Nightjar diversity and microhabitat use in Nechisar National Park,Ethiopia

Knowledge of the distribution and ecology of East African nightjars is, to a large extent, unknown. We collected ecological information on the diversity and microhabitat use of nightjars in Nechisar National Park in January 2015 by executing field captures and observations. We also attempted to find a live specimen of the Nechisar Nightjar Caprimulgus solala. During the course of 18 nights we observed five nightjar species, captured 49 individuals and observed that nightjars were closely associated with protective landscape elements. In spite of the intensity of our survey, we were not able to find a living specimen of the Nechisar Nightjar, which could indicate the species is either migratory or extinct.     

A field survey to investigate why nightjars frequent roads at night

Nightjars throughout the Afrotropical Region regularly frequent roads at night and during the twilight of dusk and dawn. Most species exhibit this behaviour and numerous individuals are killed by road traffic. Many theories have been advanced to explain the presence of nightjars on roads at night, but very little fieldwork has been carried out to test them. For a period of a year we carried out a weekly survey of nightjars on a selected road network near Harare in Zimbabwe. All nightjar encounters were documented in relation to variations in road surface, road width, adjacent habitat, arc of sky visible and other variables, such as the time of night, moon phase and weather conditions. None of these factors provided a complete explanation for the presence of nightjars on the roads surveyed. Neither were any of the nightjars seen dust bathing, taking grit or picking up insects from the road. Many were seen actively hunting flying insects, especially at dusk, and palpation of the stomachs of those caught confirmed that they had fed well during the evening hours. They were clearly using the road as an observation platform for hunting during the first few hours after sunset and then as a convenient place for resting and digesting. A nightjar sitting on an open road is certainly in a good position to see flying insects silhouetted against the twilight sky.     

Comparison of the two rupicolous nightjars: the Afrotropical Freckled Nightjar Caprimulgus tristigma and the Neotropical Blackish Nightjar C. nigrescens

The Freckled Nightjar Caprimulgus tristigma and the Blackish Nightjar C. nigrescens are widespread and common within their rupicolous habitat, in the Afrotropics and Neotropics respectively, and may therefore be considered as successful in their adaptation to this habitat, a niche that has not been exploited by any other nightjar species. However, apart from a plumage pattern that matches a rocky substrate, their known life histories provide no common factors to explain this adaptive success. The factors that they do share are common to most other nightjars. While they nest and roost on rocks, their breeding biology is remarkably different. The contrasts and lack of convergence are surprising, and suggest that these two species are not as closely related as their current congeneric status implies. This is supported by recent molecular studies that place the African and South American Caprimulgus species in different well-supported clades.     

THE ENGLISH NAMES OF THE AFROTROPICAL NIGHTJARS (CAPRIMULGIDAE)

Jackson, H. D. 1993. The English names of the Afrotropical nightjars (Caprimulgidae). Ostrich 64: 148–159.

At least 172 different English names have been used on the nightjars of Africa and its related islands, including Madagascar. A review of the literature chronicles the name changes within each species. Problems created by some duplication and transposition of names between species are discussed. A key to all the names is provided by an alphabetical list cross referenced to the species concerned. The orthography of names is discussed and it is recommended that all animal names be capitalized and freed of unnecessary hyphens. The nightjar names used in The Birds of Africa are accepted as the standard to be followed subject to a few changes.     

Africa Climate exchange

Golden Nightjar Caprimulgus eximius is an apparently sedentary sub-Saharan species with a breeding range extending from Senegal and Mauritania to Sudan. Although genetic studies of nightjars and related Caprimulgiformes have been published previously, none has included Golden Nightjar. In this study, mitochondrial and nuclear DNA of a Golden Nightjar found dead in Western Sahara in April 2016 was sequenced and compared with other species in the genus Caprimulgus. It was concluded with strong support that Golden Nightjar is closely related to Egyptian Nightjar C. aegyptius. It is hypothesised that Golden and Egyptian Nightjars may have arisen by splitting of a single ancestral species into migratory and sedentary populations.     

