It takes two to tango, but not two pairs! Rare record of two reintroduced pairs of vinaceous-breasted Amazons sharing the same nest-box

Secondary cavity-nesting birds can utilize artificial nest boxes provided by humans for breeding, making nest boxes important approaches for attracting birds. Artificial nest boxes are therefore widely used in fields such as ornithological research and avian diversity conservation. Under natural conditions, the location of nests often affects the reproductive success of birds. Therefore, understanding the impact of nest box hanging positions on the breeding success of secondary cavity-nesting birds is of great significance for guiding the placement of artificial nest boxes. In this study, we explored the potential factors, including nest-box location, that affect the reproductive success of the russet sparrow (Passer cinnamomeus) by monitoring the nest-site characteristics and reproductive parameters such as clutch size and brood size of those breeding in artificial nest boxes near Dongzhai National Nature Reserve, Henan, China, from April to July 2024. Russet sparrow nesting in boxes on coniferous trees and utility poles showed no significant differences in clutch size, hatching rate, brood size, pre-laying nest-abandonment rate, and whether the breeding was ultimately successful. Nests with earlier egg-laying dates had larger clutch sizes, higher hatching rates, and greater brood sizes. However, the number of fledglings and fledging success were not affected by laying date, and fledging success was not affected by either the distance from the nest site to the nearest road, or the brood size. Both larger brood size and greater distance from the nearest road were associated with increased numbers of fledglings. Furthermore, russet sparrows nesting in boxes on coniferous trees produced significantly more fledglings and exhibited higher fledging success compared to those nesting on utility poles, suggesting that nest boxes' hanging position may influence russet sparrow reproductive success. These findings not only supplement existing ecological data on russet sparrow reproduction in artificial nest boxes but also provide important insights for avian conservation practices, highlighting the necessity of fully considering hanging position when deploying artificial nest boxes for birds.

The overwhelming demand of deadwoods outside protected areas has not given deadwoods enough time to remain standing for the formation of the tree cavities by birds and other natural agents. Consequently, cavity adopter and large-bodied species face difficulties in finding and establishing acceptable nest sites. The focus of biodiversity conservation has been mainly within protected area systems, and less attention has been given to areas outside protected areas despite the fact that these areas support a bigger proportion of bird community. A high pace of deadwood loss on the entire landscape on the southern slopes of Mount Kilimanjaro is an irreversible situation in which is increasingly becoming a growing concern for the conservation of biodiversity beyond protected areas. Here, we investigate what extent deadwoods have in providing nest sites among cavity-nesting birds. We do this through observations and by placing artificial nest boxes on trees within three different land-use types. We found that deadwood volume and number of natural tree cavities were lower at coffee plantations as compared to mixed farming areas and Kilimanjaro National Park (KINAPA). Likewise, tree cavity positions from the ground were higher at coffee plantations than in other two land-use types. However, application of artificial nest boxes reveals that a good number of larger artificial nest boxes had greater occupancy, as did boxes placed at higher positions on trees from the ground at coffee plantations and mixed farming areas than at KINAPA, suggesting a shortage of natural cavity-nesting sites for larger birds and an avoidance of nest predation or human disturbances, respectively. Therefore, provision of artificial nest boxes could offer nesting opportunities for a range of cavity-nesting birds if designs and constructions take into consideration all possible factors that might hinder their occupation by cavity-nesting birds. In this manner, application of cavity nest boxes could be a vital alternative tool for conservation of cavity-nesting birds beyond boundaries of protected areas.KeywordsCavity-nesting birdsTree civitiesDeadwoodMount Kilimanjaro National ParkArtificial Nest Boxes as conservation toolsConservation

Artificial (Wooden) nest boxes were successfully adopted by Spotted Owlet (Athene brama) and Common Myna (Acridotheres tristis) which accomplished egg laying in 9.80 and 74.50% boxes, out of total 51 boxes, installed at eight different sites at one location. Egg laying by Common Myna was accomplished repeatedly for second and third time in 23.53 and 3.92% nest boxes respectively after successfully raising the previous brood. Breeding success of 35.71 and 77.86% was achieved in Spotted Owlet and Common Myna. None of the birds adopted and accomplished breeding in 33 boxes installed at two different sites, 15 and 18 boxes at each site, at another location owing to the dominance of Barn Owl, Tyto alba and Tree mouse, Vandeleuria oleracea dumeticola at the respective sites. Timing and site of installation served as contributing factors while predation and parasitism acted as limiting factors in nest box breeding. Higher breeding performance of Common Myna was recorded in artificial nest boxes than in natural cavity nesting.

