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A territory mapping method has been employed in 2015 to assess the population density of 8 non-passerine and 10 passerine uncommon bird species breeding in a peri-urban riparian forest (280 ha) along Zambezi River (7 km long) near Katima Mulilo NE Namibia. The population densities (pairs per 100 ha) are estimated as follows: Trumpeter Hornbill: 1.4, Schalow’s Turaco: 2.9, Green-backer Heron: 1.1, Little Bittern: 0.4, Lesser Jacana: 0.4, African Finfoot: 0.4, White-crowned Lapwing: 0.7, Long-billed Crombec: 3.9, Yellow White-eye: 4.3, Scarlet-chested Sunbird: 0.7, African Golden Oriole: 2.9, Black-headed Oriole: 0.7, Violet-backed Starling: 0.7, Pied Wagtail: 8.6, Ashy Flycatcher: 0.4, Black Flycatcher: 0.4, Hartlaub’s Babbler: 4.3.

Africa’s montane ecosystems are noteworthy not only for their isolation but for their morphologically similar bird populations that inhabit geographically disparate localities. Many species possess range disjunctions in excess of 2,000 km and appear to represent populations that have been isolated since at least the last Ice Age, including the Northern Double-collared Sunbird (Cinnyris reichenowi). Recent work on other Afromontane birds has demonstrated substantial phylogeographic structure can exist in phenotypically similar populations, with cryptic species occurring parapatrically within the same mountain range. We explored genetic, morphological, and ecological diversity within C. reichenowi to assess whether cryptic regional diversification occurs across the disjunct portions of this species’ range. Within C. reichenowi, we find consistent patterns of morphological disparity that coincide with genetic diversification between xeric and wet montane populations within the Cameroon Line in the Western population, and clear genetic differentiation between Western and Eastern populations. Our research demonstrates that the geographically isolated populations of C. reichenowi represent different species, and that ecological diversification is shaping populations within Central Africa. We show here that two named populations should be recognized as members of a western species in the Northern Double-collared Sunbird complex: nominate Cinnyris preussi preussi in the Cameroon Line montane forests, and Cinnyris preussi genderuensis in the more xeric interior of Cameroon and the Central African Republic, likely occurring in adjacent Nigeria as well.

Nest predation is the dominant cause of nest failure in the tropics. However, our knowledge about tropical nest predator identity and community structure is still quite limited. On 9 January 2019, we video-recorded an Olive Sunbird (Cyanomitra olivacea) removing and flying off with an egg from an African Paradise Flycatcher (Terpsiphone viridis) nest in the East Usambara Mountains, Tanzania. This observation is surprising because the Olive Sunbird is a specialized nectarivore. Nectar, however, is a poor source of nitrogen and cannot meet the protein requirements for nectarivores. We hypothesize that bird eggs are a potential source of protein for selected long-billed sunbird species—species that can grasp and handle small bird eggs. Our observation of nest predation by an Olive Sunbird adds a heretofore unknown behavior to nectarivores in general and to sunbirds specifically.

Birds provide multiple ecological services that benefit humans including pollination. In Africa, sunbirds are the dominant vertebrate pollinator. Here we present a species-level assessment for African sunbirds of the number and relative frequency of their food plants that have useful properties to humans. We conducted this analysis by compiling and integrating known sunbird food plants with useful tropical plant and tropical cultivated plant databases. Across Africa, 68% of the 329 genera and 44% of the 468 species of sunbirds’ known food plants are used by humans for medicine, food, building materials, or other uses. Yet most genera and species of useful plants are visited by a small number of sunbird species. The median number of sunbird species that visit a useful genus and species of plant is two and one, respectively. Of the 409 genera and 308 species of useful plants that are sunbird pollinated across one or more of the six predominant habitats for sunbirds, 67% of genera and 71% of species are pollinated by sunbird species that are forest or woodland dependent. Additionally, 58% of all genera and 83% of all species of useful plants pollinated by sunbirds are non-cultivated. In Africa, non-cultivated sunbird-pollinated useful plants are almost entirely collected, used, and traded locally rather than regionally or internationally. Our results indicate that African sunbirds provide important ecological services as pollinators that benefit humans, and these services are provided largely at a local scale. Given the decline of invertebrate and vertebrate pollinators both globally and in Africa, sunbirds are important to the long-term conservation of many useful plants in Africa and hence human well-being.

