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Roosting Preferences of North Island Brown Kiwis ( Apteryx mantelli )
Abstract
The North Island Brown Kiwi (Apteryx mantelli) is a nocturnal endangered species endemic to New Zealand. The protection of suitable habitat is key to the species' recovery; however, little is known about their habitat requirements. We studied the diurnal roosting behaviours of kiwis by intensely tracking 41 radio-tagged, non-breeding adults from May 2010 to February 2012 on Ponui Island, New Zealand. From these birds, we collected 3,997 roosting locations in three different macro-habitat types (scrub, forest, and swamp) and described 223 roosting burrows in the forest macro-habitat. Overall, we discovered that kiwis were roosting generalists; three quarters of the study population was found in more than one macro-habitat and just 5% used only a single type of micro-habitat. However, using compositional analyses, we found that they did show some clear preferences. On a macro-habitat level, kiwis preferred forest habitat over scrub or swamp. Furthermore, on a micro-habitat level, they preferred roosting inside trees, either living or dead, and holes in the ground over roosting in decomposing vegetation or holes associated with creeks. The least preferred micro-habitat type consisted of overhangs produced by ground slips. Kiwis were most likely to use long burrows with small entrances that were oriented downhill. Our findings suggest that priority should be given to protecting mixed landscapes with large, mature, dynamic native forests.
... Kiwi are predominantly found in New Zealand native forest habitats and forage during the night consuming primarily invertebrates, earthworms, beetle larvae and small amounts of fruit and leaves [3,4]. During day-light hours they retreat to burrows, preferably in either living or dead trees, or holes in the ground in native forest habitats [5]. ...
... The literature [13,14] suggests that day-time roost or day/night-time ranges may be influenced by habitat area and bird density. Restricted range may potentially have been an issue in this study in relation to the proximity of the Kaipara Harbour water boundary (Figures 2 and 3), however, Jamieson et al [5] reported that free-roaming birds used swamp areas to a limited extent. It is suggested that the property perimeter fence had little if any impact on roost range, as there was substantial distance between the edge of the ranges and the property boundary. ...
... As the population density at the Mataia site was low, less overlap in roost ranges within years was expected. However, an overlap of roost ranges has been demonstrated by Jamieson et al. [5] and may reflect the proximity of suitable habitat at the Matai site. The overlapping roost areas for Taranaki (female) and Charlie (male) was expected as these birds had pair bonded. ...
Information on the day-time roost areas of North Island brown kiwi (NIBK) (Apteryx mantelli), particularly post-translocation, is limited. This study aimed to determine the day-time roost areas of newly translocated NIBK and compare these with birds that had established from a translocation in the previous year. Radio telemetry was used to monitor sub-adult NIBK in the first three weeks post-translocation simultaneously with birds released in the previous year. The data from 15 birds (nine translocated in 2014 and six translocated in 2013) were used to calculate the area over which roost sites were distributed. Areas were estimated using Minimum Convex Polygon (MCP, Ha) and 50 percentile kernel density estimation (KDE, Ha). No significant difference in MCP was determined between newly translocated 2014 birds (21.3 Ha, SE 7.92) and those translocated in 2013 (22.85 Ha, SE 10.84) or between KDE50 for 2013 birds (16.30 Ha, SE 7.44) compared with 2014 birds (20.66 Ha, SE 8.29). Within the first three weeks post-translocation, most of the 2014 birds remained within the vicinity of their release site, which may be due to a combination of suitable habitat/roost sites and the ‘anchoring’ effect of previously established 2013 birds. This study provides new information on roost areas of newly translocated NIBK and highlights the importance of post-translocation monitoring.
... Second, bird extractability and sampling accessibility could differ between roosting and foraging birds and between different age groups and sexes while roosting. For instance, during the day adult kiwi are more likely to be located in deep burrows while juveniles are more commonly found on the surface potentially making the latter more extractable; at night females have been reported more frequently in open pasture compared to males potentially making them more accessible for sampling (Wilson 2014;Dixon 2015;Jamieson et al. 2016). Third, previous work has raised concerns about the potential for female-biased samples from night-time encounter catching resulting from differences in behaviour (e.g. ...
... Territoriality varies notably between NI brown kiwi populations, from low or even absent in areas where birds roam overlapping home ranges, to areas where birds aggressively defend territory borders (McLennan & Potter, 1992;Potter, 1990;Taborsky & Taborsky, 1999;Ziesemann, 2011). This variation could be linked to variable territory quality, which is supported by the fact that foraging success varies with habitat type (Cunningham & Castro, 2011;Dixon, 2015); habitat utilization does not reflect habitat availability (Dixon, 2015;Jamieson et al., 2016); territory size varies with the proportion of preferable habitat (Taborsky & Taborsky, 1995); nests are nonrandomly placed in relation to habitat type (Taborsky & Taborsky, 1995); and hatching success tends to be higher in tree logs compared to other, less spatially restricted, nest types (I. Castro, unpublished data;Wilson, 2014;Ziesemann, 2011). ...
The breeding system and mating strategy of a species are at the heart of its behavioral ecology and part of determining its population dynamics. Thus, understanding breeding and mating behavior, and its flexibility, is important for accurate population modeling and successful conservation management. Here, we combine previous work with species‐specific data and phylogenetic context to shine the spotlight on the breeding system of North Island (NI) brown kiwi, Apteryx mantelli , in a conservation context. The NI brown kiwi is of wide interest as a ratite, which are known for their variable breeding biology both within and between species, and its dire need of conservation management. With the aid of data from a long‐term study in a rare, high‐density population, we conclude that, although NI brown kiwi have several features characteristic of monogamous bird species (substantial investment in offspring by both parents, long‐life expectancy, and well‐developed sense of olfaction), it has as many that are consistent with potential for polygamy (uneven quality and distribution of resources, long and asynchronous breeding season, super‐precocial chicks, and non‐monogamous relatives). Consequently, we suggest that (1) the breeding system of NI brown kiwi is more flexible than has been widely recognized, and (2) further study of NI brown kiwi mating behavior would greatly benefit its conservation planning. Specifically, the prevalence of polygamy will directly affect genetic admixture, maintaining of genetic diversity, and distribution of parentage—all crucial factors influencing translocation success and genetic rescue. We argue that the NI brown kiwi study system could contribute to the increased incorporation of behavioral aspects in conservation management, and we provide suggestions for informative studies that would facilitate this.