Conservation biologists have begun to apply general principles of animal behavior to solve conservation problems. Four major edited volumes and a number of reviews published in the last decade have proposed theoretical and empirical links between behavior and conservation (see the Animal Behavior Society's Conservation Committee website: http://www.animalbehavior.org/ABS/Conservation/). To strengthen this multidisciplinary collaboration, it is essential for conservation biologists to understand the types of questions addressed by the field of animal behavior (proximate and ultimate) and the implications of these questions for conservation biology, the conservation literature, and recovery teams. Conservation biologists may be unfamiliar with the jargon of behavioral biologists, but lack of knowledge is no excuse to ignore animal behavior. We believe that behavioral biologists have much to contribute to conservation biology and that by involving conservation behaviorists too late in conservation plans or recovery teams, we will continue to suffer avoidable setbacks, waste precious funds, and lose priceless animals. The Nobel Prize-winning ethologist Nikko Tinbergen first outlined two main types of questions that could be asked about any behavioral phenomenon. Proximate questions focus on behavior's development or immediate causation. Ultimate questions focus on behavior's evolutionary history or current adaptive utility. Thus, by definition, conservation behavior should be viewed as a field of study that encompasses multiple levels and incorporates a variety of disciplines, including genetics, physiology, behavioral ecology, and evolution. Understanding social relationships that lead to fitness (ultimate questions) has clear links to conservation. For instance, infanticide by males is an adaptive reproductive strategy that needs to be considered in the management of some species, such as bears and African lions. Managers typically view males as superfluous and model populations based on the number of breeding females. However, in species where males kill offspring sired by other males to encourage females to come into estrus and mate with them, any subsequent social disruption has a large effect on population size. Normally adaptive reproductive strategies have other consequences when individuals encounter anthropogenic changes. For instance, as water quality declines, it becomes more difficult for fish that use visual signals to make adaptive mate-choice decisions. As a result, fish may hybridize and suffer reduced individual fitness and the population itself may decrease. Some argue that ultimate questions are most important for conservation because they link variation in behavior with fitness. However, understanding how proximate processes affect survival is also crucial. For example, we know that training captive-reared animals to recognize predators may increase post-release survival. Yet further studies on the developmental contexts, presence of sensitive periods, and types of experiences required may yield more efficient and effective training programs. From a management perspective, searching for the fitness consequences of behavioral responses may provide insights into the impacts of certain human activities on wildlife, but this does not necessarily translate into conservation gains. We believe that mechanistic research will increase the predictive power of our conceptual and mathematical models. In general, by searching for mechanisms, we search for a deeper understanding of how animals make adaptive decisions. And by taking this sort of uniquely behavioral approach, we may gain important information about how to better manage populations. For instance, a strategy to better manage the effects of tourists on wildlife is to understand the proximate mechanisms underlying the response of animals to humans. We recognize the importance of documenting population-level responses to human disturbance. However, to reduce negative effects on wildlife and increase the number of species that can be viewed by tourists, managers must know how to control rates of human visitation to protected areas. To predict habitat use in areas with different levels of human visitation, we need to determine the number of tourists per unit time and area that do not negatively affect the frequency of resource use (e.g., feeding, nesting, and roosting sites) by target species. In due course, we must identify behavioral indicators of disturbance and develop an understanding of the behavioral mechanisms that explain the tolerance of some, but not all, species to human disturbance. It is essential to recognize these qualitatively different questions along with their applied implications when assessing the value of conservation behavior. Habitat loss is a huge threat to biodiversity, yet habitat improvements are often made without regard to how species perceive the habitat (a proximate question) or thebehavioral consequences of such intervention. For instance, adding nest boxes (i.e., increasing nesting habitat) is often done to increase reproductive success for cavity-nesting birds. If the artificial nest boxes are too close together, however, there may be unintended social consequences. Clumped nest boxes lead to an increased rate of egg dumping and conspecific brood parasitism, both of which reduce reproductive success. Hence, without attention to behavioral details, such well-intentioned habitat “improvement” programs may waste valuable funds and have detrimental effects on the population underrecovery. To develop more effective programs, conservation biologists must fully recognize the value of integrating proximate and ultimate behavioral studies. In recent years, this lack of integration has generated resistance toward increasing