The use of artificial breeding chambers as a conservation measure for cavity-nesting procellariiform seabirds: a case study of the Madeiran storm petrel (Oceanodroma castro)

Procellariiform seabirds are amongst the most severely threatened taxa worldwide. Whilst the specific threats vary among species, problems such as introduced predators, loss of suitable nesting habitat and inter- and intra-specific competition for nest sites are common to many situations. This paper reports on an experiment to increase the availability of secure nest sites at a colony of Madeiran storm petrels breeding on an islet (free from introduced predators) in the Azores islands where there is evidence of inter-specific competition. The provision of nest boxes that were designed to exclude larger species led to around a 12% increase in the size of the breeding population in the first year and a 28% increase over the original colony size in the second year. Over three seasons, the breeding success of storm petrels nesting in boxes averaged 2.9 times greater than that of birds at natural sites, despite their likely reproductive inexperience. The techniques presented here should serve as a model for conservation management of other burrowing procellariiform species in situations where colony size or breeding performance is believed to be constrained by nest site quality.     

Are nest boxes a viable alternative source of cavities for hollow-dependent animals? Long-term monitoring of nest box occupancy, pest use and attrition

Nest box programs have often been established to conserve hollow-dependent fauna but their effectiveness is unknown in many jurisdictions. We examined nest box effectiveness in a 10-year experimental study in the Mountain Ash (Eucalyptus regnans) forests of Victoria (south-eastern Australia) where the paucity of hollow-bearing trees is a significant conservation issue. We quantified occupancy by arboreal marsupials, infestation by pest invertebrates, and nest box attrition. We found a large proportion of nest boxes (68.8%) were never used, including by the endangered target species, Leadbeater’s Possum (Gymnobelideus leadbeateri). Nest boxes were more often occupied in younger forests (58.3% cf 4.1% for old forest) but these sites were also where infestations by the introduced European Honeybee (Apis mellifera) were greatest and where the probability of nest boxes collapsing was highest. Our data suggest that it is important to carefully target the locations where nest boxes should be established, but these same places are also those where most effort is required to maintain them, either by removing pest invertebrates and/or by re-attaching them to trees after they have fallen down.We recorded reasonable levels of occupancy by arboreal marsupials in young forest ∼2-3 years after box establishment, but then high levels of nest box attrition (>51%) occurred after 8-10 years. This suggests an “effective occupancy time” for arboreal marsupials of only ∼5 years.A key consideration must be to weigh the ecological and economic effectiveness of nest boxes against other strategies such as implementing alternative silvicultural systems that result in the creation and retention of more hollow-bearing trees within logged areas.     

笼内产蛋窝布置方式对蛋种鸡行为生理及死淘率的影响

现行蛋种鸡本交笼虽具备较大活动空间并能满足鸡只自然交配行为,但其饲养环境依然相对贫瘠,缺乏环境富集装置,存在啄羽啄肛等行为问题。该文探究了蛋种鸡本交笼中3种不同类型产蛋窝的使用效果及其对啄羽啄肛行为及生理应激反应的影响。结果表明,3种产蛋窝Nest1(长?宽?高)(90 cm?40 cm?60 cm)、Nest2(45 cm?40 cm?60 cm)、Nest3(70cm?52cm?60cm)在32周龄时窝内蛋比例分别为80.5%?7.8%、67.4%?8.1%、87.3%?7.6%,Nest1与Nest3窝内蛋比例、探窝次数及趴卧次数显著高于Nest2(P0.05),Nest1、Nest2、Nest3产蛋鸡只探窝时间无显著差异,设置产蛋窝后鸡只发出的攻击性啄、严重啄羽、轻度啄羽频次显著低于对照组(P0.05)。3种产蛋窝血浆皮质酮浓度无显著差异,但显著低于对照组(P0.05),对照组及Nest2总死淘率显著高于Nest1与Nest3(P0.05),对照组因啄死淘率显著高于Nest1、Nest2、Nest3(P0.05)。产蛋窝的设置可以满足鸡的行为需求,降低啄羽啄肛行为的发生、生理应激及因啄死淘发生风险。     

Can an introduced predator trigger an evolutionary trap in a colonial seabird?