... The kiwi is a nocturnal animal and can range widely in search of food as well as use a multitude of burrows within its range [34,35]. Despite the original example of this species of tick being found on a duck, the kiwi tick is almost exclusively host specific and aberrant hosts are very rare 18], suggesting that it would be an advantage for the tick to be sedentary and to be capable of sustained quiescence in the event of the spasmodic presence of hosts. ...
Background
Numerous laboratory and fewer field-based studies have found that ixodid ticks develop more quickly and survive better at temperatures between 18 °C and 26 °C and relative humidity (RH) between 75 and 94%. Ixodes anatis Chilton, 1904, is an endophilic, nidicolous species endemic to North Island brown kiwi ( Apteryx mantelli ) (NIBK) and the tokoeka ( Apteryx australis ), and little is known about the environmental conditions required for its development. The aims of this study were to determine and compare the conditions of temperature and RH that ensure the best survival of the kiwi tick and the shortest interstadial periods, in laboratory conditions and outdoors inside artificial kiwi burrows.
Methods
Free-walking engorged ticks were collected off wild kiwi hosts and placed in the laboratory under various fixed temperature and humidity regimes. In addition, sets of the collected ticks at different developmental stages were placed in artificial kiwi burrows. In both settings, we recorded the times taken for the ticks to moult to the next stage.
Results
Larvae and nymphs both showed optimum development at between 10 °C and 20 °C, which is lower than the optimum temperature for development in many other species of ixodid ticks. However, larvae moulted quicker and survived better when saturation deficits were < 1–2 mmHg (RH > 94%); in comparison, the optimum saturation deficits for nymph development were 1–10 mmHg.
Conclusions
Our results suggest that the kiwi tick has adapted to the stable, but relatively cool and humid conditions in kiwi burrows, reflecting the evolutionary consequences of its association with the kiwi.
... The kiwi is a nocturnal animal and can range widely in search of food as well as use a multitude of burrows within its range (34,35). Despite the original example of this species of tick being found on a duck, the kiwi tick is almost exclusively host-speci c (aberrant hosts are very rare; 18) and this suggests it would be an advantage for the tick to be sedentary and to be capable of sustained quiescence in the event of the spasmodic presence of hosts. ...
Background
Numerous laboratory and fewer field-based studies have found that ixodid ticks develop more quickly and survive better at temperatures between 18 and 26°C and relative humidity between 75% and 94%. Ixodes anatis Chilton, 1904, is an endophilic, nidicolous species endemic to North Island brown kiwi ( Apteryx mantelli, NIBK ) and the tokoeka ( Apteryx australis ) and little is known about the environmental conditions required for its development. Our aims in this study were to determine and compare the conditions of temperature and RH that ensured the best survival, and the shortest interstadial periods for the kiwi tick, in the laboratory and outdoors inside artificial kiwi burrows.Methods
We collected free walking engorged ticks off wild kiwi hosts and placed them in the laboratory at various fixed temperature and humidity regimes. We also placed sets of different stages of these ticks in artificial kiwi burrows and in both cases, recorded the times taken for the ticks to moult to the next stage.ResultsWe found that larvae and nymphs both showed optimum development between 10-20°C, which is lower than many other species of ixodid ticks. However, larvae moulted quicker and survived better when saturation deficits were <1-2 mmHg (RH>94%) while for nymphs the optimum saturation deficits were 1-10 mmHg.Conclusions
We believe that the kiwi tick has adapted to stable, but relatively cool and humid conditions in the burrows reflecting the evolutionary consequences of its association with the kiwi.
... The kiwi is a nocturnal animal and can range widely in search of food as well as use a multitude of burrows within its range (Dixon, 2015, Jamieson et al., 2016. The tick too is exclusively host-speci c (aberrant hosts are very rare; see Heath 2010) and this suggests it would be an advantage for the tick to be sedentary and to be capable of sustained quiescence in the event of the spasmodic presence of hosts. ...
Background Numerous laboratory and few field-based studies have explored the influence of microclimates on developmental times of different stages of various species of ixodid ticks and found that most of these species develop quicker and survive better at temperatures between 18 and 26°C and relative humidity between 75% and 94%. Ixodes anatis Chilton, 1904, or kiwi tick, is an endophilic, nidicolous species endemic to North Island brown kiwi (Apteryx mantelli, NIBK) and the tokoeka (Apteryx australis). Little is known about the environmental conditions that are ideal for the development of the kiwi tick. Our aims in this study were to determine and compare the conditions of temperature and RH that ensured the best survival, and the shortest interstadial periods for the kiwi tick, in the laboratory and outdoors inside artificial kiwi burrows.
Methods We collected free walking engorged ticks off wild kiwi hosts and placed them in the laboratory at various fixed temperature and humidity regimes. We also placed sets of different stages of these ticks in artificial kiwi burrows and in both cases, recorded the times taken for the ticks to moult to the next stage.
Results We found that larvae and nymphs both showed optimum development between 10-20°C, which is lower than many other species of ixodid ticks. However, larvae moulted quicker and survived better when saturation deficits were <1-2 mmHg (RH>94%) while for nymphs the optimum saturation deficits were 1-10 mmHg.
Conclusions We believe that the kiwi tick has adapted to stable, but relatively cool and humid conditions in the burrows reflecting the evolutionary consequences of its association with the kiwi.
... The kiwi is a nocturnal animal and can range widely in search of food as well as use a multitude of burrows within its range [34,35]. Despite the original example of this species of tick being found on a duck, the kiwi tick is almost exclusively host specific and aberrant hosts are very rare 18], suggesting that it would be an advantage for the tick to be sedentary and to be capable of sustained quiescence in the event of the spasmodic presence of hosts. ...
