Search

The nightjars of the Caprimulgus macrurus complex are distributed from Pakistan to Australia and comprise six morphologically similar but vocally distinct species. Fieldwork on Timor and Wetar, Lesser Sunda Islands, has resulted in the discovery of a seventh species in the complex, which we describe as a new species. This species has previously been confused with Caprimulgus macrurus, Caprimulgus celebensis and Caprimulgus manillensis but it differs from these and all other species in the complex by at least 13 vocal characters. Discriminant function analysis correctly classified all recordings in the complex to species. Caprimulgus ritae is known from five adult museum specimens, which are the smallest in the complex and which differ from other species in the complex in several morphological characters. A molecular phylogenetic analysis indicated that C. ritae is sister to C. meesi from Flores and Sumba, and that these species together are sister to C. macrurus. C. ritae is a tropical forest specialist occurring from sea level to at least 1500 m (probably mostly below 1000 m). Lowland and montane forests on Timor are threatened. Wetar is one of the least developed islands in Indonesia, and retains >95% natural vegetation, dominated by Eucalyptus woodlands, with tropical forests in river gorges and slopes in upland areas. Pressure for development is accelerating throughout the range of C. ritae, and a detailed assessment of its conservation status is urgently needed. [ABSTRACT FROM AUTHOR]

Although the ornithological history of southern Brazil has been amassed over the last 200 years, few attempts have been made to describe how species have accumulated. Furthermore, the collaboration of citizen scientists has considerably changed the way researchers analyze empirical data. Caprimulgidae (Nightjars and Nighthawks) species were used to illustrate how species have been recorded since the 1800s in Paraná State by comparing traditional and citizen science data. In addition, reports from both researchers and citizen scientists on the breeding biology of these caprimulgids have been verified. A literature review was conducted searching for the Caprimulgid species within the territory of Paraná. Regarding citizen science, records were obtained from four ornithological platforms. Overall, 14 species were detected within the state, 13 of which have been described in the literature, including 1 endemic to the Atlantic Forest and 3 threatened species. Citizen scientists detected all 13 taxa, in addition to one undocumented species that has never been recorded by researchers. There were 12 times more records on ornithological platforms in half of the sampling effort accumulated in studies, but most of them date from the last five years. Citizen scientists also visited 4.5 times more locations than researchers. Citizen scientists accumulated more records around September and November, and most (59%) records were from 2020–2022. Researchers mentioned species as early as 1820, while continuous studies only began during the 1980s; they concentrated their fieldwork mostly in September. Only one (2%) study sought to describe the breeding biology of a caprimulgid species, but there were 84 observations on ornithological platforms between 2004–2022 on their reproduction. Because of the evident mismatch between traditional and citizen science data due to a lack of congruence between their actions, it is suggested that ornithology in Paraná, as well as other Brazilian regions, would benefit the most if traditional and citizen scientists improved their networking communication to focus on common purposes instead of acting independently.

Simple Summary: Citizen science contributes to our scientific knowledge when non−researcher citizens collect information, usually, under the supervision of academics. It has revolutionized how traditional science is developed since it accumulates a great quantity of data over larger areas and within shorter periods of time than single researchers would be able to achieve. Both traditional and citizen science data were used to compare how caprimulgid species have been recorded in southern Brazil. Researchers mentioned 13 species from 1820–2020, and citizen scientists (from 1989–2022) detected one more species never mentioned in the literature. There have been no dialogues between traditional and citizen scientists to come together and develop an integrated approach to investigate common hypotheses. It remains unclear whether traditional and citizen scientists will realize that communicating about mutual interests can help organize and solve questions based on empirical observations. This type of joint effort could improve knowledge of caprimulgids in Paraná and other Brazilian regions. Although the ornithological history of southern Brazil has been amassed over the last 200 years, few attempts have been made to describe how species have accumulated. Furthermore, the collaboration of citizen scientists has considerably changed the way researchers analyze empirical data. Caprimulgidae (Nightjars and Nighthawks) species were used to illustrate how species have been recorded since the 1800s in Paraná State by comparing traditional and citizen science data. In addition, reports from both researchers and citizen scientists on the breeding biology of these caprimulgids have been verified. A literature review was conducted searching for the Caprimulgid species within the territory of Paraná. Regarding citizen science, records were obtained from four ornithological platforms. Overall, 14 species were detected within the state, 13 of which have been described in the literature, including 1 endemic to the Atlantic Forest and 3 threatened species. Citizen scientists detected all 13 taxa, in addition to one undocumented species that has never been recorded by researchers. There were 12 times more records on ornithological platforms in half of the sampling effort accumulated in studies, but most of them date from the last five years. Citizen scientists also visited 4.5 times more locations than researchers. Citizen scientists accumulated more records around September and November, and most (59%) records were from 2020–2022. Researchers mentioned species as early as 1820, while continuous studies only began during the 1980s; they concentrated their fieldwork mostly in September. Only one (2%) study sought to describe the breeding biology of a caprimulgid species, but there were 84 observations on ornithological platforms between 2004–2022 on their reproduction. Because of the evident mismatch between traditional and citizen science data due to a lack of congruence between their actions, it is suggested that ornithology in Paraná, as well as other Brazilian regions, would benefit the most if traditional and citizen scientists improved their networking communication to focus on common purposes instead of acting independently. [ABSTRACT FROM AUTHOR]