Animals use environmental cues, social information and behavioural decision-making rules moulded by natural selection to decide where to breed. We assessed whether the presence of an alien nest predator, the Black Rat (Rattus rattus) is used by a colonial seabird, the Cory’s shearwater (Calonectris diomedea), as an environmental cue in the selection of breeding sites. We compared potential habitat preference using quality of breeders and nest fidelity as response to nest predation between two sub-colonies with different habitat characteristics, breeding success and predation pressure. Quality of individuals was better in the predated habitat and birds did not perceive the presence of predators signalling differences in predation risk and in turn of breeding success. This failure of perception could be at two levels: in the selection of habitat for first breeding and in the breeding dispersal following a reproductive failure. Preference for the sub-colony with higher predation risk suggests the presence of an evolutionary trap. In fact, the introduction of alien predators probably transformed the behaviour of shearwaters in a maladaptive response due to a mismatch between the new environmental factors and their behavioural and evolutionary algorithms. This can be a common pattern in other species with little behavioural plasticity, evolved in stable environments free of predators.     

Is the Yelkouan shearwater Puffinus yelkouan threatened by low adult survival probabilities?

Many seabird species are experiencing population declines, with key factors being high adult mortality caused by fishery by-catch and predation by introduced predators on nesting islands. In the Mediterranean, both of these pressures are intensive and widespread. We studied the adult survival of an endemic Mediterranean seabird, the Yelkouan shearwater (Puffinus yelkouan), between 1969–1994 and 2007–2010 in Malta and between 2004–2010 in France using mark–recapture methods. Mean annual survival probabilities for breeding adults were below 0.9 for all colonies and periods. Between 1969–1994, annual survival for adults of unknown breeding status was on average 0.74 (95% confidence interval: 0.69–0.80) in Malta, possibly as a result of various human disturbances (including illegal shooting), light pollution and fisheries by-catch. Over the period 2004–2010, we found strong support for variation in adult survival probabilities between breeders and non-breeders, and islands with and without introduced predators in France. Survival probabilities for non-breeders (0.95, 0.81–1.0) appeared to be higher than for breeders (0.82, 0.70–0.94), but were imprecise partly due to low recapture probabilities. In Malta, we found evidence for heterogeneity in survival probabilities between two unknown groups (probably breeders and non-breeders), and seasonal variation in survival probability. Birds were more likely to survive the period including the peak breeding season than an equally long period during which they roam widely at sea. Although annual adult survival probability was still low (0.85, 0.58–1.0), colony protection measures appear to have reduced mortality at nesting cliffs. A population model indicated that colonies in France and Malta would currently require continuous immigration of 5–12 pairs per year to maintain stable populations. Our estimates of adult survival probabilities over the past four decades are consistent with overall population declines. Threats to Yelkouan shearwaters require immediate management actions to avoid ongoing population declines in the western Mediterranean.     

Nest site restoration increases the breeding density of blue-tailed bee-eaters

For birds that excavate their own nest burrows, the availability of suitable nest sites and substrates may influence the number and density of breeding birds. However, few studies of burrow-nesting birds have experimentally manipulated nest site or substrate availability. The blue-tailed bee-eater (Merops philippinus) is a colony breeding, summer migrant that excavates nest burrows in sandy banks on Kinmen Island, 5 km east of mainland China. To test whether substrate availability influenced the density or reproductive success of breeding pairs of bee-eaters, we removed all vegetation and old nest holes on treated slopes and left control slopes unmanipulated in 2003 and 2004. Plant cover on control slopes was 37.7% (11.9-67.7%). Slope gradient, soil penetration resistance and vegetation height in front of slopes did not differ between treated and control slopes in either year. Combining data from both years, the density of active nests was significantly higher (3.1-fold) on treated slopes than on control slopes. However, the reproductive performance of bee-eaters nesting on treated and control slopes did not differ in either year. Thus, removing vegetation and old nest holes from slopes with sandy loam soil improved the breeding habitat and increased the number of breeding blue-tailed bee-eaters. This technique could be used to support and manage populations of this species and other burrow-nestling species with similar habitat requirements.     