A new quill mite species, Neoaulonastus sidorchukae sp. nov. (Acariformes: Syringophilidae), is described from under-tail covert feathers of Leptocoma zeylonica (Linnaeus) (Passeriformes: Nectariniidae) from Sri Lanka. It is the second record of syringophilid mites of the genus Neoaulonastus parasitizing sunbirds.

Many plant species contain plant secondary metabolites (PSMs), such as alkaloids, in their tissues for protection against herbivore attack, but PSMs can also be found in floral nectar. Some pollinators have been shown to discriminate against floral nectar with PSMs and consuming PSMs may have negative fitness effects on pollinators. However, only a few studies have investigated the effects of ecologically relevant levels of PSMs on pollinator foraging performance. Here, we addressed the question of whether the natural concentrations of the alkaloids, nicotine and anabasine, found in tree tobacco, Nicotiana glauca, nectar affect foraging performance in Palestine sunbird, Nectarinia osea, pollinators that use the plant's nectar as a food source. We trained foraging sunbirds to discriminate between rewarding and nonrewarding artificial flowers based on colour. We measured sunbird foraging performance through their accuracy at distinguishing the two colours immediately after training (pretreatment), and again the following day after consuming sucrose solutions with or without alkaloids (post-treatment). We also explored other potential effects of PSM consumption by assessing bird activity level and flower visit rate. Birds that consumed alkaloids did not significantly change their activity level or flower visit rate across time (pre- and post-treatment) compared to birds that did not consume alkaloids (no significant time by treatment interaction). However, alkaloid consumption significantly decreased sunbird foraging performance in terms of their accuracy in distinguishing the rewarding colour, potentially due to reduced memory retention and/or other cognitive or physiological impairments following alkaloid consumption. We also found that sunbirds discriminated against higher, in favour of lower, ecologically relevant alkaloid concentrations in the nectar of tree tobacco and that previous exposure to alkaloids reduced overall consumption of alkaloid solutions. Reduced foraging performance due to PSM ingestion could greatly affect a pollinator's foraging efficiency, which could, in turn, affect both pollinator and plant reproductive fitness.

We describe the nest of the endemic Whitehead's Spiderhunter (Arachnothera juliae) from Mt. Mulu National Park, Sarawak, Malaysian Borneo, and compare it to those of the most closely related species, the Yellow-eared Spiderhunter (A. chrysogenys) and the Naked-faced Spiderhunter (A. clarae). The nest was found on 3 August 2014 in lower montane forest at 1,400 m elevation along the summit trail on the western slopes of Mt. Mulu. It consisted of a bowl lined with fine bark material inside a naturally occurring hanging ball of moss 19 m above the ground in a large tree. It contained no eggs, but the pair was observed carrying in nest materials on several occasions.

The abundance of consumers and the availability of resources are often linked, and birds are known to track food resources at a variety of spatial and temporal scales. This study describes the seasonal influx of nectar-feeding birds during flowering in a 51-ha stand of Aloe ferox in the Eastern Cape, South Africa, over 5 years (2008–09 and 2011–13). Bimonthly point counts of birds were conducted before (April–May), during (June–July) and after (August) flowering, which occurs during the austral winter. The abundance of nectar-feeding birds increased significantly during flowering each year, whereas monthly abundances of non-nectarivores were unrelated to flowering. Models fitted to bird count-data revealed a significant interaction between feeding guild (nectarivorous versus non-nectarivorous species) and the percentage of flowering A. ferox over the 5 years of the study, confirming that these guilds responded differently to flowering events. Malachite Sunbirds (Nectarina famosa), which are specialist nectarivores, responded consistently to flowering of A. ferox each year, despite the low sugar concentrations of A. ferox nectar. The arrival of nectar-feeding birds en masse during flowering, and the number of bird species (16) observed feeding on A. ferox nectar, suggest that this plant is an important source of nutrition for birds at a time when other food resources are likely to be scarce.