All five species of kiwi (Apteryx spp.) are listed as threatened or near threatened, and an important aspect of kiwi conservation is understanding the biology of parasites because of their potential to act as disease vectors and hinder kiwi survival. Although the ectoparasite fauna on kiwis has been categorized, there is a paucity of information on the biology of the kiwi tick, Ixodes anatis, and other parasites found on this unusual avian host. Here we explore the presence of I. anatis in burrows known to be used by North Island brown kiwi, Apteryx mantelli. There was a significant positive correlation between the frequency with which burrows were used by kiwi and both tick intensity and prevalence. The potential consequences of extended use of burrows by kiwi for nesting and tick intensity are discussed. Monthly tick distributions for varying age/sex classes are described as well as age/sex class distribution in different burrow types, with other invertebrates found in burrows also noted. Given the conservation risk for kiwi and the endemic status of I. anatis, understanding the impact of this tick species on kiwi as well as its natural history should be a priority for future research.
Background
As parasites spend a large amount of their life cycles on their hosts, to gain a better understanding of how host-parasite systems work, information about the life cycle of the parasite is important. Numerous laboratory and few field-based studies have explored the influence of microclimates on developmental times of different stages of various species of ixodid ticks and found that most of these species develop quicker and survive better at temperatures between 18 and 26°C and relative humidity between 75% and 94%. Ixodes anatis Chilton, 1904, or kiwi tick, is an endophilic, nidicolous species endemic to North Island brown kiwi (Apteryx mantelli, NIBK) and the Tokoeka (Apteryx australis). Little is known about the environmental conditions that are ideal for the development of the kiwi tick. Our aims in this study were to determine and compare the conditions of temperature and RH that ensured the best survival, and the shortest interstadial periods for the kiwi tick, in the laboratory and outdoors inside artificial kiwi burrows.
Methods
We collected free walking engorged ticks off wild kiwi hosts and placed them in the laboratory at various fixed temperature and humidity regimes. We also placed sets of different stages of these ticks in artificial kiwi burrows and in both cases, recorded the times taken for the ticks to moult to the next stage.
Results
We found that temperature had a larger impact on the moults between stages than relative humidity, and larvae and nymphs both showed optimum development between 10-20°C, which is lower than many other species of Ixodid ticks. However, larvae moulted quicker and survived better when saturation deficits were <1-2 mmHg (RH>94%) while for nymphs the optimum saturation deficits were 1-10 mmHg.
Conclusions
We believe that the kiwi tick has adapted to stable, but relatively cool and humid conditions in the burrows reflecting the evolutionary consequences of its association with the kiwi.
The use of different habitats during foraging, roosting, social behavior, and nesting was studied in the North Island Brown Kiwi (Apleryx australis mantelli) with the use of radio telemetry. We chose a forest with a patchy distribution of native and introduced habitat types, the Waitangi Forest, to compare habitat availability with habitat use within the ranges of transmitter tagged individuals. During their nocturnal activity phase, Brown Kiwis preferred native forest and serai vegetation over man-made pine forest, marshes, and roads/pasture. During the daytime, kiwis roosted preferentially in marshes and successional vegetation. Social behavior, mostly calling, occurred in the same habitats as did all other nightly activity. Nest sites were preferentially located in or within 25 m of native or serai vegetation. These habitats are selectively used by chicks during foraging in their first weeks after hatching, when chicks are only able to walk short distances. Habitat types seem to be used selectively by kiwis because of their availability of food and shelter sites, regardless of whether they are natural or anthropogenic habitats. Additionally, the needs of young have to be considered when spacing patterns of adults are interpreted. Territories included a certain area of "preferred habitats" irrespective of total territory size. With sufficient access to these patches kiwis are able to survive even in poor habitats like pine forests. Only minor changes in forest management practices (e.g. allowing for wide road margins and preserving remnants of native forest and marshes) would suffice to greatly support the survival and propagation of kiwis. We discuss the importance of the selective use of small habitat patches as a precondition for the ability of kiwis to settle in a wide variety of environments, both natural and modified.
The upper Bay of Fundy is a critical stopover site for Semipalmated Sandpipers (Calidris pusilla) during their fall migration. However, little is known about factors that influence selection of feeding and roosting sites by these birds, or the extent to which birds move between different sites during their time in the region. Using radio-telemetry, we studied movement patterns, examined habitat use, and tested hypotheses associated with factors influencing foraging and roost-site selection. Movements of radio-tagged sandpipers were tracked in the upper Bay of Fundy in August 2004 and 2005. In 2004, sandpipers from the Minas Basin, Nova Scotia and Chignecto Bay, New Brunswick and Nova Scotia, were tracked, and in 2005, sandpipers were tracked only in Chignecto Bay. Sandpipers were highly mobile in both the Minas Basin 2004 and Chignecto Bay 2005, making daily movements of up to 20 km between foraging and roosting sites, although very little movement was detected in Chignecto Bay in 2004. Migrating sandpipers appeared to select foraging sites based on relative safety, as measured by distance to cover, provided that these sites offered an adequate food supply. Similarly, roosting sandpipers preferred sites that were far from nearby trees that might offer cover to predators. This preference for safe sites became more apparent later in their stay in the Bay of Fundy, when birds were heavier and, therefore, possibly more vulnerable to predation. Semipalmated Sandpipers appear to be flexible during their time in the upper Bay of Fundy, displaying year-to-year and site-to-site variability in movement and mudflat usage. Therefore, multiple, synchronized population counts should be conducted at known roost sites in order to more accurately estimate Semipalmated Sandpiper abundance in this region. Furthermore, in a highly dynamic system where food can be variable, landscape features such as distance to cover may be important factors to consider when selecting candidate sites for shorebird conservation measures.