Density and success of bird nests relative to grazing on western Montana grasslands

Grassland birds are declining at a faster rate than any other group of North American bird species. Livestock grazing is the primary economic use of grasslands in the western United States, but the effects of this use on distribution and productivity of grassland birds are unclear. We examined nest density and success of ground-nesting birds on grazed and ungrazed grasslands in western Montana. In comparison to grazed plots, ungrazed plots had reduced forb cover, increased litter cover, increased litter depth, and increased visual obstruction readings (VOR) of vegetation. Nest density among 10 of 11 common bird species was most strongly correlated with VOR of plots, and greatest nest density for each species occured where mean VOR of the plot was similar to mean VOR at nests. Additionally, all bird species were relatively consistent in their choice of VOR at nests despite substantial differences in VOR among plots. We suggest that birds selected plots based in part on availability of suitable nest sites and that variation in nest density relative to grazing reflected the effect of grazing on availability of nest sites. Nest success was similar between grazed plots and ungrazed plots for two species but was lower for nests on grazed plots than on ungrazed plots for two other species because of increased rates of predation, trampling, or parasitism by brown-headed cowbirds (Molothrus ater). Other species nested almost exclusively on ungrazed plots (six species) or grazed plots (one species), precluding evaluation of the effects of grazing on nest success. We demonstrate that each species in a diverse suite of ground-nesting birds preferentially used certain habitats for nesting and that grazing altered availability of preferred nesting habitats through changes in vegetation structure and plant species composition. We also show that grazing directly or indirectly predisposed some bird species to increased nesting mortality. Management alternatives that avoid intensive grazing during the breeding season would be expected to benefit many grassland bird species.     

Supply of tree-holes limits nest density of cavity-nesting birds in primary and logged subtropical Atlantic forest

Tree cavities are proposed to limit populations and structure communities of cavity-nesting birds. Although the greatest diversity of cavity-nesting birds is found in tropical and subtropical moist forests, little is known about how tropical logging affects the abundance of cavities or cavity-nesting birds. We compared the abundance of cavities and cavity nests between primary and selectively-logged subtropical moist Atlantic forest in Argentina, and conducted the first before-after controlled nest-box addition experiment to determine whether nest sites limit the breeding density of cavity-nesting birds in tropical or subtropical moist forest. Visual inspection of 86 cavities identified through ground-surveys revealed that only 19% were suitable for nesting birds, suggesting that cavity abundance may be overestimated in the literature on tropical forests. Suitable cavities were found in fewer than 1% of 1156 trees <60 cm dbh but 20% of 20 trees >100 cm dbh. Logged forest had half the basal area of primary forest, one third the density of large trees, nine times fewer cavities suitable for nesting birds, and 17 times fewer active nests. When we added nest boxes, nesting density increased on treatment plots but not on control plots in both logged and primary forest, suggesting that cavity supply can limit nest density even in relatively undisturbed forest. This is the first experiment to show how reduced cavity supply in logged tropical forest can limit breeding density of cavity-nesting birds. International initiatives such as forest certification should promote tropical timber management strategies that conserve large live cavity-bearing trees.     

Multi-Site Integrated Population Modelling

We examine the performance of a method of integrated population modelling for the joint analysis of different types of demographic data on individuals that exist in, and move between, different sites. The value of the approach is demonstrated by a simulation study which shows substantial improvement in parameter estimation when site-specific census data are combined with demographic data. The multivariate normal approximation to a multi-state mark-recapture likelihood is evaluated, and the performance of a diagonal variance-covariance matrix for the approximation is also examined. The work is motivated by a study of great cormorants. Analysis of the cormorant data suggests that breeders survive better than non-breeders, and also that probabilities of recruitment to breeding have been declining over time for all the colonies of the study. Supplementary material, including notes on the computation of standard errors and extended simulation results, are available online.     

Status and conservation of the seychelles black parrot

A study of the Seychelles black parrot Coracopsis nigra barklyi, restricted to Praslin Island in the central Seychelles, was carried out between July and September 1976. A synchronised watch on 23 August provided an estimate for the total population of 90 birds ± 20,65% of which were in the Vallée de Mai region. Regular movements out of the Vallée between 0800 h and 0900 h and returning between 1700 h and 1800 h were noted, and these were associated with foraging. Most important food items during the study were Verschaffeltia splendida, an endemic palm, and the introduced Averrhoabilimbi. Breeding is probably concentrated in the period October to February, and it is thought that the lack of many suitable nest sites (standing rotting trees of Pandanus, Lodoicea, and Albizia) may be the major factor regulating numbers. The provision of suitable nest boxes, a policy of leaving dead Albizia and Acacia trees standing as nest sites, and the planting of fruit trees such as Verschaffeltia, Averrhoa and Ficus are suggested to help the conservation of the species.     