Floral color is an important cue that converged in many ornithophilous flowers and can be used by nectarivorous birds to make foraging decisions. Wild ornithophilous flowers are frequently red, although they are more often yellow in Israel. The Palestine sunbird (Nectarinia osea) is the only nectarivorous bird in Israel and surrounding Mediterranean areas. Given the prevalence of yellow flowers in their habitats (along with sunbirds' expected sensitivity increase in this region of color vision), we predicted that Palestine sunbirds prefer yellow food sources over red. We examined sunbird foraging behavior when they were presented simultaneously with a yellow and red feeder, each containing the same quantity and quality of food. We investigated whether sunbirds had a side bias in the color preference experiment, but also in a separate experiment where both feeders were white. Sunbirds did not exhibit a significant color bias, while they did have a significant preference for a particular side of the cage. Location appears to be a more important cue than color to Palestine sunbirds, likely because location can offer information on the most rewarding plants and recently depleted flowers. However, color may still provide useful information that could influence foraging decisions in different contexts.

Several sunbird species (Nectariniidae) exhibit group display, but the function of this behaviour still remains unclear. We test two hypotheses (reproductive tactic and joint territory defence) to explain the function of this behaviour using data gathered on Northern Double-collared Sunbirds (Cinnyris reichenowi) from the Cameroon Mountains. Sunbirds exhibited group display throughout the breeding cycle. Groups of birds were mainly comprised of neighbouring pairs aggregated at territory boundaries. The frequency of group displays varied significantly among individuals and over the breeding cycle, with the highest frequency during the pre-breeding period and the lowest during egg-laying (∼female's fertile period). Time spent on group display was significantly longer at the end of breeding. Off-territory forays were recorded for both males and females, males significantly increased the time spent on these forays during incubation. Extra-pair copulations were recorded only in five cases for females (4%) suggesting that most off-territory forays were motivated by feeding on nectar in neighbouring territories. Therefore, we suggest that the behaviour is used for joint territory defence rather than as an information centre for choosing mates for extra-pair copulations. Its function for choosing primary mates is also unlikely, because group displays were mainly observed in complete pairs.

Observations on nesting Beautiful Long-tailed Sunbirds Cinnyris pulchellus in The Gambia revealed that some females have dark or partially dark bibs, contrary to most accounts in the literature. Furthermore, all fledglings seen in The Gambia also had dark bibs and some males in eclipse plumage or lacking tail-streamers engaged in breeding activity. The conclusion that some adult female C. pulchellus have dark bibs and that some, probably all, juveniles have dark bibs was confirmed from museum specimens. It is further demonstrated, based on specimens, that some adult females and juveniles of Gorgeous Sunbird C. melanogastrus also have dark bibs.

Many aspects of the breeding biology of Afrotropical forest birds are poorly known. Here we provide a description based on the monitoring of 1461 active nests over eight breeding seasons about one or more aspects of the breeding biology for 28 coexisting understory bird species on the Amani Plateau in the East Usambara Mountains, Tanzania. Mean nest height and mean distance of nest from forest edge varied widely among species with most species constructing nests across a broad vertical and forest edge to interior gradient. However, there were important exceptions with all sunbird species and several dove and waxbill species constructing nests in close proximity to the forest edge. For 17 common species for which we recorded two or more active nests, mean clutch size across species was 1.9 eggs per clutch, the lowest site-specific mean clutch size yet reported for a tropical forest bird community. For nine bird species, a subset of the 17 common species, length of breeding season, defined as the d...

At least four hypotheses have been suggested to explain the formation and maintenance of song dialects among birds: historic processes (epiphenomenon), genetic or local adaptation, acoustic adaptation, and social adaptation. We studied spatial and temporal distribution of dialect in the orange-tufted sunbird (Nectarinia osea), a small nectarivorous bird that expanded its breeding range in Israel during the past 100 years from the southern part of Rift Valley to the entire country. Sunbird range expansion was concurrent with the establishment of many small settlements with an ethos of gardening, which introduced many ornithophilous plants. We recorded songs and genetically screened individual sunbirds in 29 settlements distributed across a 380 km north–south gradient along the Rift Valley. We show that dialects cluster together into geographical regions in 70% of cases, a moderate concurrence to geography. Settlement establishment date, geographical position, and genetic distance between local populations (i.e., settlements) were all poor predictors for the variance among song dialects. The specific effect of habitat was not tested because all sampled localities were similar in their physical and acoustic properties. Using a network analysis, we show that dialects seem to aggregate into several network communities, which clustered settlement populations from several regions. Our results are best explained by either the epiphenomenon hypothesis or the social adaptation hypothesis, but at present our data cannot state unequivocally which of these hypotheses is better supported. Last, we discovered a negative association between network centrality and genetic diversity, a pattern that requires further examination in other systems.