Copyright of Acta Zoologica Lilloana is the property of Fundacion Miguel Lillo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

En este estudio se describen los primeros datos sobre aspectos reproductivos de Nyctidromus albicollis en Bolivia mediante el monitoreo de un sitio de nidificación con fototrampeo. El periodo de monitoreo entre la incubación y el abandono del sitio de puesta por los volantones duro 30 días y se tuvo 236.89 h de registro con fototrampeo. Se observó al macho incubando en el 65.3% del tiempo, con una proporción del 75% durante el día. La hembra dedico un 34.7% a la incubación y lo hizo principalmente durante la noche. Los pichones nacieron de forma asincrónica el 28/08/2022 con diferencias entre uno y otro de 11 h, luego de 21 días uno de los volantones seguido de cerca por uno de los padres abandono el nido con el plumaje totalmente desarrollado, excepto por el largo de las plumas de la cola. El segundo pichón permaneció solo por más de 12 h y las imágenes de la trampa cámara revelan que fue depredado por una culebra verde del genero Philodryas.

Populations of avian aerial insectivores have declined across North America. A leading factor hypothesized to be driving these trends is a decline in prey populations, although a loss of suitable habitat on the landscape or other factors may also play a role. The Eastern Whip-poor-will (Antrostomus vociferus; hereafter: whip-poor-will) is an aerial insectivorous nightjar that has disappeared from many of its historic breeding locations. We investigated the role that food availability and land cover at multiple scales play in whip-poor-will distribution by estimating their abundance at 23 sites across central Illinois. To do this, we conducted nocturnal point counts to estimate whip-poor-will abundance and collected nocturnal insects using UV-light traps at these sites to quantify potential food abundance. Additionally, we described whip-poor-will diet using DNA metabarcoding of fecal samples. We found that the number of large moths at a site had a positive effect on the abundance of whip-poor-wills, aligning with our diet analysis which identified moths as the primary prey item for this species (present in 92% of samples). Whip-poor-wills also showed an affinity for forest edges, but only when edges were associated with high moth abundances. Conversely, developed land-cover in landscapes surrounding sites led to decreased whip-poor-will abundance. Given the continued expansion of developed areas, coupled with concerning trends in moth populations, declines in the abundance of this species may continue. Efforts should be made to protect and sustain moth populations and the impacts of development should be scrutinized in the pursuit of conserving whip-poor-wills. [ABSTRACT FROM AUTHOR]

Copyright of Ornitologia Colombiana is the property of Asociacion Colombiana de Ornitologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background The Savanna Nightjar (Caprimulgus affinis) is a widespread, polytypic species which was previously treated as two or three species. It is currently treated as a single species based on superficial similarity of their songs but no detailed comparisons of the songs in this complex have been made. Methods A total of 15 acoustic variables were measured for the songs of 86 individuals representing 8 of the 10 subspecies in the complex. Results Three major groups can be distinguished based on univariate and multivariate analyses: a northern group consisting of the subspecies C. a. monticolus, C. a. amoyensis and C. a. stictomus; a southern group consisting of C. a. affinis, C. a. kasuidori, C. a. timorensis and C. a. propinquus; and a third group in the Philippines consisting of C. a. griseatus. Conclusions It is here argued that these groups are best treated as species, and that Franklin’s Nightjar (C. monticolus) and Kayumanggi Nightjar (C. griseatus) are reinstated as separate species.