The food of the Afrotropical nightjars

Jackson, H.D. 2000. The food of the Afrotrapical nightjars. Ostrich 71(3&4): 408-415. A synthesis of 722 published and unpublished records of nightjar stomach contents from Afrotropical specimens was undertaken. Coleoptera were found in 84.6% of the stomachs, often in substantial numbers, beetles providing these birds with their staple diet. Lepidoptera occurred in 34.9% of the stomachs and were often present in large numbers; moths are an extremely important part of the nightjar diet in the Afrotropics, especially during winter. Orthoptera, Hemiptera and Dictyoptera, although present in 24.7, 16.3 and 11.5% of the stomachs, respectively, usually occurred in rather small numbers. Hymenoptera and lsoptera were often present in great numbers, yet were found in only 10.4 and 10.1% of the stomachs, respectively, so a limited number of individual nightjars had found emerging swarms of alate ants or termites in season. Neuroptera, Diptera, Odonata and Dermaptera were found in a few stomachs (2.4, 1.2, 0.6 and 0.3%, respectively) but these insects clearly play a very small part in the diet of nightjars in the Afrotropics. Similarities and differences in diet between some closely related nightjar species are discussed. Grit was found in 16 stomachs only, so deliberate ingestion of stones to aid digestion is regarded as extremely unlikely among nightjars in the Afrotropics. The contents of a full stomach may account for as much as 20-25% of the body mass of a nightjar.     

Diurnal body temperature patterns in free‐ranging populations of two southern African arid‐zone nightjars

Endotherms allocate large amounts of energy and water to the regulation of a precise body temperature (T_b), but can potentially reduce thermoregulatory costs by allowing T_b to deviate from normothermic levels. Many data on heterothermy at low air temperatures (T_a) exist for caprimulgids, whereas data on thermoregulation at high T_a are largely absent, despite members of this taxon frequently roosting and nesting in sites exposed to high operative temperatures. We investigated thermoregulation in free‐ranging rufous‐cheeked nightjars Caprimulgus rufigena and freckled nightjars Caprimulgus tristigma in the southern African arid zone. Individuals of both species showed labile T_b fluctuating around a single modal T_b (T_b‐mod). Average T_b‐mod was 39.7°C for rufous‐cheeked nightjars and 39.0°C for freckled nightjars. In both species, diurnal T_b increased with increasing T_a. At T_a ≥ 38°C, rufous‐cheeked nightjar mean T_b increased to 42°C, equivalent to 2.3°C above T_b‐mod. Under similar conditions, freckled nightjar T_b was on average only 1.1°C above T_b‐mod, with a mean T_b of 40.0°C. Freckled nightjars are one of the most heterothermic caprimulgids investigated to date, but our data suggest that during hot conditions this species maintains T_b within a narrow range above T_b‐mod, possibly reflecting an evolutionary tradeoff between decreased thermal sensitivity to lower T_b but increased sensitivity to high T_b. These findings reveal how general thermoregulatory patterns at similar T_a can vary even among closely related species.     

Vocal individuality of large-tailed nightjar (Caprimulgus macrurus) in Peninsular Malaysia

All four nightjar species resident in Peninsular Malaysia are vocally distinct, yet they remain little studied. Conventional field methods based on visual cues to study diurnal species may be impractical for nightjars. Alternatively, aural survey can potentially be applied on nightjars provided that individuality in their vocalisations can be proven. Our study aimed to determine the vocal individuality of the common, large-tailed nightjar (Caprimulgus macrurus) in oil palm smallholdings and an isolated forest patch located in Selangor, Peninsular Malaysia. From the call recordings obtained from 22 individuals, results of the Kruskal-Wallis analysis revealed significant differences in all the nine vocal parameters (call length, interquartile range bandwidth, low, high, average, centre and peak frequencies as well as first and third quartile frequencies) measured among individual nightjars (p < 0.001) regardless of study sites. Discriminant Function Analysis showed that more than 94.5% of original grouped cases were correctly classified. This implied that the majority of vocalizations can be assigned to individual birds based on the parameters measured. This study demonstrated the occurrence of vocal individuality in the large-tailed nightjar and such a finding pertaining to distinct vocalisations at the individual level will compensate for the limited access to visual cues in field surveys, as with the case for all nocturnal birds.     

