous nature of the wood. Of the materials investigated, hypochlorite solutions containing not less than 1,000 p/m of free chlorine and the quaternary ammonium compounds in 0·1–1% concentrations were most satisfactory. The implications of these investigations, to the fish industry in particular and to the cleanability of wooden surfaces in general, are discussed.     

Septum volume and food-storing behavior are related in parids

The hippocampal formation (HF) of food-storing birds is larger than non-storing species, and the size of the HF in food-storing Black-Capped Chickadees (Poecile atricapillus) varies seasonally. We examined whether the volume of the septum, a medial forebrain structure that shares reciprocal connections with the HF, demonstrates the same species and seasonal variation as has been shown in the HF. We compared septum volume in three parid species; non-storing Blue Tits (Parus caeruleus) and Great Tits (Parus major), and food-storing Black-Capped Chickadees. We found the relative septum volume to be larger in chickadees than in the non-storing species. We also compared septum and nucleus of the diagonal band (NDB) volume of Black-Capped Chickadees at different times of the year. We found that the relative septum volume varies seasonally in food-storing birds. The volume of the NDB does not vary seasonally. Due to the observed species and seasonal variation, the septum, like the hippocampal formation of food-storing birds, may be specialized for some aspects of food-storing and spatial memory.     

The value of 'bat boxes' for attracting hollow-dependent fauna to farm forestry plantations in southeast Queensland

Summary Small artificial nest/roost boxes, originally designed for microbats, were deployed in three farm forest plantations and at one native forest site in southeast Queensland in order to assess their use by vertebrates and their contribution toward enhancing biodiversity in plantation forests through the provision of habitat. Two sites were located in a relatively 'intact' forest landscape (SF 351 and Strano) and two sites in a more 'fragmented' or 'variegated' landscape (Askham and Thomas). Twenty-four boxes were placed at each site over an area covering approximately 1.2–1.8 ha. Each site was checked from five (SF 351) to nine (Askham) times between April 1996 and November 2000. The artificial nest/roost boxes were attractive to a range of small fauna that included Feathertail Gliders ( Acrobates pygmaeus ), Sugar Gliders ( Petaurus breviceps ), Squirrel Gliders ( Petaurus norfolcensis ) and the Yellow-footed Marsupial Mouse ( Antechinus flavipes ), all of which constructed nests inside boxes. Gould's Long-eared Bats ( Nyctophilus gouldi ) used boxes primarily as roosts and maternity sites. In general, fewer animals were recorded in boxes at the two sites located within a relatively 'intact' landscape, while the highest numbers of animals were recorded in boxes in two farm forest plantations within 'variegated' landscapes. The availability of alternative natural hollows and landscape factors appear to be important determinants of the extent to which boxes are occupied. The present study indicates that the biodiversity of farm forests can be enhanced through simple habitat manipulation utilizing artificial roosting or nesting boxes.
Key words Antechinus, biodiversity, farm forestry, glider, marsupial, microbat, nest box, roost.     

The utilization of dead wood resources by woodpeckers in Britain

Dead wood is important for woodpeckers, providing foraging, roost and nest-sites. In this paper, data from long-term studies of woodpeckers and dead wood in oakwoods in southern England are used to examine the dead wood requirements of the three British resident woodpecker species. Both Great Dendrocopos major and Lesser Spotted Woodpeckers Dendrocopos minor select dead trees for nest-sites although the former is able to nest in living trees too. On the other hand a smaller fraction of Lesser Spotted Woodpecker nests are in living trees. Green Woodpecker Picus viridis shows no selection for dead nesting trees. Hence the smallest woodpecker species appears to be most dependent on dead and decaying trees for nest-sites. Great and Lesser Spotted Woodpeckers show no preference for foraging on dead trees although they both make use of dead branches on living trees. Lesser Spotted Woodpeckers forage on smaller branches higher in the tree than Great Spotted Woodpeckers. There has been a trend for increasing dead wood resources in the study woods with both dead wood on the ground and standing dead trees (snags) increasing in the last 20 years. The levels of dead wood are shown to be the result of continual processes of creation and decay. Around 0.5% of oak Quercus spp., Ash Fraxinus excelsior and Hornbeam Carpinus betulus and 3.4% of the birch Betula spp. trees die each year in the woods resulting in a continuity of new dead snags and fallen trees. There is a high turnover of standing dead snags of oak and birch with 95% and 80% annual survival, respectively. Snags are only suitable for nesting Great Spotted Woodpeckers for a few years after their creation. It is suggested that these stand and dead wood dynamics are likely to provide habitats more favourable for the Great Spotted than the Lesser Spotted Woodpecker.     

Interspecific differences in the visual system and scanning behavior of three forest passerines that form heterospecific flocks

Little is known as to how visual systems and visual behaviors vary within guilds in which species share the same micro-habitat types but use different foraging tactics. We studied different dimensions of the visual system and scanning behavior of Carolina chickadees, tufted titmice, and white-breasted nuthatches, which are tree foragers that form heterospecific flocks during the winter. All species had centro-temporally located foveae that project into the frontal part of the lateral visual field. Visual acuity was the highest in nuthatches, intermediate in titmice, and the lowest in chickadees. Chickadees and titmice had relatively wide binocular fields with a high degree of eye movement right above their short bills probably to converge their eyes while searching for food. Nuthatches had narrower binocular fields with a high degree of eye movement below their bills probably to orient the fovea toward the trunk while searching for food. Chickadees and titmice had higher scanning (e.g., head movement) rates than nuthatches probably due to their wider blind areas that limit visual coverage. The visual systems of these three species seem tuned to the visual challenges posed by the different foraging and scanning strategies that facilitate the partitioning of resources within this guild.     

Seasonal metabolic acclimatization in mountain chickadees and juniper titmice

Mountain chickadees and juniper titmice from northern Utah were examined to determine metabolic and body-composition characteristics associated with seasonal acclimatization. These species use behavioral adaptations and nocturnal hypothermia, which reduce energetic costs. These adjustments could reduce the need for extensive metabolic adjustments typically found in small passerines that overwinter in cold regions. In addition, these species live at higher altitudes, which may also decrease metabolic acclimatization found in birds. Winter birds tolerated colder test temperatures than summer birds. This improved cold tolerance was associated with an increase in maximal thermogenic capacity or summit metabolism (M(sum)). Winter M(sum) exceeded summer M(sum) by 26.1% in chickadees and 16.2% in titmice. Basal metabolic rates (BMR) were also significantly higher in winter birds compared with summer birds. Pectoralis wet muscle mass increased 33.3% in chickadees and 24.1% in titmice in winter and paralleled the increased M(sum) and BMR. Dry mass of contour plumage increased in winter for both species and was associated with decreased thermal conductance in winter chickadees compared to summer chickadees. Chickadees and titmice show metabolic acclimatization similar to other temperate species.