Thermal factors potentially important in the selection of nocturnal roosts by birds include shelter from wind, local increases in air temperature, and improvement in radiation balance. The relative importance of these 3 factors was analyzed using data describing the thermal relations of Phainopepla nitens and the meteorological properties of its winter roost sites. Shelter from forced convection provides c5 times more thermal benefit than improvement of radiation balance. Possible metabolic heating by the bird of air within the roost site is unimportant.-from Author
The advantages and disadvantages of breeding in nestboxes are well known,
whilst the merits of roosting in nestboxes during the non-breeding season
remain poorly understood. Here I review the advantages and disadvantages of
using nestboxes as roosting sites during the non-breeding season. The main
advantage of nestboxes is that they increase the number of cavities available
for roosting and birds gain considerable thermal benefits and energy savings,
when compared to congeners roosting outside of cavities. However, the main
disadvantage is that roosting birds are widely targeted by detrimental ectoparasites,
and birds actively avoid nestboxes where ectoparasites are abundant.
Meanwhile, there is insufficient evidence to make any firm conclusions as to
whether roosting in nestboxes increases or decreases predation risk and this is
an area, which warrants further research. Consequently, there is a great deal of
variation in the quality of individual nestboxes as roosting sites, and interspecific
competition results in larger and more dominant species roosting in preferred
nestboxes. In summary, this review emphasises the importance of nestboxes to
roosting birds during the non-breeding season.
Eptesicus vulturnus, Chalinolobus morio, Nyctophilus geoffroyi, N. gouldi and Mormopterus planiceps all selected roosts with entrances and cavities having one dimension not much larger than themselves. None was far from water and, although there were significant differences between species values of some roost attributes, the similarities between them are probably more important. None of these species is highly selective. Colony size was variable, but tended to be small and segregated by sex and species. A design for an artificial roost is presented. -from Authors
Brown Kiwi (Apteryx mantelli) are in serious decline despite immense conservation efforts. The lack of fundamental information on Kiwi breeding is in part because of the low density of most populations and their nocturnal habits. We report on the nesting success and breeding ecology of an exceptionally high-density population of Brown Kiwi over 3 years. Nesting success was high (47%) compared with other Brown Kiwi populations and 85% of failures occurred during incubation. In contrast, fledging success was very high (89%). Most clutches had one egg (69%), and second and replacement clutches were rare. Significantly more chicks hatched in reused nests than previously unused burrows. In addition, two nest usurpations and one cooperative nest were observed. We suggest that competition for resources associated with high densities result in reduced clutch-size, nest reuse and nest usurpation and that such life-history traits are particularly relevant for species such as Brown Kiwi with high energetic demands for breeding. Given that the density of Kiwi on Ponui Island is indicative of pre-human New Zealand, this study provides insights into the breeding ecology of Brown Kiwi not otherwise possible. Indeed, our study reveals certain previously unknown aspects of Brown Kiwi life-history indicating ecological resilience.
Twelve kiwis were radio-tagged and tracked for 12-78 weeks in two sites in Hawke's Bay. Four bonded pairs had ranges of 19.1 to 42.3 ha (estimated by the convex polygon method), which were apparently defended against other kiwis. Two unmated females had ranges of 48.0 and 43.1 ha. Another unmated female occupied a narrow, circular strip, 5.4 km long, covering about 26 ha. The ranges of four kiwis in scrubland and eight in climax beech/podocarp forest were similar in size. Kiwis roosted on 36% of days in burrows which they excavated themselves. On other days they roosted in natural subterranean tunnels, or in hollows under fallen trees, thick vegetation, or inside logs. Generally they roosted in a different place each day but often returned to sites they had used previously. Members of bonded pairs roosted apart on 92% of days, in different parts of their range. In terms of current understanding of population genetics, reserves for kiwis in Hawke's Bay probably need to be at least 7500 ha in order to support a genetically enduring population of 250 breeding pairs. None of the existing reserves meet this requirement.
Kiwi have declined markedly in abundance and range since human settlement of New Zealand. Three of the four species are still extant in mainland forests, despite decades of co-existence with various introduced mammals. Little spotted kiwi is now probably confined to offshore islands. The role of introduced mammals in these population declines was evaluated by measuring the survival rates of adults, eggs and chicks of brown kiwi (A. mantelli) and great spotted kiwi (A. haastii) in mainland forests. Mortality rates of adults ranged from 5%-16% and did not differ significantly between species or sexes. Overall, 14 out of 209 adult kiwi died during 159.6 radio-tracking years. Predators definitely caused five of these deaths. Sixty-nine (68%) of 102 eggs from 77 nesting attempts by 48 pairs failed to hatch. Predators probably caused about 10% of egg failures. Only three of 49 chicks probably survived to adulthood, indicating a juvenile mortality rate of about 94%. Predators killed at least 8% of chicks, 45% of juveniles, and possibly as many as 60% of all young kiwi. Ferrets and dogs were the main predators of adult kiwi, possums and mustelids were the main egg predators, while stoats and cats were largely responsible for the deaths of young kiwi. Population models show that northern brown kiwi are currently declining at 5.8% per annum. This decline could be halted by cutting the current predation rates on young kiwi by about 34% to 33%.
There are a lot of studies about relationships between prey and predators. However most have focused on the influence of lethal predators on their prey. We suggested that non-lethal effects may also be very important for a complete understanding of prey-predator interactions. Among many influencing factors predation is important because it affects survival probability, especially in winter, which is a critical period for many passerines living in temperate zones. Apart from killing prey, predators may also have an indirect influence on the choice of nocturnal resting sites. Therefore, small passerines should detect and avoid places where a predator has operated previously. We tested this prediction using data on wintering small passerines, mainly on Great Tits. The study was performed during the winter season of 2005/2006 in western Poland. In the experiment, we put fur and mangled feathers in half of 100 randomly selected nest boxes. Boxes were checked every ten days, from January-March. The birds showed a significantly stronger preference towards "clean" nest boxes (without predator traces). It seems that non-lethal predator influence modifies winter dispersion of birds and wintering passerines may detect, by visual signals left behind, nest boxes where predation has previously occurred.