the diversity of the conservation behavior literature and has constrained the use of behavioral data by recovery teams. Based on our experiences and those of many of our colleagues, it is difficult to publish papers on conservation behavior, a problem not restricted to any particular journal. When manuscripts on conservation behavior are submitted to conservation journals, negative reviews may highlight a lack of immediate applicability or a lack of a direct link between behavioral responses and fitness (e.g., reproductive output, survival rates). Yet general questions about proximate behaviors that affect survival, mortality, or population size are all topics that are explicitly relevant to conservation biology. When conservation behavior manuscripts are submitted to behavior journals, they may be rejected because of an apparent lack of theoretical framework, or, if they are accepted, authors are asked to remove most references to conservation. However, conservation behavior itself can be theoretical. For example, predicting the behavioral mechanisms underlying the vulnerability of a species to human impacts and predicting how long antipredator behaviors persist following isolation from predators are behavioral considerations that are explicitly, theoretically motivated. A far greater threat to species survival than the difficulties of publishing conservation behavioral findings is the tendency of recovery teams to wait too long to integrate behavioral biologists into their efforts. Such oversights appear to be related to a lack of understanding of how behavioral studies are conducted. For instance, an exciting and promising line of conservation behavior research seeks to increase reintroduction success by evaluating the antipredator abilities of animals prior to release and then following their fates. If individuals with inferior antipredator behavior are preyed upon more frequently than those with superior abilities, then pre-release training may be used to prepare animals for release. For years, ethologists have used simple models, taxidermic mounts, and playback of sounds through speakers to study the perceptual and assessment abilities of a variety of species. Through the use of simple stimuli, these techniques allow one to learn about how animals assessrisk. Although managers must make tough decisions about what can be done with animals prior to release, they must think critically about how much they can learn from these studies to improve success rates. The recovery programs for black-footed ferrets (Mustela nigripes) and golden lion tamarins (Leontopithecus rosalia) provide evidence that fully integrating behavioral biologists into the recovery process can make a difference. In both cases, paying attention to the environment these species were reared in and providing pre-release behavioral enrichment was essential for ultimate success. In the long run, it may be more cost-effective to incorporate behavioral biologists at the outset of captive breeding and reintroduction programs rather than to wait until a “problem” emerges, animals die, and precious funds are spent. Conservation behavior will not provide the solutions to all conservation problems, but we conservation behaviorists need to show how useful a behavioral perspective can be. By understanding the type of questions conservation behavior can address, one can better evaluate how and when wildlife conservation could benefit from behavioral knowledge. Addressing both proximate and ultimate questions of conservation behavior is essential to improving our management decisions. Two research areas in particular will not only help bridge the gulf between conservationists and behaviorists but will also help research on conservation behavior to produce specific conservation outcomes. First, we must develop predictive models of behavior that are accessible to wildlife managers. Advances have been made in foraging theory and modeling habitat selection, wherein animal decisions have been modeled with increased sophistication. However, the sophistication that comes with deeper understanding may impede application by its complexity. Behavioral biologists should strive to make their models accessible to others by identifying specific behavioral mechanisms. These mechanisms should be the basis of bottom-up models that predict the behavior, movement, habitat use, and distribution of species of conservation concern. Second, we must develop an ultimate understanding of how and why species are vulnerable to human impacts. Study of conservation behavior is much more than simply documenting whether or not humans affect wildlife. The explosion in comparative biology and macroecology in the past decade offers a framework for future advances in predictive evolutionary models. Future studies should examine how variation in life history and natural history explains variation in proneness to extinction, tolerance to human disturbance, and tolerance to invasive species at local scales. Ignoring the diversity and methods of modern behavioral biology places conservation-dependent animals at peril. Although we are excited that some wildlife managers and conservation biologists appreciate the expertise offered by behavioral biologists, we believe that many still fail to appreciate the importance of proximate mechanisms. Some pigeonhole behavioral research as too species-specific and fail to recognize that behavioral biologists can produce generalizable and predictive models. With an increased appreciation of what conservation behaviorists have to offer, and a fundamental integration of them into recovery teams, we believe that future recovery efforts will be more successful and cost-effective, and that the exciting integrative field of conservation behavior will prosper.