Use of time-activity budgets to measure early progress of a social attraction restoration project

Social attraction is a useful technique for re-establishing or relocating waterbird colonies and other species groups. However, little information exists regarding how newly attending individuals behave when the social environment is influenced predominantly by artificial stimuli. To help assess early progress of colony re-establishment, we compared time-activity budgets of common murres (Uria aalge) at a social attraction site (Devil’s Slide Rock; DSR) in central California with two nearby reference colonies during the first 3 years (1996–1998) of efforts. Murres at all colonies spent over 95% of their time engaged in resting, comfort, courtship, and alert activities during the pre-breeding period and over 88% of their time in similar activities during the breeding period. Although patterns were similar overall, comparisons of pooled and year-specific time budget data revealed significant differences between all three colonies, especially during pre-breeding. Murres at DSR typically engaged in comfort behaviors less frequently and in alert and courtship behaviors more frequently than reference colonies. Differences likely were due to recent re-establishment, including lower bird densities and higher proportions of non-breeders and first-time breeders at DSR, along with other factors such as disturbance. Results indicate that newly attracted birds at DSR behaved “normally” even though the social environment was influenced predominantly by artificial stimuli. Furthermore, re-established breeding in the first year of efforts, subsequent colony growth, and high productivity reflected successful restoration efforts. Thus, time-activity budgets can provide important measures of early progress of social attraction efforts and as such can be used to inform adaptive management decisions.     

Influence of food availability, predator density and forest fragmentation on nest survival of New Zealand robins

The decline of avian populations in fragmented landscapes is often attributed to a decrease in nest survival rates for species breeding within these habitats. We tested whether fragment size and connectivity, livestock grazing, predator density or invertebrate biomass were correlated with nest survival rates for an endemic New Zealand species, the North Island robin (Petroica longipes). Across three breeding seasons (2002-2005) daily nest survival rate for the 203 robin nests monitored in 15 forest fragments was 0.315 (SE 0.003), with nest survival rates increasing with invertebrate biomass (indexed with pitfall traps) and marginally decreasing with fragment size. Footprint tracking rates for exotic ship rats (Rattus rattus), which are likely to be the key nest predator, varied greatly among fragments, but were not a useful predictor of nest survival. We found no relationship between the number of fledglings per successful nesting attempt and invertebrate biomass. We conclude that fragment size and connectivity does not appear to be negatively influencing robin nest survival, potentially because of the already high impact that mammalian nest predators have in this unique system.     

Are urban parks refuges for bumble bees Bombus spp. (Hymenoptera: Apidae)?

Declines in bee populations have been documented in several parts of the world. Bees are dependent upon flowering plants for resources, and flowering plants often depend upon bees for pollination services. Bees can therefore serve as indicator species of habitat degradation due to these relationships with flowering plants. This study investigates how the bumble bee community in San Francisco has responded to urbanization and which urban park characteristics are important for the current community’s structure. To answer these questions we sampled bumble bees, in 18 urban parks and two nearby wild parks. We estimated park characteristics and used multiple regression analysis to determine which characteristics predicted bumble bee abundance and species richness. Bumble bee abundance was positively associated with resource availability or proxies of resource availability; “natural area” (areas that contain remnant fragments that have been largely unchanged by human activity) in 2003 and nest site abundance and openness of the surrounding matrix in both 2003 and 2004. Bumble bee species richness was negatively associated with abundance of a dominant species, Bombus vosnesenskii, in 2004. The importance of the surrounding matrix suggests that these parks do not act as islands. Accordingly, area of park did not explain species richness, while abundance of the dominant competitor did. The species that was most influenced by competition, Bombus sitkensis, uses rodent holes as nest sites and is possibly excluded from nest sites by the early emerging B. vosnesenskii, another subterranean nester. The species least influenced by competition, Bombus melanopygus, is able to use both rodent holes and abandoned bird nests as nest sites.     