Background: The Savanna Nightjar (Caprimulgus affinis) is a widespread, polytypic species which was previously treated as two or three species. It is currently treated as a single species based on superficial similarity of their songs but no detailed comparisons of the songs in this complex have been made. Methods: A total of 15 acoustic variables were measured for the songs of 86 individuals representing 8 of the 10 subspecies in the complex. Results: Three major groups can be distinguished based on univariate and multivariate analyses: a northern group consisting of the subspecies C. a. monticolus, C. a. amoyensis and C. a. stictomus; a southern group consisting of C. a. affinis, C. a. kasuidori, C. a. timorensis and C. a. propinquus; and a third group in the Philippines consisting of C. a. griseatus. Conclusions: It is here argued that these groups are best treated as species, and that Franklin's Nightjar (C. monticolus) and Kayumanggi Nightjar (C. griseatus) are reinstated as separate species. [ABSTRACT FROM AUTHOR]

The Pennant-winged Nightjar Caprimulgus vexillarius was described in 1838 by John Gould from a male in breeding plumage, but its given locality, various islands in the Indian Ocean and Red Sea coasts, was eventually deemed unreliable and replaced in the early 20th century with 'Sierra Leone', until the latter too was noticed to be far outside the species' usual range. Most recently, the type locality has been suggested to be 'southern Africa'. Using his extensive published correspondence, and other information, I discuss Gould's contacts and preparation for a monograph of the Caprimulgidae during the mid-1830s. Clues as to where he may have acquired such a specimen are virtually non-existent, and there is no definite evidence to suggest that Gould received it from any of the terra typica mentioned. Nevertheless, the possibility that this species could wander to islands in the Indian Ocean, and elsewhere far outside the usual range, is clearly evidenced by modern sightings and historical specimens. [ABSTRACT FROM AUTHOR]

Grit ingestion is widespread among birds, as an aid for grinding up food and as a dietary supplement of calcium, but is less common among insectivores, especially aerial feeders like nightjars (Caprimulgidae). I report recurrent visits by Common Nighthawks (Chordeiles minor) to a gravel driveway in British Columbia at dusk over a 4-y period. These ground visits were highly consistent (nighthawks landed during 93% of 72 dusk watches) and visits were highly concentrated both in time (95% of time on the ground between 10 and 57 min after sunset) and space (91% of the birds' time was spent in 2 areas comprising only 31% of the visible study site). Birds pecked at the ground in 97% of 198 focal-animal watches. In 43 visits the nighthawks picked up or swallowed some item; in 24 cases this was a small piece of gravel and no other items were identified. Surveys of ground arthropods in the study area over 3 y showed that potential prey were sparse (mean <2 insects m–2) and the most common insects were unsuitable prey (tiny 3-mm ants). I conclude that the only reason for the nighthawks to consistently visit this gravel area was to ingest grit. The gravel ingested was crushed limestone, which might support a calcium uptake hypothesis. Grit ingestion, occurring within a restricted dusk period, might not explain why nightjars often sit on gravel roads at night, which is a major source of mortality for several species. Information on ground behavior in Caprimulgidae is important for understanding their mortality risks and conservation. [ABSTRACT FROM AUTHOR]

Copyright of Zeledonia is the property of Asociacion Ornitologica de Costa Rica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Little is known of the natural history of the Solomons Nightjar (Eurostopodus nigripennis) due to its restricted range and reclusive nature. Here we describe the breeding biology of E. nigripennis based on nests found in the Western Province, Solomon Islands, between June and October 2019. Four nests were discovered on 3 small islands: Tetepare, Hehevai, and Nanakatopa; the latter 2 are first island records for this species. We observed all stages of the species' nesting cycle, from egg to post-fledging care of juveniles by adults, each with a single nestling (n = 4). We describe the eggs, nestlings, and juvenile plumage of the species with additional detail on nesting habitat and document new breeding locations in the Western Province. [ABSTRACT FROM AUTHOR]