Effects of light and prey availability on nocturnal, lunar and seasonal activity of tropical nightjars

Nightjars and their allies represent the only major group of visually hunting aerial insectivores with a crepuscular and/or nocturnal lifestyle. Our purpose was to examine how both light regime and prey abundance in the tropics, where periods of twilight are extremely short, but nightjar diversity is high, affect activity across different temporal scales. We studied two nightjar species in West African bush savannah, standard‐winged nightjars Macrodipteryx longipennis Shaw and long‐tailed nightjars Caprimulgus climacurus Vieillot. We measured biomass of potential prey available using a vehicle mounted trap and found that it was highest at dusk and significantly lower at dawn and during the night. Based on direct observations, both nightjars exhibit the most intense foraging behaviour at dusk, less intense foraging at dawn and least at night, as predicted by both prey abundance and conditions for visual prey detection. Nocturnal foraging was positively correlated with lunar light levels and ceased below about 0.03 mW m^?2. Over the course of a lunar cycle, nocturnal light availability varied markedly, while prey abundance remained constant at dusk and at night was slightly higher at full moon. Both species increased twilight foraging activity during new moon periods, compensating for the shorter nocturnal foraging window at that time. Seasonally, the pattern of nocturnal light availability was similar throughout the year, while prey availability peaked shortly after onset of the wet season and then slowly decreased over the following four months. The courtship and breeding phenology of both species was timed to coincide with the peak in aerial insect abundance, suggesting that prey availability rather than direct abiotic factors act as constraints, at least at the seasonal level. Our findings illustrate the peculiar constraints on visually orienting aerial nocturnal insectivores in general and tropical nightjars in particular and highlight the resulting nocturnal, lunar and seasonal allocation of activities.     

Woodland restoration and forest structure affect nightjar abundance in the Ozark Highlands

Chuck-will's-widow (Antrostomus carolinensis) and eastern whip-poor-will (Antrostomus vociferus) are nightjars in eastern North America that have declined 69% and 67%, respectively, in abundance since 1966, resulting in conservation concerns for these species. We investigated relationships between nightjar abundance and landscape composition, forest structure, and application of tree thinning and prescribed fire because of regional interest in woodland restoration and nightjar conservation. We conducted nocturnal nightjar surveys at 385 points in southern Missouri, USA, in 2014 and 2015 and related counts to pine (Pinus spp.) and hardwood basal area, canopy closure, percent forest cover, and percent of area thinned or burned within 500 m of survey points. We modeled abundance of chuck-will's-widow and eastern whip-poor-will using time-removal models that included a detection process and an abundance process within a hierarchical Bayesian framework. We detected 534 eastern whip-poor-will and 186 chuck-will's-widow during surveys. Our data supported global models that included all 6 vegetation and management variables for both species. Chuck-will's-widow abundance was negatively related to hardwood basal area and peaked at intermediate values of percent area burned and percent forest cover. Eastern whip-poor-will abundance was negatively related to hardwood basal area and canopy cover, positively related to percent forest cover and percent of area burned, and peaked at low to moderate levels of percent of area thinned. Relationships to forest structure and management activities generally supported the conclusion that woodland restoration benefits nightjars and that chuck-will's-widow select landscapes with less forest cover than eastern whip-poor-will.     