We studied habitat selection by radio tracking Natterer's bats Myotis nattereri foraging in a grassland–woodland landscape. We tested the hypothesis that selection of foraging habitat is random at two levels: firstly, the selection of individual foraging ranges and secondly, the choice of foraging habitats made by individuals within these foraging ranges. Habitat selection was random at neither level. When selecting foraging ranges, bats maximized the area of semi-natural broad-leaved woodland and improved grassland and minimized that of dense coniferous plantations. During foraging, semi-natural broad-leaved woodland and river corridors were preferred, while dense coniferous plantations were avoided. Within individual foraging ranges, the intensity of foraging activity over river corridor habitat and semi-natural broad-leaved woodland was 8.2 and 3.8 times higher, respectively, than that over improved grassland. For successful management of Natterer's bat populations, semi-natural broad-leaved woodland should be retained. Clear felling of large blocks of native broad-leaved woodland should be avoided and conifers should not be used for reforestation. Tree cover along river banks should be encouraged and protected.
ABSTRACT Tree cavities likely vary in their thermal quality for cavity-nesting animals, which could be especially important during winter. We conducted a winter field experiment to test whether cavities vary either in their buffering capacity or in their mean temperature according to predictable characteristics. We found that cavities buffered temperature and that there was a lag effect in temperature that appeared to be related to heating and cooling. Diameter at breast height was the most important variable influencing cavity temperature during the day, with smaller trees warming up more. During the night, diameter at breast height and tree decay class were important, such that larger, live trees cooled down less. Maintaining live trees with cavities in managed forests should be considered in addition to snag retention, because live trees appear to provide warmer structures during winter.
The Tibetan Ground Tit Pseudopodoces humilis is a high-altitude passerine endemic to the Tibetan Plateau. A 4-year study in alpine meadows in Northern Tibet at 4300 m asl demonstrated that rather than using Pika Ochotona spp. holes as previously reported, the birds excavated one nest burrow themselves in spring and another after breeding, which they used for roosting in winter. Both the nesting and winter-roosting burrows comprised a straight tunnel leading to an ellipsoid chamber. There were no significant differences in placement or structural characteristics between the two types of burrows, except that winter-roosting burrows had a significantly smaller entrance diameter. Most burrows were 100–160 cm long and their chambers 20–40 cm deep. Tibetan Ground Tits tended to maximize the thermal benefits of their burrows by adjusting their spatial and structural characteristics in response to local solar radiation and wind regimes. Burrows tended to be oriented towards the sun and away from prevailing winds, presumably to maintain burrow temperature. Longer tunnels could function to save heat from solar radiation or reduce wind-disturbance, while shorter tunnels allow chambers to be warmed sooner in situations where wind potentially reduced soil temperatures. The thermal benefits to the birds of burrow architecture are likely to play a crucial role throughout the year in these extreme alpine environments.
Kiwi possess many unusual features that make them interesting subjects for behavioural study. However, their nocturnal, cryptic nature has meant that studies to date rely on data collected indirectly. Infrared technology has enabled us to observe kiwi directly and here we present the first study of wild brown kiwi (Apteryx mantelli) behaviour by direct observation. We used handheld infrared video cameras to obtain c. 6 hours of video footage of kiwi over 19 months. Kiwi used native forest and exotic pasture habitats while active at night and spent most of their time foraging (75%). Prey capture rates were significantly higher in pasture than forest. The remaining 25% of time was spent walking, vigilant, engaged in comfort behaviours, escaping disturbance, and investigating obstacles. Direct social and courtship interactions were observed rarely. The senses of hearing, olfaction and touch seemed most important to kiwi. Touch was used for investigating terrain and negotiating obstacles. Hearing was used in response to sounds made by observers, conspecifics and other sources. Olfactory search behaviours (OSBs) were used in the direction of these sounds, and olfaction was also apparently used to assess odours on the ground. We observed no behaviours that appeared to be guided by vision. Behavioural repertoire size and diversity increased in winter, due to increases in OSBs towards conspecifics and other odour sources, and rarely observed behaviours. Prey capture rates also increased near-significantly in winter and microhabitat use was more diverse. Female kiwi at our study site had 30% longer bills than males, and probed into soil substrates on average 30% deeper. No other fine-scale behaviours that might reduce competition between kiwi sexes were observed.
The decision where to live has far-reaching fitness consequences for animals. In contrast to most other mammals or birds that use sheltered nest sites, female Bechstein's bats frequently switch day roosts during one breeding season, and therefore must often decide where to spend the day. Selecting the right roost is important, because roost quality, e.g. microclimatic condition, influences survival and reproduction in bats. Although thermal factors are very important for the quality of roosts occupied by bats, whether bats base their day roost selection directly on roost temperature has not been tested in the field. Over one summer, we examined and tested the roost choice of 21 individually marked female Myotis bechsteinii living in one maternity colony. In a field experiment, we allowed the bats to choose between relatively warm versus cold bat boxes, while controlling for site preferences. We expected females to exhibit a preference for warm roosts during pregnancy and lactation to accelerate gestation and shorten the period of growth of their young. Roost occupancy over 160 census days reflected significant temperature differences among 89 surveyed roosts (14 tree holes and 75 bat boxes), and preferences changed with the season. Females significantly preferred cold roosts before parturition, whereas post-partum, they significantly favoured warm roosts. Temperature preferences were independent of the roost site, and thus roost selection was based directly on temperature. Boxes with significantly different daytime temperatures did not differ significantly at night. Consequently, bats would have to spend at least 1 day in a new roost to test it. Information transfer among colony members might facilitate knowledge of roost availability. Access to many roosts providing different microclimates is likely to be important for successful reproduction in the endangered Bechstein's bat.