Five artificial nest boxes for hornbills were erected along the river in the Lower Kinabatangan Wildlife Reserve, Malaysia in 2013. The nest boxes were built by a French non-government organization (i.e HUTAN/KOCP) and two zoos from United Kingdom and France (i.e. Chester Zoo and Beauval Zoo). After the artificial nest boxes were erected in the forest, a comparative study between natural cavities and nest boxes was conducted from September 2014 to February 2015, to measure internal humidity and temperature. It is assumed that these two parameters are important factors for nest box occupancy. Data loggers (RHT 10 USB EXTECH) were used to measure temperature and humidity inside and outside of the natural cavities (n = 3) and artificial nest boxes (n = 4). For nest boxes, internal temperature ranged from 21.8 to 35.0°C while internal humidity ranged from 40.1 to 99.4%. On contrary, internal temperature for natural cavity remained low (from 22.5 to 27.5°C) while its internal humidity ranged from 95.9 to 100%. Camera traps recorded several species of hornbills such as Rhinoceros (Buceros rhinoceros), Wrinkled (Rhabdotorrhinus corrugatus), Bushy-crested (Anorrhinus galeritus), and Oriental Pied (Anthracoceros albirostris convexus) hornbills that visited the nest boxes. Rhinoceros Hornbill had attempted to seal the entrance of the artificial nest boxes while Oriental Pied Hornbill was the only species that occupied one of the nest boxes. These responses indicate that nest boxes could play an important role in providing alternative nesting sites for hornbills.