Many nocturnal animals, including invertebrates such as scorpions and a variety of vertebrate species, including toadlets, flying squirrels, owls, and nightjars, emit bright fluorescence under ultraviolet light. However, the ecological significance of this unique coloration so attached to nocturnality remains obscure. Here, we used an intensively studied population of migratory red-necked nightjars (Caprimulgus ruficollis) to investigate inter-individual variation in porphyrin-based pink fluorescence according to sex, age, body condition, time of the year, and the extent of white plumage patches known to be involved in sexual communication. Males and females exhibited a similar extent of pink fluorescence on the under-side of the wings in both juvenile and adult birds, but males had larger white patches than females. Body condition predicted the extent of pink fluorescence in juvenile birds, but not in adults. On average, the extent of pink fluorescence in juveniles increased by ca. 20% for every 10-g increase in body mass. For both age classes, there was a slight seasonal increase (1–4% per week) in the amount of fluorescence. Our results suggest that the porphyrin-based coloration of nightjars might signal individual quality, at least in their first potential breeding season, although the ability of these and other nocturnal birds to perceive fluorescence remains to be unequivocally proven. [ABSTRACT FROM AUTHOR]

Keywords: Andes; Caprimulgidae; Colonso-Chalupas Biological Reserve; pasture EN Andes Caprimulgidae Colonso-Chalupas Biological Reserve pasture 203 205 3 01/18/21 20201201 NES 201201 We describe the first breeding record of a Blackish nightjar ( I Nyctipolus nigrescens i ) in a pasture habitat dominated by tropical grasses (Figure 1(a-d)) located at the buffer zone of the Colonso-Chalupas Biological Reserve, in the Napo province in eastern Ecuador. Since caprimulgids are mostly nocturnal and have cryptic behaviour, not a great deal of literature is available on their breeding strategies [[6]]. So far, breeding records have been documented in Ecuador [[8]], Brazil [[10]], Surinam [[11]], the Guianas [[13]] with also the documented double brood in French Guiana [[15]] and aberrant coloured juveniles in Ecuador [[9]]. 9 Solano-Ugalde A, Vits C, Ingels J. Notes on the breeding of the Blackish Nightjar (Caprimulgus nigrescens) in south-eastern Ecuador, including the first record of aberrantly coloured juveniles NOTAS. [Extracted from the article]

Abstract: Phenology match–mismatch usually refers to the extent of an organism's ability to match reproduction with peaks in food availability, but when mismatch occurs, it may indicate a response to another selective pressure. We assess the value of matching reproductive timing to multiple selective pressures for a migratory lunarphilic aerial insectivore bird, the whip‐poor‐will (Antrostomus vociferus). We hypothesize that a whip‐poor‐will's response to shifts in local phenology may be constrained by long annual migrations and a foraging mode that is dependent on both benign weather and the availability of moonlight. To test this, we monitored daily nest survival and overall reproductive success relative to food availability and moon phase in the northern part of whip‐poor‐will's breeding range. We found that moth abundance, and potentially temperature and moonlight, may all have a positive influence on daily chick survival rates and that the lowest chick survival rates for the period between hatching and fledging occurred when hatch was mismatched with both moths and moonlight. However, rather than breeding too late for peak moth abundance, the average first brood hatch date actually preceded the peak moth abundance and occurred during a period with slightly higher available moonlight than the period of peak food abundance. As a result, a low individual survival rate was partially compensated for by initiating more nesting attempts. This suggests that nightjars were able to adjust their breeding phenology in such a way that the costs of mismatch with food supply were at least partially balanced by a longer breeding season. [ABSTRACT FROM AUTHOR]

The status o f the Egyptian Nightjar Caprimulgus aegyptius in the Arabian Peninsula, and in particular in the United Arab Emirates, has changed in recent years. A newly discovered breeding population in the UAE was studied from 2014 to 2017. Singing males and fledged juveniles were recorded each year, and nests with eggs were discovered in March 2016 and April 2017. The habitat utilised by nesting and communally roosting birds, details o f adult behaviour (including an apparent display flight during courtship and distraction display at the nest), aspects o f breeding ecology, juvenile behaviour and the moult phenology at the study site are described. [ABSTRACT FROM AUTHOR]