Environmental correlates of Freckled Nightjar ( Caprimulgus tristigma ) activity in a seasonal, subtropical habitat

We examined environmental correlates of activity in the Freckled Nightjar (Caprimulgus tristigma), a nocturnal aerial insectivore that is resident year-round in the colder and drier parts of southern Africa. Specifically, we tested the prediction that air temperature (T _a), in addition to light availability, is a significant correlate of Freckled Nightjar activity. We found that aerial insect density varied by over three orders of magnitude (from <1.0 to 117.1 insects 1,000 m⁻³) during the course of the study, and was strongly and positively related to T _a. Nightjar activity was also significantly temperature-dependent, with a cessation of activity at T _a < 12°C. Consistent with previous studies, we found that activity levels were strongly related to ambient light, with markedly reduced activity levels on dark nights. The average number of Freckled Nightjars encountered per 14.6-km transect was 1.95 ± 2.44 nightjars transect⁻¹ during nights near full moon, but only 0.17 ± 0.61 nightjars transect⁻¹ around new moon. Our study reveals that caprimulgid activity can be significantly influenced by temperature as well as ambient light.     

Model for rural transportation planning considering simulating mobility and traffic kills in the badger Meles meles

Large-scale spatial planning requires careful use and presentation of spatial data as it provides a means for communication with local stakeholders and decision makers. This is especially true for endangered species, such as the badger (Meles meles) in the Netherlands. To effectively mitigate the badger's traffic mortality in an area, two types of tools are needed. The first one estimates the probability of a successful road crossing for individual animals. The second tool is GIS-based and not only models the movement patterns of animals but also estimates an animal's daily number of road crossings. With data on population size as well as on road and traffic characteristics, a combination of both tools provides a measure of the mortality risk roads pose to wildlife in an area. Such estimations proved to be invaluable in a planning process with local inhabitants in the municipality of Brummen (the Netherlands), where ecological as well as safety problems appear. Our study demonstrates the applicability of GIS tools in balancing ecological consequences of road network options with a different distribution of traffic flows over the area in spatial planning and ecology.     

Study on the foraging behaviour of the European nightjar Caprimulgus europaeus reveals the need for a change in conservation strategy in Belgium

Effective nature conservation requires coherent actions based on the best available evidence concerning protected species. Recent studies have suggested that European nightjars Caprimulgus europaeus forage outside their recognized breeding habitats, yet, for Flanders (northern Belgium) information on nightjar foraging behaviour and key foraging habitats is lacking. To assess whether the foraging ecology of nightjars in Flanders is similar to that observed in other parts of Europe, we studied the crepuscular behaviour of this species in Bosland (northeastern Flanders) during a five‐year radio telemetry study. Tracking of 48 individuals within a coniferous forest was standardized and home ranges were calculated using a kernel density estimator (fixed kernel). Habitat use was investigated by comparing kernel placement to available habitat. Average maximal foraging distance was 2603 ± 1094 m and home ranges extended up to 691 ha. We identified the key foraging habitats to be extensively‐cultivated grasslands and recreational areas, areas that were previously assumed unsuitable for Belgian nightjars. Our results indicate the importance of foraging sites outside the breeding territory, confirming the findings of previous studies performed elsewhere in Europe. Incorporating our findings into future conservation plans could, therefore, lead to improved efficiency of EU conservation measures, designed for the protection of this bird species in Flanders.     

The Use of Automated Bioacoustic Recorders to Replace Human Wildlife Surveys: An Example Using Nightjars