The winter-flowering succulent Aloe marlothii provides nectar for many opportunistic avian nectarivores in southern African savannas. We assessed the importance of A. marlothii nectar sugar for opportunistic nectarivores by analysing temporal changes in stable carbon isotope ratios (δ 13 C) in the tissues of birds in Suikerbosrand Nature Reserve, South Africa. The blood of the 11 most common non-granivorous opportunistic nectarivores at our site was enriched in 13 C by 3.4 ± 1.5‰, during the flowering period of A. marlothii, reflecting the enriched crassulacean acid metabolism (CAM) isotopic signature of nectar (-12.6 ± 0.5‰). This relatively small contribution of A. marlothii nectar to assimilated carbon in whole blood contrasted with that of exhaled CO 2 in African Red-eyed Bulbuls Pycnonotus nigricans and Cape White-eyes Zosterops capensis. In both these species, the δ 13 C of breath samples was significantly enriched compared with blood and feathers, and closely resembled that of the nectar, revealing combustion of ingested nectar rather than assimilation. Although our analysis was complicated by the presence of C 4 grasses, whose δ 13 C values are similar to those of CAM photosynthesizers, when considered with previously published feeding observations our data reveal that opportunistic nectarivores feeding on A. marlothii nectar obtain a relatively small fraction of their assimilated carbon, but most of their metabolized carbon, from this seasonally available carbohydrate food resource. Because the δ 13 C values of insects associated with C 3 plants also became enriched during the flowering season, some insect-eating opportunistic nectarivores may have assimilated A. marlothii carbon indirectly from insects. This study highlights the importance of understanding isotopic routing when assessing the nutritional significance of specific dietary items to consumer communities.

Diurnal birds generally sleep during the hours of darkness. Most male southern African sunbirds have pectoral tufts, although the function of these is not always understood. We examined nocturnal tuft display in male malachite sunbirds (Nectarinia famosa) and found that they display their pectoral tufts almost continuously throughout the night, whilst asleep.We suggest the possible function of this behaviour and suggest that these tufts might be a deterrent to predators, as they look like ‘eyes’ in the dark. A review of the use and occurrence of pectoral tufts in southern African sunbird species is also discussed. We suggest the ‘anti-predator’ hypothesis be investigated further.African Zoology 45(2): 342–347 (October 2010)

Bird communities in Tamhini Wildlife Sanctuary in the northern Western Ghats were studied using line transect and point count methods from the year 2011 to 2013. The updated checklist of birds at the Sanctuary is now represented by 164 bird species. The present study reported 35 new records to the area, while 15 earlier reported bird species were not observed. Overall, 55 insectivorous, 19 omnivorous, 14 granivorous, nine piscivorous, eight frugivorous, eight carnivorous and six nectarivorous species were observed. Out of these, 98 were residents, 17 winter visitors, three vagrant visitors and one was summer migrant. Four restricted range species were recorded from the Sanctuary as Nilgiri Wood Pigeon Columba elphinstonii, Malabar Grey Hornbill Ocyceros griseus, White-bellied Blue Flycatcher Cyornis pallipes and Crimson-backed Sunbird Leptocoma minima. Human activities such as pruning, cutting, grazing, fires, quarrying, trailing and camping were also reported in and around the Sanctuary.