The success in energy saving in roosting Great Tits (Parus major) is potentially influenced by roost microclimatic characteristics. We tried to learn about the pattern in cavity microclimate
influence on night roosting of birds, under natural weather conditions. An experimental aviary offered two artificial tree-roosts
with different microclimatic conditions which varied according to the outdoor conditions (mainly due to solar radiation) and
microclimate retention capability of roosts. Birds actively explored roosts before the final choice of sleeping site. Two
hours prior to sunset, there were significant differences between the roosts (n=11 adult males tested, each six nights). Selected roosts had higher average temperature (Wilcoxon matched pairs test, P=0.017) and temperature at the time of sunset (P=0.028). Simultaneously, inside temperature decreased slowly (P=0.047). During the night, when birds slept in one of the roosts, the average temperature was higher (P<0.001) and the fluctuation range of temperatures was smaller (P=0.003) there. Moreover, at the morning twilight, the temperature of the occupied roost was higher (P<0.001). Humidity did not have a significant influence at all. The effect of metabolic heating was demonstrated. When birds
slept in the insulated roost (n=30 nights), the indoor average temperature significantly differed from the non-insulated and outdoor temperatures (Kruskal–Wallis
ANOVA, P=0.0001). Selection of an actually warmer and thermally more stable roost according to the course of weather indicates demand
for a wide spectrum of potential roosts in the natural environment.
Analysis of habitat use based on radio-tagged animals presents difficulties inadequately addressed by current methods. Areas of concern are sampling level, data pooling across individuals, non-independence of habitat proportions, differential habitat use by groups of animals, and arbitrary definition of habitat availability. We advocate proportional habitat use by individual animals as a basis for analysis. Hypothesis testing of such nonstandard multivariate data is done by compositional analysis, which encompasses all MANOVA/MANCOVA-type linear models. The applications to habitat use range from testing for age class, effects or seasonal differences, to examining relationships with food abundance or home range size. We take as an example the comparison of habitat use and availability. The concepts are explained and demonstrated on two data sets, illustrating different methods of treating missing values. We compare utilized with available habitats in two stages, examining home range selection within the overall study area first, then habitat use within the home range. At each stage, assuming that use differs from random, habitats can be ranked according to relative use, and significant between-rank differences located. Compositional analysis is also suited to the analysis of time budgets or diets.
The practical analysis of space use and habitat selection by animals is often a problem due to the lack of well-designed programs. I present here the “adehabitat” package for the R software, which offers basic GIS (Geographic Information System) functions, methods to analyze radio-tracking data and habitat selection by wildlife, and interfaces with other R packages. These tools can be downloaded freely on the internet. Because the functions of this package can be combined with other functions of R, “adehabitat” provides a powerful environment for the analysis of the space and habitat use.
We used radiotelemetry to quantify roost switching and assess associations between members of maternity colonies of forest-dwelling big brown bats. Bats remained loyal to small roosting areas of forest within and between years and switched trees often (). For radiotagged bats from the colony in one of these areas, roost-switching frequency was positively correlated with the number of different individuals with which tagged bats shared roosts. We quantified associations between pairs of bats using a pairwise sharing index and found that bats associated more often than predicted when roost and roostmate selection were random but that all tagged bats spent at least some days roosting in different trees, apart from preferred roostmates. Our results suggest that forest-dwelling big brown bats conform to a fission–fusion roosting pattern. Roost switching in forests may reflect the maintenance of long-term social relationships between individuals from a colony that is spread among a number of different trees on a given night. In this fission–fusion scenario, switching between trees, within a local area, could serve to increase the numbers of individuals with which bats maintain associations. We contend that roosting areas in forests are analogous to spatially large roosts in caves, mines and buildings.
All five species of kiwi (Apteryx spp.) are listed as threatened or near threatened, and an important aspect of kiwi conservation is understanding the biology of parasites because of their potential to act as disease vectors and hinder kiwi survival. Although the ectoparasite fauna on kiwis has been categorized, there is a paucity of information on the biology of the kiwi tick, Ixodes anatis, and other parasites found on this unusual avian host. Here we explore the presence of I. anatis in burrows known to be used by North Island brown kiwi, Apteryx mantelli. There was a significant positive correlation between the frequency with which burrows were used by kiwi and both tick intensity and prevalence. The potential consequences of extended use of burrows by kiwi for nesting and tick intensity are discussed. Monthly tick distributions for varying age/sex classes are described as well as age/sex class distribution in different burrow types, with other invertebrates found in burrows also noted. Given the conservation risk for kiwi and the endemic status of I. anatis, understanding the impact of this tick species on kiwi as well as its natural history should be a priority for future research.
In late 2000, five sanctuaries were established on the mainland of New Zealand for the express purpose of protecting populations of five kiwi Apteryx spp. taxa belonging to three species. Conservation management was undertaken at a landscape scale (10,000–20,000 ha) in each sanctuary to improve recruitment of kiwi. This was done by controlling introduced mammalian predators (especially stoats Mustela erminea), and/or by removing eggs and chicks from predation risk, and returning subadults when they were big enough to cope with stoats. Population modelling of the first five years of the sanctuary programme indicated that kiwi numbers in all five sanctuaries would increase as a result of the management. Calculated population increases varied from 0.6% per year at Okarito to 11.3% per year at Moehau, even though predator trapping was more intense at Okarito. The variation from site to site was explained by the widely different inherent productivity of the various kiwi taxa; widely different rates of adult mortality due to the presence or absence of dogs Canis familiaris and ferrets M. furo, the main predators of long-lived adult kiwi; and, local forest conditions affecting predator-prey cycles, and the density of stoats. As a result of this analysis, the management in four of the five sanctuaries has since been modified to try to achieve better overall gains for kiwi within the same operating budget.
Certain native species are able to tolerate the urban landscape to the point where they are sometimes found in higher abundance in cities than they are in the surrounding natural vegetation. To improve understanding of the resource requirements of Australian parrots, we investigated the seasonal abundance and habitat use of 13 species in different landscape units in the major urban centre of Sydney, Australia. The urban landscape was divided into four urban zones and 528 surveys were conducted over a period of two years throughout four habitats of remnant vegetation, golf courses, street scapes and recreational parks, as well as the surrounding natural landscape, during both breeding and non-breeding seasons. Significant seasonal differences in abundance existed for two granivorous and one nectarivorous species. Abundance was significantly higher in the outer urban zone than in the non-urban zone and species assemblage differed significantly between all urban zones and the non-urban zone during the breeding season but only between the city and non-urban zone during the non-breeding season. Remnant vegetation was also characterised by a significantly different community assemblage to other habitats during the breeding season. Understanding how fauna utilise the urban landscape, particularly high profile fauna such as parrots, has the potential to assist in both management and conservation of urban diversity.