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 NightjarCaprimulgus 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. [ABSTRACT FROM PUBLISHER]

Golden NightjarCaprimulgus eximiusis 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 genusCaprimulgus. It was concluded with strong support that Golden Nightjar is closely related to Egyptian NightjarC. aegyptius. It is hypothesised that Golden and Egyptian Nightjars may have arisen by splitting of a single ancestral species into migratory and sedentary populations. [ABSTRACT FROM AUTHOR]

Birds in the order Caprimulgiformes (nightjars and allies) have a remarkable capacity for thermoregulation over a wide range of environmental temperatures, exhibiting pronounced heterothermy in cool conditions and extreme heat tolerance at high environmental temperatures. We measured thermoregulatory responses to acute heat stress in three species of Caprimulgiformes that nest in areas of extreme heat and aridity, the common poorwill (Phalaenoptilus nuttallii: Caprimulgidae) and lesser nighthawk (Chordeiles acutipennis: Caprimulgidae) in the Sonoran Desert of Arizona, and the Australian owlet-nightjar (Aegotheles cristatus: Aegothelidae) in the mallee woodlands of South Australia. We exposed wild-caught birds to progressively increasing air temperatures (Ta) and measured resting metabolic rate (RMR), evaporative water loss (EWL), body temperature (Tb) and heat tolerance limit (HTL; the maximum Ta reached). Comparatively low RMR values were observed in all species (0.35, 0.36 and 0.40 W for the poorwill, nighthawk and owletnightjar, respectively), with Tb approximating Ta at 40°C and mild hyperthermia occurring as Ta reached the HTL. Nighthawks and poorwills reached HTLs of 60 and 62°C, respectively, whereas the owlet-nightjar had a HTL of 52°RMRC. RMR increased gradually above minima at Ta of 42, 42 and 35°C, and reached 1.7, 1.9 and 2.0 times minimum resting values at HTLs in the poorwill, nighthawk and owletnightjar, respectively. EWL increased rapidly and linearly as Ta exceeded Tb and resulted in maximum rates of evaporative heat dissipation equivalent to 237-424% of metabolic heat production. Bouts of gular flutter resulted in large transient increases in evaporative heat loss (50-123%) accompanied by only small increments in RMR (<5%). The cavity-nesting/roosting owletnightjar had a lower HTL and less efficient evaporative cooling compared with the species that nest and/or roost on open desert surfaces. The high efficiency of gular flutter for evaporative cooling, combined with mild hyperthermia, provides the physiological basis for defending Tb well below Ta in extreme heat and is comparable to the efficient cooling observed in arid-zone columbids in which cutaneous EWL is the predominant cooling pathway. [ABSTRACT FROM AUTHOR]

Endotherms allocate large amounts of energy and water to the regulation of a precise body temperature (Tb), but can potentially reduce thermoregulatory costs by allowing Tb to deviate from normothermic levels. Many data on heterothermy at low air temperatures (Ta) exist for caprimulgids, whereas data on thermoregulation at high Ta 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 Tb fluctuating around a single modal Tb (Tb-mod). Average Tb-mod was 39.7°C for rufous-cheeked nightjars and 39.0°C for freckled nightjars. In both species, diurnal Tb increased with increasing Ta. At Ta ≥ 38°C, rufous-cheeked nightjar mean Tb increased to 42°C, equivalent to 2.3°C above Tb-mod. Under similar conditions, freckled nightjar Tb was on average only 1.1°C above Tb-mod, with a mean Tb 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 Tb within a narrow range above Tb-mod, possibly reflecting an evolutionary tradeoff between decreased thermal sensitivity to lower Tb but increased sensitivity to high Tb. These findings reveal how general thermoregulatory patterns at similar Ta can vary even among closely related species. [ABSTRACT FROM AUTHOR]

The known status of Egyptian Nightjar in the United Arab Emirates has changed in recent years. Formerly considered a highly localised winter visitor and scarce passage migrant, a fledged juvenile found in June 2013 raised the possibility of local breeding at Ajban, Abu Dhabi emirate. Subsequent fieldwork 2014-2017 at that location indicated the presence of a small population, with singing males and fledged juveniles recorded annually and nests found in 2016 and 2017. This short paper reviews the prior status of the species in the UAE and outlines results concerning evidence for breeding from an ongoing study. [ABSTRACT FROM AUTHOR]