The importance of artificial nest boxes for North Island saddlebacks (Philesturnus carunculatus rufusater) on Tiritiri Matangi Island has increased significantly, suggesting that “natural” nesting cavities are now a limited resource for this growing population. The design and position of artificial nest boxes directly affects the likelihood of saddleback use for nesting: small boxes (0.005 and 0.0lm3) with large (140–160 mm high) north facing openings had the highest probability of being used. One of the disadvantages of using artificial nest boxes in conservation management is the potential for parasite build‐up. Two species of mesostigmatid mites were found in the artificial nest boxes used by saddlebacks on Tiritiri Matangi Island. One was an undescribed species of Dermanyssid mite the other was Ornithonyssus bursa, the fowl mite. The numbers of mites detected increased over the saddleback nesting cycle from September to December. However, our results strongly suggest that, for saddlebacks, no negative correlations exist between mite abundance and chick weight, fledging date, or the number of fledglings produced. Mite abundance was extremely variable and did not correlate with nest box temperature or relative humidity.

Artificial nest boxes are critical nesting sites for secondary cavity-nesting birds; however, they are often placed near roadways and in urban areas that experience noise pollution and other human-caused stressors. Recent correlative studies document both negative and positive influences of noise pollution on reproductive success. Additionally, observational studies have not determined which stage of the breeding process is most vulnerable to noise pollution-settlement, incubation, and/or provisioning. Here, we controlled for possible effects from non-random settlement and eliminated potential effects of roadways, such as collisions and chemical and light pollution, by experimentally introducing traffic noise into nest boxes after clutch initiation in two secondary-cavity nesting bird species. We found no evidence for an influence of noise on clutch size, brood size, number of fledglings, or overall nest success in western bluebirds (Sialia mexicana). In contrast, we found that ash-throated flycatcher (Myiarchus cinerascens) nests exposed to noise had lower reproductive success than quiet nests due to higher rates of abandonment at the incubation stage. Our results match recent research demonstrating that ash-throated flycatchers avoid energy-sector noise in their nest placement and, when they do nest in noise, experience stress hormone dysregulation and fitness costs. The lack of a response among western bluebirds differs from reported declines in reproductive success due to exposure to energy-sector noise; however, the absence of a response matches the response seen in other species using an in-box noise playback experiment. These results suggest that in-box noise exposure experiments may be appropriate for assessing noise impacts at the nest, and through some pathways (e.g., direct effects of noise on nestlings), but do not capture other ways in which noise can negatively affect birds during the breeding season that may ultimately cause declines in fitness. Additionally, although manipulative experiments that examine the influence of a single anthropogenic stressor on a single life stage can help reveal causal pathways, urban and other human-dominated environments are characterized by many stressors and future studies should seek to understand how noise interacts with other stressors to impact birds and other wildlife. Finally, in light of mounting evidence demonstrating declines in reproductive success due to noise, our results suggest that nest box placement near roads may be counterproductive to efforts to bolster population densities of some species.

Reduced breeding success in nest boxes for great tits (Parus major) and Eurasian blue tits (Cyanistes caeruleus) in highly urbanised areas: An ecological trap?

1. Interspecific interference competition for nest-sites among cavity-nesting birds can have important effects on reproductive fitness and the distribution of competing species. 2. We observed interference at nest-sites in free-living populations of the endangered Gouldian finch (Erythrura gouldiae) and sympatric long-tailed finch (Poephila acuticauda), and also experimentally tested the relative strength and effect of interference at nest-sites in captive populations. 3. Levels of competitive interference at nest-sites in the wild were high for Gouldian, but not long-tailed finches, and interference frequency was inversely related to Gouldian finch reproductive success. High levels of interference conferred reduced fledging success but did not affect offspring condition. 4. Captive experiments corroborated the field data, also demonstrating fitness costs of interspecific competition, and that long-tailed finches dominated resources under standardized conditions. 5. Such asymmetrical competition dynamics are likely to constrain reproduction in Gouldian finch populations, potentially affecting recruitment and hindering the recovery of remaining populations of this endangered species.

ABSTRACTHatching success in birds is influenced by the temperature and turning rate of the egg, but our understanding of the environmental factors that effect incubation temperatures and egg turning rates in birds is limited. Especially little is known of these effects for species that nest in burrows or crevices, such as the Cassin's auklet (Ptychoramphus aleuticus). On Southeast Farallon Island, California, USA, a subset of the Cassin's auklet (hereafter auklet) population nest in artificial nest boxes. The nest boxes are above ground and made out of a single layer of plywood. Temperatures in unshaded nest boxes can increase significantly with high ambient temperatures (to >35° C). Shaded structures put on top of occupied nest boxes help mediate nest box temperatures, but the effects of elevated temperatures on auklet incubation behaviors and egg viability remain equivocal. We used egg data loggers to measure the temperatures and turning rates of auklet eggs in natural burrows, shaded nest boxes, and unshaded nest boxes on Southeast Farallon Island. Nest box (13.93 ± 1.26° C) and egg (37.43 ± 1.92° C) temperatures were highest and most variable in unshaded nest boxes. Mean hourly egg turning rate was 2.11 ± 2.02 turns/hour and turning rates were greater at night. Egg turning rates also varied with fluctuating nest and egg temperatures, being positively correlated with nest temperatures during the day and negatively correlated with egg temperatures during the night. Our results suggest that nest box design can influence incubation behaviors of breeding birds. As seasonal temperatures and the number of extreme heat events rise, understanding the impacts of temperature on auklets nesting in artificial nests can have positive implications for conservation and management of the species, such as implementing improved artificial nest box designs to prevent overheating of burrow nesting seabirds. © 2015 The Wildlife Society.