To be able to monitor and protect endangered species, we need accurate information on their numbers and where they live. Survey methods using automated bioacoustic recorders offer significant promise, especially for species whose behaviour or ecology reduces their detectability during traditional surveys, such as the European nightjar. In this study we examined the utility of automated bioacoustic recorders and the associated classification software as a way to survey for wildlife, using the nightjar as an example. We compared traditional human surveys with results obtained from bioacoustic recorders. When we compared these two methods using the recordings made at the same time as the human surveys, we found that recorders were better at detecting nightjars. However, in practice fieldworkers are likely to deploy recorders for extended periods to make best use of them. Our comparison of this practical approach with human surveys revealed that recorders were significantly better at detecting nightjars than human surveyors: recorders detected nightjars during 19 of 22 survey periods, while surveyors detected nightjars on only six of these occasions. In addition, there was no correlation between the amount of vocalisation captured by the acoustic recorders and the abundance of nightjars as recorded by human surveyors. The data obtained from the recorders revealed that nightjars were most active just before dawn and just after dusk, and least active during the middle of the night. As a result, we found that recording at both dusk and dawn or only at dawn would give reasonably high levels of detection while significantly reducing recording time, preserving battery life. Our analyses suggest that automated bioacoustic recorders could increase the detection of other species, particularly those that are known to be difficult to detect using traditional survey methods. The accuracy of detection is especially important when the data are used to inform conservation.     

DNA diet profiles with high‐resolution animal tracking data reveal levels of prey selection relative to habitat choice in a crepuscular insectivorous bird

Given the global decline of many invertebrate food resources, it is fundamental to understand the dietary requirements of insectivores. We give new insights into the functional relationship between the spatial habitat use, food availability, and diet of a crepuscular aerial insectivore, the European Nightjar (Caprimulgus europaeus) by relating spatial use data with high‐throughput sequencing (HTS) combined with DNA metabarcoding. Our study supports the predictions that nightjars collect a substantial part of their daily nourishment from foraging locations, sometimes at considerable distance from nesting sites. Lepidopterans comprise 65% of nightjars'' food source. Nightjars tend to select larger species of Lepidoptera (>19 mm) which suggests that nightjars optimize the efficiency of foraging trips by selecting the most energetically favorable—larger—prey items. We anticipate that our findings may shed additional light on the interactions between invertebrate communities and higher trophic levels, which is required to understand the repercussions of changing food resources on individual‐ and population‐level processes.     

Biogeographical analysis of the flea beetle genus Chaetocnema in the Afrotropical Region: distribution patterns and areas of endemism

Aim The areal distributions of Chaetocnema species in the Afrotropical Region have been analysed with the aims of determining the distribution patterns (chorotypes) and identifying the most important areas of endemism for this flea beetle genus in sub‐Saharan Africa. Location Data were collected in sub‐Saharan Africa, including Madagascar. Methods The Afrotropical Region was divided into 103 5° quadrats (operative geographical units, or OGUs). A presence–absence matrix of the Afrotropical Chaetocnema species in the OGUs was analysed by cluster analysis (Baroni Urbani & Buser index and the WPGMA clustering method) to generate distribution pattern data based on similarity of distribution. The most important areas of endemism were identified by parsimony analysis of endemicity. Results The general distribution of Chaetocnema in the Afrotropical Region was found to be associated with moist environments and montane grasslands. Most species exhibit restricted geographical ranges. Cluster analysis revealed 120 spatial distributions that can be grouped into 13 distinct distribution patterns (chorotypes). The most important areas of endemism for Chaetocnema in sub‐Saharan Africa according to the present parsimony analysis of endemicity are: (1) central and eastern Madagascar [endemicity rate (ER) = 61.1%], (2) Western Cape Province (ER = 36.4%), (3) southern Drakensberg (ER = 26.7%), (4) the Shaba Region (ER = 16.7%), and (5) the North‐Kivu Region (ER = 5.0%). Main conclusions There are 123 known species of Chaetocnema in the Afrotropical Region, more than in any other zoogeographical region. About 91% of the species are endemic and they generally exhibit a restricted and often very localized geographical range. The remaining 9% of the species are represented by seven species that also inhabit northern Africa and/or the Arabian peninsula (C. bilunulata Demaison, C. ganganensis Bechyné, C. ljuba Bechyné, C. pulla Chapuis, C. tarsalis Wollaston, and C. wollastoni Baly), three species that widely inhabit the Palaearctic Region (C. conducta (Motschulsky), C. schlaeflini (Stierlin), and C. tibialis (Illiger)), and two species that were introduced (C. confinis Crotch, and C. picipes Stephens).     