Little is known about the wintering distribution of the European Nightjar Caprimulgus europaeus. We combined geolocator and GPS-logger data from different sites in Western Europe to analyse migration routes and migration timing of this trans-equatorial migrant. Nightjars followed a loop migration route during which they cross two ecological barriers, and converged near common stopover zones in Northern, Central and Western Africa, where they stayed for 2-3 weeks. Nightjars used the same stopover sites as several other European migrants, relying on small and discrete wintering areas within the Democratic Republic of Congo. This confirms the importance of these specific zones and highlights the vulnerability of Western European populations to habitat loss in their non-breeding areas. [ABSTRACT FROM AUTHOR]

Obligate insectivorous birds breeding in high latitudes travel thousands of kilometres during annual movements to track the local seasonal peaks of food abundance in a continuously fluctuating resource landscape. Avian migrants use an array of strategies when conducting these movements depending on e.g. morphology, life history traits and environmental factors encountered en route. Here we used geolocators to derive data on the annual space-use, temporal pattern and migratory strategies in an Afro-Palaearctic aerial insectivorous bird species - the European nightjar Caprimulgus europaeus. More specifically, we aimed to test a set of hypothesises pertaining to the migration of a population of nightjars breeding in south-eastern Sweden. We found that the birds wintered across the central and western parts of the southern tropical Africa almost entirely outside the currently described wintering range of the species. The nightjars performed a narrow loop migration across Sahara, with spring Sahel stopovers significantly to the west of autumn stops indicative to an adaptive response to winds during migration. To our surprise, the migration speed was faster in the autumn (119 km d− 1) than in the spring (99 km d− 1), possibly due to the prevailing wind regimes over the Sahara. The estimated flight fraction in both autumn (14%) and spring (12%) was almost exactly as the theoretically predicted 1:7 time relationship between flights and stopovers for small birds. The temporal patterns within the annual cycle indicate that individuals follow alternative spatiotemporal schedules that converge towards the breeding season. The positive relationship between the spatially and temporally distant winter departure and breeding arrival suggests that individuals´ temporal fine-tuning to breeding may be constrained, leading to potential negative fitness consequences. [ABSTRACT FROM AUTHOR]

If the fitness effects of amino acid mutations are conditional on genetic background, then mutations can have different effects depending on the sequential order in which they occur during evolutionary transitions in protein function. A key question concerns the fraction of possible mutational pathways connecting alternative functional states that involve transient reductions in fitness. Here we examine the functional effects of multiple amino acid substitutions that contributed to an evolutionary transition in the oxygenation properties of avian hemoglobin (Hb). The set of causative changes included mutations at intradimer interfaces of the Hb tetramer. Replacements at such sites may be especially likely to have epistatic effects on Hb function since residues at intersubunit interfaces are enmeshed in networks of salt bridges and hydrogen bonds between like and unlike subunits; mutational reconfigurations of these atomic contacts can affect allosteric transitions in quaternary structure and the propensity for tetramer--dimer dissociation. We used ancestral protein resurrection in conjunction with a combinatorial protein engineering approach to synthesize genotypes representing the complete set of mutational intermediates in all possible forward pathways that connect functionally distinct ancestral and descendent genotypes. The experiments revealed that 1/2 of all possible forward pathways included mutational intermediates with aberrant functional properties because particular combinations of mutations promoted tetramer--dimer dissociation. The subset of mutational pathways with unstable intermediates may be selectively inaccessible, representing evolutionary roads not taken. The experimental results also demonstrate how epistasis for particular functional properties of proteins may be mediated indirectly by mutational effects on quaternary structural stability. [ABSTRACT FROM AUTHOR]