Negative effects of artificial nest boxes on birds: A review

This paper describes the approach and initial results of a trial utilizing artificial nest boxes to support the avian population for seed disbursal for vegetation restoration purposes. The study site is an onshore gas receiving facility (ORF) concession area, located within a globally recognised Key Biodiversity Area (KBA). By applying the mitigation hierarchy, the company has limited the residual impact on natural habitats and is enhancing the forest estate through active and passive forest restoration. Historic land use has resulted in a paucity of natural breeding spaces for cavity-nesting birds, potentially limiting avian abundance and diversity. Artificial nesting boxes are a common technology in newly established and managed woodlands and are considered highly effective at supporting avian conservation objectives. Their effectiveness is correlated with imitating the size, shape and climatic conditions of natural cavities. Hence a trial was necessary to identify the most suitable design for the conditions and species encountered in the project location. Sixty-five nest boxes were installed with the design, construction material and entrance diameter among variables trialled. Those crafted from a mud-cement mixture showed the greatest durability, although those constructed from solid wood performed adequately and were easier to construct. Nest box occupancy after a year or less remained low; only three of the 65 boxes installed show clear or potential signs of use. Potential occupants showed preference for a "standard" box design. No preference for entrance size or construction material could be construed. Arthropods were identified residing in the boxes on 10 occasions. Their impact on bird occupancy is uncertain, however insects may hasten the destruction of wooden boxes and render the box uninhabitable for nesting birds or hatchlings. The project also encountered unexpected losses and severe damage to 25 nest boxes, 20 of which were unable to be located and hence could not be assessed. Although very early in the project, recommendations from these monitoring results can enhance the effectiveness of the technology for other users. Recommendations to improve occupancy include increasing the installation height, checking the correct orientation for the location and minimising the opportunity for eusocial insects to access the nests. Boxes should be securely fixed in place, preferably with two methods to allow for functional redundancy. Finally, engagement with local communities is a critical consideration; projects engaging in the use of this technology should not overlook the need to identify and address negative perceptions or misunderstandings that may negatively affect their use.

Large trees support unique habitat structures (e.g. hollows) that form over centuries and cannot be provided by small trees. Large trees are also declining in human‐modified landscapes worldwide. One restoration strategy gaining popularity involves adding nest boxes to smaller trees to replicate natural hollows. However, limited empirical research has tested how hollow‐nesting fauna responds to the presence of nest boxes. We asked: can the addition of nest boxes increase tree visitation by hollow‐nesting birds? We conducted a before‐after control‐impact (BACI) experiment using 144 nest boxes and 96 sample trees comprised of three sizes (small [20–50 cm dbh], medium [51–80 cm], and large [>80 cm]) and located in four landscape contexts (reserves, pasture, urban parklands, and urban built‐up areas). We recorded a significant increase in hollow‐nesting bird abundance and richness at large trees after nest box additions. However, the same response was not observed at medium, small, or control trees. We also recorded nonsignificant increases in hollow‐nesting bird abundance and richness at trees in modified landscapes after nest box additions compared to trees in reserves and control trees. Our results suggest that adding nest boxes to smaller‐sized trees may not attract hollow‐nesting birds. Therefore, nest box management strategies may require re‐evaluation as it is often assumed that hollow supplementation will attract hollow‐using fauna and sufficiently ameliorate the loss of large, hollow‐bearing trees. We advocate that large tree retention remains crucial and should be prioritized. Large trees could be effective target structures for habitat restoration, especially in modified landscapes.

The use of artificial nest boxes has led to significant progress in bird conservation and in our understanding of the functional and evolutionary ecology of free-ranging birds that exploit cavities for roosting and reproduction. Nest boxes and their improved accessibility have made it easier to perform comparative and experimental field investigations. However, concerns about the generality and applicability of scientific studies involving birds breeding in nest boxes have been raised because the occupants of boxes may differ from conspecifics occupying other nest sites. Here, we review the existing evidence demonstrating the importance of nest box design to individual life-history traits in three falcon (Falconiformes) and seven owl (Strigiformes) species, as well as the extent to which publications on these birds describe the characteristics of exploited artificial nest boxes in their Methods sections. More than 60% of recent publications did not provide any details on nest box design (e.g. size, shape, material), despite several calls >15 years ago to increase the reporting of such information. We exemplify and discuss how variation in nest box characteristics can affect or confound conclusions from nest box studies and conclude that it is of overall importance to present details of nest box characteristics in scientific publications.

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