Substantial amounts of maternal androgens are found in birds' eggs and have been shown to benefit offspring development. Within-clutch patterns of increasing androgen concentrations over the laying sequence are often hypothesized to compensate for the negative effects of hatching asynchrony. However, detrimental effects to offspring fitness of exposure to high yolk androgen levels have also been demonstrated. This suggests that mothers should forego these costs to their offspring when the need for compensation for hatching asynchrony is low or when alternative compensatory strategies, e.g. in terms of increasing egg mass, are available. Here we show that in the south-temperate lesser double-collared sunbird Nectarinia chalybea, a species with hatching asynchrony but also with high survival of last-hatched chicks, mothers do not deposit resources differentially in terms of either yolk androgen concentration or egg mass across the laying sequence. We discuss to what extend this challenges the original explanation of within-clutch variation in these egg parameters and offer some explanation for their between-clutch variation which was related to female body mass.

We review the published information on postnatal growth rates of hummingbirds (13 species), and report previously unpublished records for nine additional trochilid species. The allometric relationship based on the log10-transformed data of K (logistic growth rate constant) and body mass has a slope of −0.313 and an intercept of −0.346 (n = 22; r2 = 0.18; P = 0.049). The allometric relationship has a slope of −0.366 and an intercept of −0.327 (n = 20; r2 = 0.30; P = 0.013) if the two Nearctic records are excluded. Visual inspection suggests that higher K-values occur in Nearctic hummingbirds (x = 0.422; n = 2) compared to Neotropic species (x = 0.269; n = 20). We suggest a revival of studies collecting basic life history information such as postnatal growth rates of birds, especially of tropical taxa.

Summary Monthly mist-netting of low-flying forest birds was conducted in three lake-shore forests in southern Uganda from September 1970 to July 1972. It was found that the edge of the forest formed a distinct ecological barrier that was rarely crossed by species on either side of it. Catches were concentrated in the hours of daylight, in two peaks, a morning peak at 09.00 hrs and an afternoon peak at 16.00 hrs (sun-time) for all birds combined, although there were slight species differences. Most bird species were found to be sedentary in a fixed home-range, and covered lateral distances of up to c. 300 m. No movement between the different forests was recorded. The most common birds such as bulbuls were often caught at heights between 0·6 and 1·8 m above the ground, but the upper limit of their vertical range was not determined. It is suggested that the bi-modality of flight activity may be intrinsic, even though it may be correlated with such extrinsic factors as light and radiation. On a month to month basis, the numbers of birds caught reflected breeding and moult activity. This was best shown by the Pygmy Kingfisher, taken in higher numbers towards the end of the first rainy season when a majority of the birds caught were young and many birds were moulting the remiges. On the other hand higher numbers of Olive Sunbird were found during the second rainy season, again at a time corresponding to a general moulting of remiges. The bulbuls showed fluctuations in numbers caught that were matched by an equally fluctuating pattern of moult. The role of food as a possible limiting factor in bird breeding is discussed.

Summary Owing to the regular alternation of wet and dry seasons and to the relatively simple arrangement of vegetation zones, migration is a well-developed phenomenon in the northern tropics of Africa. Nigeria is well placed for its study. While a vast amount remains to be learned, a systematic treatment of the 672 Nigerian bird species shows that at least 126 of them are migrant. Species newly shown to be migratory include the sunbird Nectarinia pulchella, the bunting Fringillaria (Emberiza) tahapisi, and the sparrow Gymnoris (Petronia) dentata, and corroborative evidence is adduced for many more. New interpretations are placed on the movements of the bustard Neotis denhami, the Painted Snipe Rostratula benghalensis, and other species. Most families that are migrant in the temperate zone (e.g. storks, cuckoos, nightjars, hirundines) have several migrants among their tropical representatives, except flycatchers, thrushes, warblers and shrikes. Important tropical migrant families include the kingfishers and sunbirds. The following ecological correlates emerge: migration appears to be more important at lower than higher trophic levels in the ecosystem; only one primary lowland rain forest and one montane forest species migrate; 95% of African migrants in Nigeria inhabit the five savanna zones, where the 120 migrants comprise 28% of the avifauna; most savanna migrants cross one, two or three vegetation zone boundaries; few are restricted within a single zone or cross four boundaries; twice as many savanna species are eurytopic (habitat-tolerant) as stenotopic (habitat-tied), and twice the proportion of eurytopic as stenotopic species are migrant; the majority of migrants move so as to avoid the winter drought in northern Nigeria (insectivores being little affected) and also the heaviest summer rains in southern savannas; migration is initiated by climatic factors such as rains, dry desert winds, etc. Three to six Nigerian species cross the Equator, but the stork Anastomus lamelligerus is shown to breed in Nigeria and the Chad basin and may not be a trans-equatorial migrant. A quail, a crake, a coucal and five cuckoos have space-time distribution patterns (motograms) in Nigeria that suggest equatorial migration. Motograms figured for 60 species show great variation. Nearly all land-bird migrants move with the progression of the sun and the inter-tropical front, north in spring and south in autumn. The basic pattern is thus a summer wet-season range at higher latitude than the winter dry-season range, and specific patterns vary according to the absolute and relative latitudinal limits af each season, and to speed and dates of migration. Comparison of congeneric migrants having different breeding seasons or motogram patterns suggests that a specific migration pattern is fixed by ecological necessity, and reproduction occurs at that time in the year when the species is stationary longest. Breeding seasons may span migration periods, leading to two-stage early-rains migration in e.g. the kingfisher Halcyon leucocephala. Water-bird migrations are complicated by opportunist breeding and responses to floods and changing water levels in rivers. A few species move with the typical land-bird pattern; others concentrate at perennial marshes in arid northern savannas, and may disperse in all directions from the few west African breeding stations.