Establishment of a new breeding colony of Gould’s petrel (Pterodroma leucoptera leucoptera) through the creation of artificial nesting habitat and the translocation of nestlings

Gould’s petrel (Pterodroma leucoptera leucoptera) was restricted, essentially, to a single breeding locality - Cabbage Tree Island, Australia. As a safeguard against extinction, an additional breeding colony was established on nearby Boondelbah Island, where artificial nesting habitat was created by installing 100 plastic nest boxes. Over two years, a total of 200 nestling Gould’s petrels were translocated from Cabbage Tree Island to these boxes. Colonies on both islands were then monitored for a further four years. Selection of nestlings for transfer was based on prior knowledge of growth, plumage development and emergence from the burrow, and aimed to select only birds that were 11-28 days from fledging (DBF) in 1999 and 11-22 DBF in 2000. Of the first 100 nestlings translocated to Boondelbah Island (in March 1999), 95 fledged successfully 8-27 days after transfer (mean = 17.3 days). Of the second 100 nestlings translocated (in March 2000) all successfully fledged 9-22 days after transfer (mean = 15.1 days). The removal of young had no discernible effect on the subsequent breeding productivity of the donor pairs. In all, 41 Gould’s petrels have been recorded at the new colony on Boondelbah Island, where at least 27 nest boxes have been visited. Ten translocated fledglings (nine male, one female) have returned to the translocation site, taking up nest boxes that were, on average, 5.5 m from the box from which they fledged. An additional 27 non-translocated birds, of unknown origin, have also nested in nest boxes on Boondelbah, along with four birds previously known from Cabbage Tree Island. Two nestlings transferred to Boondelbah Island have returned to Cabbage Tree Island. Within five years of the first translocation, the newly established colony on Boondelbah Island has produced a total of 24 eggs and 14 fledglings. The translocation technique developed for Gould’s petrel has broad applicability, being readily adaptable for other burrow-nesting seabirds.     

Influence of temperature in roost selection by Pipistrellus pygmaeus (Chiroptera): relevance for the design of bat boxes

The soprano pipistrelle (Pipistrellus pygmaeus) is a house-dwelling bat, whose maternity colonies are often affected by exclusion from buildings in southern Europe. Bat boxes with a suitable thermal behaviour can provide alternative roosts. However, this is particularly difficult to achieve in hot climates, where boxes may overheat. We studied roost temperatures and roost thermal preferences of this bat in attics and roofs in a Mediterranean region. Roosts reached high temperatures, experienced great thermal fluctuations and had wide spatial thermal ranges. Bats preferred the warmest locations within roosts, indicating that they are a heat tolerant species. However, they avoided temperatures of 40 °C and above, suggesting that this is the upper limit of the species thermally neutral zone. The study of experimental sets of white, grey and black boxes demonstrated that the latter were the ones that most often reached the temperatures observed in roosts in buildings. They were also the ones occupied by larger numbers of bats. These results suggest that, even in hot Mediterranean climates, black boxes are the best option as alternative roosts for evicted colonies. However, on particularly hot days, bats left them, suggesting that black boxes could be improved by creating a wider thermal range.     

Resolving the urban nest predator paradox: The role of alternative foods for nest predators

Urbanization is a leading cause of species endangerment in the United States; however, certain species thrive in urban habitats. The loss of key predators or the addition of new predators in urban areas could alter the structure of urban communities. A reduction in nest predation is hypothesized to explain the high density of urban birds, yet urban areas typically have increased populations of avian nest predators. The loss of important nest predators in urban habitats, prey switching of urban predators, or successful nest defense against avian nest predators could explain this urban nest predator paradox. To assess these hypotheses I compared nest predation rates of Northern mockingbirds (Mimus polyglottos) in parking lots and residential neighborhoods to populations in pastures and wildlife preserves during 2007–2009 in Florida, USA and placed video cameras on a subset of nests in 2008–2009. Data do not support the hypothesis that urban nest predation rates are consistently lower than non-urban nest predation rates. Of the 56 nest predation events recorded, cats were the dominant urban predator and Cooper’s hawks (Accipiter cooperii) were the dominant non-urban predator. There was no evidence for a loss of important nest predators in urban habitats; however, prey switching by Cooper’s hawks likely occurred. There was also indirect evidence for the importance of nest defense. Furthermore, some of the cats recorded as nest predators in residential neighborhoods were owned cats and all but one cat predation event occurred at night. To reduce nest predation rates, cat owners should keep their cats indoors at night.     