Individuals in a number of bird species have the opportunity to maintain contact with their mates during nonbreeding periods. This contact may be important to synchronize the partners' reproductive cycles before breeding begins. As a first step toward exploring the function of pair bond maintenance in non-breeding birds, I studied the behavior of three pairs of Pileated Woodpeckers (Dryocopus pileatus) and an unpaired male at roost sites during autumn. At dawn and dusk, paired individuals exchanged visual, vocal, and other acoustical signals identical to those given during the breeding season. Demonstration tapping away from a nest is reported here for the first time. The possible function of these behaviors may be related to monitoring the partner's condition and investing in the pair bond to enhance future reproductive success.
We analyze environmental determinants of roost
site selection by tree gleaning passerines wintering in a
Mediterranean montane oakwood at a craggy area of high
variation in altitude and hill-shading pattern.We hypothesize
that in temperate latitudes of cold winter climate, birds
should spend the night in areas of low altitudes, higher
temperatures, and higher solar radiation in order to minimize
thermoregulation costs during resting time and to improve
foraging conditions just before and after roosting. We study
night occupation of woodland locations by the presence of
feces in 159 wooden nest boxes (i.e., under identical controlled
roosting situations). We employ GIS methods to
quantify solar radiation at each location surrounding the nest
boxes and data loggers to measure air temperature in the
field. Birds prefer to roost in forest patches with higher solar
radiation, where the period of light available for foraging is
extended and thermoregulation costs during daytime are
minimized. They also selected woodland patches with taller
trees, a pattern consistent with their foraging preferences for
trunks and branches. Other environmental variables played a
negligible role in determining the selection of roost sites.
Here, we show, for the first time, the importance of sun
radiation determining where to spend the night in wintering
birds and call attention on considering the thermal space in
forest management. Forest management should preserve
woodland patches with taller trees more exposed to solar
radiation to enhance winter habitat suitability for birds in
these Mediterranean oakwoods.
The results of a radio-tracking study of the uses of den trees by Leadbeater's possum (Gymnobelideus leadbeateri McCoy) at Cambarville in the mountain ash (Eucalyptus regnans) forests of the Central Highlands of Victoria, south-eastern Australia, are described. Animals were radio-tracked for three periods of 5-20 days in July 1990, November 1990 and July 1991. A total of 14 individuals was tracked and they occupied 11 different trees with hollows on the 10-ha study site. Preliminary findings showed that some animals moved between hollows in different trees, and most animals used two or more trees. The distances between utilised trees usually exceeded 50 m. Possible reasons for the den-swapping behaviour include attempts to either or both relieve burdens of ecto-parasites and to reduce the risk of predation. There were several examples, in each of the three radio-tracking periods, of two or more radio-collared adult breeding female animals simultaneously co-occupying the same nest tree. This result was different from some of the general findings of an earlier study of G. leadbeateri at Cambarville.
Vagrant, non-breeding common ravens,Corvus corax, inhabiting the forested mountains of Maine are specialized to feed on rich but ephemeral carcasses of large mammals during the harsh winter months. The foraging and roosting behaviour of free-ranging ravens were studied during the winters of 1988–1990. Ravens quickly assembled at carcasses, and into communal roosts. Six lines of evidence indicate that these roosts function as information centres. (1) Roosts comprised both knowledgeable and naive foragers. (2) Departures from roosts were highly synchronized, with most members departing in one direction. (3) Direction of departure often changed from day to day. (4) Birds made naive of food sources (by being withheld from the wild and then allowed to join roosts) followed roost-mates to new feeding sites, whereas control birds held and released outside of roosts rarely found the local food bonanzas. (5) Birds made knowledgeable of food sources (by being released at new carcasses) joined roosts and led roost-mates to the food on three of 20 occasions. (6) The same individuals switched leader and follower roles depending upon their knowledge of feeding opportunities. Although ravens may form roosts at traditional areas (near stable food sources) that are used for many years, the ravens in Maine frequently shifted roost sites to be near newly discovered carcasses. Information exchange at roosts principally occurred on the night of, or the night before, the roost shift. Social soaring displays assembled birds from a wide area and were associated with mass movements to new roosts formed at nearby food.
The endangered pygmy blue tongue lizard, Tiliqua adelaidensis, occupies spider burrows in a population near Burra, South Australia. In each of twelve 20 x 20 m plots at that population, we added 36 artificial burrows, providing about a ten fold increase in suitable burrows for lizards. Over three surveys during the spring and summer of 2001/2002 there were significant increases in lizard numbers in the experimental plots relative to the controls, both for adult lizards and for new recruits after clutches were produced. This local increase in population density may be due to lizards locating suitable burrows more easily where burrow numbers were supplemented. The increased availability of high quality burrows may also reduce mortality among lizards searching for suitable burrows. Additional burrows also led to an increase in local density of a burrow-dwelling centipede that is a potential predator of lizards, but there was no evidence of predation, and any negative predation impact was outweighed by the beneficial effect of providing more burrows. Overall the results suggest that adding artificial burrows could enhance local population density and recruitment success, and that this could be a valuable tool in the conservation management of this endangered species.