Nightjars represent a model taxon for investigating physiological limits of heat tolerance because of their habit of roosting and nesting in sunlit sites during the heat of the day. We investigated the physiological responses of Rufous-cheeked nightjars ( Caprimulgus rufigena) and Freckled nightjars ( Caprimulgus tristigma) to high air temperatures ( T ) by measuring body temperature ( T ), resting metabolic rate (RMR) and total evaporative water loss (TEWL) at T ranging from 10 to 56 °C. Both species became hyperthermic at T > T . Lower critical limits of thermoneutrality occurred at T between 35 and 37 °C, whereas we detected no clear upper critical limits of thermoneutrality. Between T ≈ 37.0 and 39.9 °C, rates of TEWL increased rapidly with T . At T ≥ 40 °C, fractional increases in mass-specific TEWL rates were 78-106% of allometric predictions. Increasing evaporative heat dissipation incurred only small metabolic costs, with the RMR of neither species ever increasing by more than 20% above thermoneutral values. Consequently, both species displayed extremely efficient evaporative cooling; maximum evaporative heat dissipation was equivalent to 515% of metabolic heat production (MHP) at T ≈ 56 °C in C. rufigena and 452% of MHP at T ≈ 52 °C in C. tristigma. Our data reiterate that caprimulgids have evolved an efficient mechanism of evaporative cooling via gular fluttering, which minimizes metabolic heat production at high T and reduces total heat loads. This likely aids in reducing TEWL rates and helps nightjars cope with some of the most thermally challenging conditions experienced by any bird. [ABSTRACT FROM AUTHOR]

Nest predation is a major threat to the survival of young birds and is thus a crucial selective pressure influencing the evolution of life history traits. Injury feigning is a nest-defense mechanism in which the parents attract the attention of predators to secure their offspring. Because parents may incur a cost from injury feigning, they should adjust their injury-feigning behavior to different situations to maximize fitness. In this study, we used the Savanna Nightjar, Caprimulgus affinis, as a model organism to test the vulnerability and brood value hypotheses for predicting the occurrence of injury-feigning behavior. A field study was performed between 2006 and 2012, and observations were recorded from 123 nests. Both nestling movement and injury feigning increased after hatching, reached their peak at a nestling age of 8-10 days, and then declined afterward. In addition, the frequency of injury feigning by the female differed between habitats, being higher in a low-plant-cover habitat than in a high-plant-cover habitat. Both findings are consistent with the vulnerability hypothesis. By contrast, the intensity of injury-feigning behavior did not linearly increase with nestling age and brood size; thus, the brood value hypothesis was not supported. [ABSTRACT FROM AUTHOR]

Fires are an ecological process essential for species dependent on early successional habitat in forested landscapes. In a wildlife context, clearcut forestry practices can mimic forest fires through the creation of early successional forest clearings, however, evidence that clearcuts provide the same ecological value as fire is mixed. In temperate deciduous/hardwood forests, many species that depend on early successional habitat are known to use clearcuts, including Eastern Whip-poor-wills ( Antrostomus vociferous ) and Common Nighthawks ( Chordeiles minor ), two threatened aerial insectivorous birds. However, the relative importance of recent clearcuts as breeding habitat relative to other more naturally open habitat types in the boreal forest is unknown. In May-July 2015 we studied occupancy and detectability of these two species in the boreal forest of northwestern Ontario. We first determined whether occupancy differed among three open habitats: burned stands, recent clearcuts, and open wetlands, and whether it differed in relation to the size of clearcut patches. We also examined how detectability of each species varied with time of day, season and weather conditions. Site occupancy for the Eastern Whip-poor-will and Common Nighthawk averaged 0.413 and 0.437, respectively. We found no significant difference in occupancy of either species in relation to burned stands, recent clearcuts, or open wetlands, although Eastern Whip-poor-will occupancy tended to be higher in burned stands. Occupancy did not show a linear relationship with patch size but neither species was found in the smallest open patches (<3 ha), perhaps indicating a minimum size threshold, although further study is needed. The detection of each species was positively correlated with the occurrence of the other species, suggesting that they were both selecting similar site characteristics. Detectability for Eastern Whip-poor-will was highest after sunset and increased over the course of the breeding season, while for Common Nighthawk, detectability was similar during and after sunset and decreased over the season. Our results suggest that Eastern Whip-poor-will and Common Nighthawk show similar preference for natural and managed open sites and that recent clearcuts may provide early successional habitat in the absence of burned stands. Our results also extend the known breeding range of Eastern Whip-poor-will, which further emphasizes the need for future research on these poorly studied species in the boreal forest. [ABSTRACT FROM AUTHOR]