A national scale inventory of resource provision for biodiversity within domestic gardens

The human population is increasingly disconnected from nature due to urbanisation. To counteract this phenomenon, the UK government has been actively promoting wildlife gardening. However, the extent to which such activities are conducted and the level of resource provision for biodiversity (e.g., food and nesting sites) within domestic gardens remains poorly documented. Here we generate estimates for a selection of key resources provided within gardens at a national scale, using 12 survey datasets gathered across the UK. We estimate that 22.7 million households (87% of homes) have access to a garden. Average garden size is 190 m², extrapolating to a total area of 432,924 ha. Although substantial, this coverage is still an order of magnitude less than that of statutory protected areas. Approximately 12.6 million (48%) households provide supplementary food for birds, 7.4 million of which specifically use bird feeders. Similarly, there are a minimum of 4.7 million nest boxes within gardens. These figures equate to one bird feeder for every nine potentially feeder-using birds in the UK, and at least one nest box for every six breeding pairs of cavity nesting birds. Gardens also contain 2.5-3.5 million ponds and 28.7 million trees, which is just under a quarter of all trees occurring outside woodlands. Ongoing urbanisation, characterised by increased housing densities, is inevitable throughout the UK and elsewhere. The important contribution domestic gardens make to the green space infrastructure in residential areas must be acknowledged, as their reduction will impact biodiversity conservation, ecosystem services, and the well-being of the human population.     

Do Ural owls (Strix uralensis) suffer from the lack of nest sites in managed forests?

Nest site availability, preferences and quality for Ural owls (Strix uralensis) were studied in managed forests and a large nature reserve in Estonia. The owl's density was relatively higher in the reserve. Ural owls bred in tree cavities and stick nests, but preferred the cavities. Suitable cavities were very rare compared to stick nests, and most cavities were found in the reserve. Pairs having no suitable cavities in their territories started to breed less frequently, but no difference was detected in young produced per breeding attempt between cavity nests and stick nests. Used cavities and stick nests as well as unused stick nests were situated in similar stands and landscapes, but nest tree and nest characteristics of cavity nests were distinct. The study shows that in managed forests the lack of large snags and tree cavities may limit the numbers of Ural owls, which accept these structures for breeding more readily than stick nests. Retention of large cavity-forming trees in forestry operations may be an effective conservation strategy for this species.     

Hunting habitat selection by hen harriers on moorland: Implications for conservation management

We examine habitat use by hunting hen harriers Circus cyaneus at three study sites in Scotland to evaluate whether foraging patterns differ between sexes, sites, and stages of the breeding period. We modelled time spent hunting in focal plots as a function of habitat and nest proximity. Male hunting intensity (time spent hunting per hour of observation and km²) varied between sites and breeding periods, being lower during the nestling than the incubation period. Habitat use patterns were mostly consistent among study sites, which is important for developing species management recommendations applicable over the species’ range. Males avoided improved grassland, and selected areas of mixed heather and rough grass (with an optimum at ca. 50% heather cover). The effect of nest proximity was small. In contrast, females hunted mainly within 300-500 m of the nest, with a small additive effect of vegetation cover, areas of fragmented heather being preferred. Habitat management to benefit foraging harriers will involve creating (or maintaining) mosaics of heather/grassland around nest areas. Additionally, it might be possible to manipulate habitat to reduce conflict in areas where harrier predation on red grouse is important by segregating areas holding highest grouse densities (with high heather cover) from those favoured for harrier foraging (heather-grass mosaics). However, it would be necessary to test whether these manipulations might also influence harrier nest distribution, an effect which could negate any benefits from this strategy.     

Nesting habitat of the glossy black-cockatoo in central New South Wales

The reliance of cockatoos upon large hollows for nesting makes them vulnerable to any reduction in this resource. Species inhabiting forests managed for timber production are at risk because logging has the capacity to reduce hollow abundance significantly. In this study I identified the factors significantly associated with the selection of nest trees and nest sites by glossy black-cockatoos. Glossy black-cockatoos nested in vertical spouts in large trees. Nests were more likely to be located relatively high in senescent trees or standing dead trees (snags), factors most likely related to hollow suitability. As the density of potential nest hollows increased within a site, so to did the relative probability of it being used for nesting. The number of potential hollows serves as an index for the availability of suitable hollows. The persistence of glossy black-cockatoos within the study area will require careful management of nesting resources. Maximising the available hollow resource within known nesting areas is desirable. This is most efficiently achieved by facilitating the recruitment of large trees. This will require the exclusion of logging from nesting areas. Snags are a critical nesting resource. Information on snag dynamics is required and active intervention, such as the erection of nest boxes, may be necessary if unsustainable snag loss is occurring.