Numerous studies describing habitat preferences and anti-predation behaviour in the grey partridge (Perdix perdix) focus on the daytime. This is the first study analysing nighttime behaviour by means of thermography. In total 640 partridges, clearly avoiding field boundaries as roosting sites to roost in the open field, were observed. Comparing day- and night-time behaviour of partridges they not only perceive a 'predation risk landscape' but moreover a 'predation risk schedule' resulting in a circadian shift in anti-predation strategies. Furthermore, partridges were ascertained to roost in tighter groupings on darker nights. I hypothesize that the efficiency of visual detection decreases with deteriorating light conditions — confirmed by a decreasing flight initiation distance — and partridges huddle closer together fearing such an insecure situation. The preference to roost in smaller subunits within one covey is explained by a more efficient predator detection compared to tight groupings. In contrast to the day-time behaviour, at night the first choice as an escape movement is flying. Altogether partridge behaviour in winter at night was found to be well adapted to predator avoidance and energy economy, explaining the lower predation rates during the 'covey season' compared to the spring phases of dispersal, laying and incubation.
We assessed the value of communal roosting for mating and territory acquisition in nonbreeding red-billed choughs, Pyrrhocorax pyrrhocorax . Between 1991 and 1996 we surveyed all communal roosts, breeding territories and vacant nest sites in an area of 250 km2in Los Monegros (northeast Spain), as well as other communal roosts in the surrounding 500 km2from 1987 to 1996. Main roosts were used traditionally and throughout the year and gathered more choughs than subroosts, which were used only during the nonbreeding season. Nonbreeding choughs were socially segregated in these roosts according to their age and breeding prospects. Compared with random potential roost sites, main roosts included more first-year birds and were in areas of higher breeding density. Subroosts were mainly joined by choughs of breeding age (at least 2 years old) whose morphology (males) and body condition (females) were similar to those of established breeders, and were in areas with breeding densities as high as around main roosts but with more available nest sites. Nonbreeding choughs that used main roosts later used subroosts, while the converse was rare. More choughs joining subroosts acquired mates than those joining main roosts. Choughs mostly paired with roostmates but also with widowed territorial breeders. Finally, choughs from subroosts acquired territories closer to the roost than those who mated in main roosts, supporting the hypothesis that subroosts reduce the costs of mating and territory acquisition.
Mainstream conservation has been long dominated globally by the protected area paradigm. This approach has been widely challenged in recent years, and new conservation initiatives have emerged. The situation is mirrored in New Zealand, where ongoing biodiversity loss has prompted reappraisal. Within this context, we highlight the plight of kiwi, focusing on Northland and efforts there to (re)make space for this iconic bird which is at risk of extinction. While the state has primarily responded by fortifying "islands" on public conservation land, Far North communities are working in a variety of ways and localities, both within and beyond "the fortress", to secure a future for the "people's bird".
DNA-based sex tests now exist for many avian species. However, none of these tests are widely applicable to ratites. We present DNA sequence data for a locus that is W chromosome-linked in the kiwi, ostrich, cassowary, rhea, and emu. At the amino acid level, this sequence has significant homology to X-linked genes in platyfish and Caenorhabditis elegans. Polymerase chain reaction (PCR) primers designed to this locus allow the assignment of sex in all species of living ratites.
Kiwi (Apterygidae: Apteryx spp.) are traditionally assumed to detect their soil-dwelling invertebrate prey using their sense of smell. The unique position of the nares at the tip of the bill and the enlarged olfactory centres in the brain support this assumption. However, studies designed to show the importance of olfaction in prey-detection by Apteryx have provided equivocal results. Another family of probing birds, the Scolopacidae, detect their buried prey using specialised vibration and pressure-sensitive mechanoreceptors embedded in pits in the bill-tip. We found that aspects of the foraging patterns of Apteryx mantelli are like those of scolopacid shorebirds, suggesting that Apteryx may be using a similar prey-detection mechanism. We examined specimens of all five Apteryx species and conducted a morphological and histological examination of the bill of A. mantelli. We discovered that Apteryx possess an arrangement of mechanoreceptors within pits similar to that in Scolopacidae species and may therefore be able to localise prey using a similar vibrotactile sense. We suggest that this sense may function in conjunction with, or be dominant over, olfaction during prey-detection. The Apterygidae and the Scolopacidae are members of the two different super-orders of birds: the Paleognathae and the Neognathae, respectively. Therefore we cite the similar bill-tip anatomy of these two families as an example of convergent evolution across a deep taxonomic divide.
The white-throated Dipper (Cinclus cinclus) is unique among passerine birds by its reliance on diving to achieve energy gain in fast-flowing waters. Consequently, it should have evolved behavioural adaptations allowing responding directly to runoff patterns (one of the assumptions of the Natural Flow Regime Paradigm-NRFP). In this study (October 1998-August 2001), we investigated how behavioural and energy use strategies in Dippers might vary under the natural flow regime of snowmelt-dominated streams in The Pyrénées (France) where natural flow regime is highly seasonal and predictable. We recorded time spent in each of 5 behavioural activities of ringed birds to estimate time-activity budgets and derive time-energy budgets enabling the modelling of daily energy expenditure (DEE). Annual pattern in 'foraging' and 'resting' matched perfectly the annual pattern of the natural regime flow and there was a subtle relationship between water stage and time spent 'diving' the later increasing with rising discharge up to a point where it fell back. Thus, time-activity budgets meet the main prediction of the NRFP. For males and females Dippers, estimates of feeding rates (ratio E(obs)/E(req)=observed rate of energy gain/required foraging rate) and energy stress (M=DEE/Basal Metabolic Rate) also partly matched the NFRP. Maximum value for the ratio E(obs)/E(req) was registered in May whilst M peaked in spring. These ratios indicated that Pyrenean Dippers could face high energy stress during winter but paradoxically none during high snowmelt spates when food is expected to be difficult to obtain in the channel and when individual birds were observed spending ca 75% of the day 'resting'. Annual pattern in DEE did not match the NFRP; two phases were clearly identified, the first between January to June (with oscillating values 240-280 kJ d(-1) ind(-1)) and the second between July and December (200-220 kJ d(-1) ind(-1)). As total energy expenditure was higher during the most constraining season or life cycle, we suggest that energy management by Dippers in Pyrenean mountain streams may fit the 'peak total demand' hypothesis. At this step of the study, it is not possible to tell whether Dippers use an 'energy-minimisation' or an 'energy-maximisation' strategy.
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