Summary The male Splendid Sunbird has only one song type, each note of which has a simple frequency/time profile. An analysis of the songs of males from several localities near Legon (5.63° N, 0.19° N) showed that there are clear-cut song dialects characterizing each population. Those parts of the song giving rise to dialects are the time interval between consecutive pairs of notes (the time interval pattern) and the frequency/time profile of each note. The dialects were preserved over a period of three years (the duration of the study) and there was little variation in the song of a ringed bird over a period of two months. The boundary between dialects is apparently quite sharp, occurring perhaps within a distance of 50 m. Marked geographical variation in the song occurs, and is expected because of the mosaic of dialects that presumably exist throughout the sunbird's range in southern Ghana. For dialects to be effective in keeping populations together, those characteristics of the song which give rise to dialects should be readily and quickly discerned and need not require a statistical demonstration. This condition holds for the song of the Splendid Sunbird. The results are compared with the ideas of Nottebohm (1964) and Thielcke (1969) on the maintenance and usefulness of song dialects.

Birds show considerable variation in sperm morphology. Closely related species and subspecies can show diagnostic differences in sperm size. There is also variation in sperm size among males within a population, and recent evidence from passerine birds suggests that the coefficient of inter-male variation in sperm length is negatively associated with the level of sperm competition. Here we examined patterns of inter- and intra-specific variation in sperm length in 12 species of sunbird (Nectariniidae) from Nigeria and Cameroon, a group for which such information is extremely limited. We found significant variation among species in sperm total length, with mean values ranging from 74 μm to 116 μm, placing these species within the short to medium sperm length range for passerine birds. Most of this variation was explained by the length of the midpiece, which contains the fused mitochondria and is an important structure for sperm energetics. Relative midpiece length was negatively correlated with the coefficient of inter-male variation in sperm total length across species, suggesting that sperm competition may have selected for greater midpiece length in this group. We also mapped sperm lengths onto a time-calibrated phylogeny and found support for a phylogenetic signal in all sperm length components, except head length. A test of various evolutionary or tree transformation models gave strongest support for the Brownian motion model for all sperm components, i.e. divergences were best predicted by the phylogenetic distance between lineages. The coefficients of inter-male variation in sperm total length indicate that sperm competition is high but variable among sunbird species, as is the case with passerine birds at large. The final version of this research has been published in Ibis. © 2016 Wiley