Identifying Hot Moments in Road-Mortality Risk for Freshwater Turtles

ABSTRACT Risk assessments can be used to identify threats, which vary both in space and time, to declining species. Just as hot spots describe locations where threat processes operate at a higher rate than in surrounding areas, hot moments refer to periods when threat rates are highest. However, the identification of hot moments can be challenging because the temporal complexity of some threat processes makes their effects on population viability difficult to predict. Declining throughout much of their range, Blanding's turtle (Emydoidea blandingii) populations are potentially most vulnerable to road mortality where road densities and traffic volumes are high. The temporal variations in road-mortality risk faced by these and other semiaquatic turtles at the population level are a consequence of several factors, including sex-specific movement characteristics and seasonal changes in traffic volume. We examined these risk factors for Blanding's turtle populations in Maine, USA, by integrating temporally explicit roadkill probabilities with demographic parameters informed by local and range-wide studies. Specifically, we used population simulations to estimate the relative risk for 14 2-week periods during the turtles’ active season. Our analysis clearly identified early summer as a period of elevated risk, with June through mid-July signaling a road-mortality hot moment for Blanding's turtles (for both M and F). These findings provide guidance for the implementation of temporally explicit conservation measures such as cautionary road signage, traffic management, and public outreach that, if timed strategically, could help to mitigate population impacts from road mortality.     

ORDINAL AFFINITIES OF THE AEGIALORNITHIDAE

The Aegialornithidae of the Eocene-Oligocene, previously regarded as swifts, have been transferred by Brodkorb (1971) to the nightjar order Caprimulgiformes. The fossil forelimb bones representing this early family have now been compared with those of recent species of the true swifts and tree swifts (Apodi in Apodiformes) and with nightjars, Oilbirds and frogmouths (Caprimulgiformes). The corresponding bones in swifts differ consistently from those of nightjars in the greater development of various prominences for muscle attachment. In all critical characters the fossil bones resemble those of swifts, and it is concluded that the Aegialornithidae should be reinstated as a family of the Apodiformes.     

Human-Induced Changes in Landscape Configuration Influence Individual Movement Routines: Lessons from a Versatile,Highly Mobile Species

Landscape conversion by humans may have detrimental effects on animal populations inhabiting managed ecosystems, but human-altered areas may also provide suitable environments for tolerant species. We investigated the spatial ecology of a highly mobile nocturnal avian species–the red-necked nightjar (Caprimulgus ruficollis)–in two contrastingly managed areas in Southwestern Spain to provide management recommendations for species having multiple habitat requirements. Based on habitat use by radiotagged nightjars, we created maps of functional heterogeneity in both areas so that the movements of breeding individuals could be modeled using least-cost path analyses. In both the natural and the managed area, nightjars used remnants of native shrublands as nesting sites, while pinewood patches (either newly planted or natural mature) and roads were selected as roosting and foraging habitats, respectively. Although the fraction of functional habitat was held relatively constant (60.9% vs. 74.1% in the natural and the managed area, respectively), landscape configuration changed noticeably. As a result, least-cost routes (summed linear distances) from nest locations to the nearest roost and foraging sites were three times larger in the natural than in the managed area (mean ± SE: 1356±76 m vs. 439±32 m). It seems likely that the increased proximity of functional habitats in the managed area relative to the natural one is underlying the significantly higher abundances of nightjars observed therein, where breeders should travel shorter distances to link together essential resources, thus likely reducing their energy expenditure and mortality risks. Our results suggest that landscape configuration, but not habitat availability, is responsible for the observed differences between the natural and the managed area in the abundance and movements of breeding nightjars, although no effect on body condition was detected. Agricultural landscapes could be moderately managed to preserve small native remnants and to favor the juxtaposition of functional habitats to benefit those farm species relying on patchy resources.