SUMMARYAlthough most birds are accustomed to making short flights, particularly during foraging, the flight patterns during these short periods of activity differ between species. Nectarivorous birds, in particular, often spend time hovering, while non-nectarivorous birds do not. The cost of short flights is likely therefore to differ between nectarivorous and non-nectarivorous birds because of the different energetic contributions of different flight types to the behaviour. The 13C-labelled bicarbonate technique was used to measure the energy cost of short flights in the nectarivorous Palestine sunbird Nectarinia osea (mean mass 6.17±0.16 g, N=8)and the non-nectarivorous starling Sturnus vulgaris (mean mass 70.11±1.11 g, N=9). The technique was initially calibrated in five individuals for each species at temperatures ranging from 1 to 35°C,by comparing the isotope elimination rate to the metabolic rate measured simultaneously by indirect calorimetry. The cost for short intermittent flight was then measured by encouraging birds to fly between two perches at either end of a narrow corridor (perch distance for sunbirds, 6 m; for starlings, 5 m), and measuring the amount of isotope eliminated during the flight. The isotope elimination rate was interpolated onto the calibration equation to predict flight cost, as a direct calibration could not be performed during flight. Mean energy expenditure during flight was 1.64±0.32 W in sunbirds, while in starlings the flight costs averaged 20.6±0.78 W. Energy cost of flight relative to basal metabolic rate was substantially greater in the starling than the sunbird. Phylogenetic analysis of different modes of flight in these and additional species suggests that differences in flight behaviour may cause these elevated costs in slow flying non-nectarivores such as starlings, compared to birds that are more prone to short intermittent flights like the sunbirds.

Male orange-tufted sunbirds (Nectarinia osea) exhibit distinct song dialects throughout Israel. Recently, two distinct local dialects with a sharp boundary were discovered in a small (1.5 km 2 ) urban neighborhood densely inhabited by 63 territorial sunbird pairs. We conducted playback experiments to determine song dialect discrimination capability by sunbird males in this neighborhood. Males of both dialects responded significantly more strongly to playback of their own dialect than to that of the adjacent dialect. In spite of the extreme proximity between the two dialect areas, we found no effect of distance to the neighboring dialect on the intensity of any the behavioral responses. We suggest that due to the complex acoustic properties of this urban neighborhood, sunbirds are extremely limited in the number of neighboring males they can assess to establish what the local song is. A stronger response to one’s own dialect is therefore expected, and we discuss how local dialects could be maintained via this mechanism regardless of the very small distances between territories and dialect populations.

Territorial behavior of the orange-tufted sunbird (Nectarinia osea Bonaparte) was studied in a suburb of Tel Aviv. Both male and female orange-tufted sunbirds occupied and guarded their territory throughout the year, but did so at different intensities in relation to season and fertility stages. When they were in the territory, both sexes spent most of their time at its center, and more so during the breeding season. Throughout the year, males tended to perch in exposed locations, while females spent 90% of their time in concealed locations. Males were also much more vocal than females, and during the breeding season they sang from high places, which females never did. It is suggested that occupying a territory during autumn may increase the chances of the territory’s owners continuing to occupy it during the breeding season. Territories were also defended and advertised during the breeding season, with the female fertility stage having a significant effect on the behavior of her male partner, whose prese...

Abstract In a study of male song in the orange-tufted sunbird (Nectarinia osea) in an urban neighborhood in Ramat-Aviv, Israel, we discovered the occurrence of song variation on a microgeographic scale in the form of two distinct dialects with a sharp boundary between them. The main distinction between the two song dialects is the frequency of the trill, which comprises the terminal part of the song. A large difference of 2-3 kHz in the peak frequency of the trill was discovered between the two dialects, which could be easily distinguished by ear. Thirtyseven males were recorded singing the 'low' dialect and 21 birds sang the 'high' dialect. Four other birds sang both dialects or 'hybrid' songs. Along the boundary that separated the two dialect populations, neighboring birds sang different dialect songs, although they were only 20-30 meters apart. All four 'bilingual' birds occupied territories near the dialect boundary. The historical processes leading to the formation of this dialect system may result from the pattern of human settlement at the time of the establishment of this neighborhood in the early 1950's. The spatial distribution of the two sunbird dialect populations, and the apparent low dispersal rates of birds from their natal dialect area, suggest the existence of a mechanism, which currently maintains these dialects at the current boundaries.

The water balance of nectarivores is tightly linked to their energy balance. When nectar is dilute, consumption of a large water excess is inevitable. We investigated energy and water balance in lesser double-collared sunbirds, Nectarinia chalybea (8 g), kept at 20 °C and fed different nectar concentrations (0.4, 0.8 M sucrose or 1.2 M sucrose). The mass of sucrose consumed, body mass, day-time mass gain and night-time mass loss were the same irrespective of diet, the birds compensating energetically for changes in sucrose concentration by drinking greater volumes of the more dilute solutions. Sunbirds consumed between 0.5 times and 1.8 times their body mass in preformed water per day, depending on sucrose concentration, and excreted around 75% of the water. The difference between water gain (preformed and metabolic water) and excreted water is assumed to equal evaporative water loss, and was similar on 1.2 M and 0.8 M sucrose, but was higher on a diet of 0.4 M sucrose. The osmolalities and K+ and Na+ concentrations of the excreted fluid were extremely low, so that sunbird urine resembled that of hummingbirds and freshwater vertebrates rather than that of typical terrestrial vertebrates. N. chalybea is able to maintain energy and water balance over a range of nectar concentrations by adjusting the volume of solution consumed and by excreting copious, dilute fluid.

SummaryOrnithological surveys were conducted in Tanzanian submontane forest at Nilo Forest Reserve in the East Usambaras and Nguu North Forest Reserve in the Nguu Mountains in July-September 1995. Information on the ecology of poorly known bird species of conservation interest was collected and combined with previously published information to assess their conservation status. Sixteen species of conservation interest were recorded during fieldwork, including five Vulnerable (Usambara Eagle Owl Bubo vosseleri, East Coast Akalat Sheppardia gunningi, Amani Sunbird Anthreptes pallidigaster, Banded Green Sunbird Anthreptes rubritorques and Usambara Weaver Ploceus nicolli); three Near-threatened (Southern Banded Snake Eagle Circaetus fasciolatus, Fischer's Turaco Tauraco fischeri and Moreau's Sunbird Nectarinia moreaui); one regionally Endangered (Southern Hyliota Hyliota australis); one regionally Vulnerable (Uluguru Violet-backed Sunbird Anthreptes neglectus), two regionally Near-threatened (Lemon Dove Aplopelia lavata and Evergreen Forest Warbler Bradypterus barratti); and 10 in total as restricted-range species (Fischer's Turaco, Usambara Eagle Owl, Sharpe's Akalat Sheppardia sharpei, Red-capped Forest Warbler Orthotomus metopias, Spot-throat Modulatrix stictigula, Amani Sunbird, Banded Green Sunbird, Moreau's Sunbird, Kenrick's Starling Poeoptera kenricki and Usambara Weaver). New information on the ecology of these species is presented in this paper. It is recommended that the conservation status of East Coast Akalat and Uluguru Violet-backed Sunbird be changed to globally Near-threatened and regionally Near-threatened, respectively. Should further work confirm that the Usambara race of Southern Hyliota deserves specific status it is strongly recommended that it be considered globally Endangered. All other species recorded should retain their current status and continue to be monitored. The Nguus represented a new locality for several species. Sharpe's Akalat, Spot-throat, Red-Capped Forest Warbler, otherwise widely distributed throughout the east Tanzania, were absent from the Nguus.

The oxygen consumption (VO2) of the lesser double-collared sunbird, Nectarinia chalybea. was measured at ambient temperatures (Ta) from 7 to 35°C. The diel variation in body temperature (Tb) and wet thermal conductance (C) was also determined. The sunbirds (mean mass 8,36 g ± S.E. 0.21 g) showed a pronounced diel cycle of VO2, with a mean reduction of 50% at night. Basal metabolic rate was estimated to be 3.23 ml O2/g.h, which is 88% of the predicted value for a passerine bird of this size. There was a mean reduction in Tb of 3.6°C at night. Both day and night values of Tb decreased with decreasing Ta, as did individual values of C. Winter breeding in the south-west Cape is energetically stressful for lesser double-collared sunbirds, but they have the physiological capacity to reduce their energy expenditure substantially at night.

We describe a new species of sunbird, Aethopyga linaraborae, known from Mt. Mayo, Mt. Puting Bato, and Mt. Pasian, all part of an isolated range of mountains in eastern Mindanao, Philippines. It occurs commonly in mossy forest from about 1,200 m and above. We also describe a new subspecies of Apo Sunbird, Aethopyga boltoni tibolii, known from Mt. Busa and Mt. Matutum of southern Mindanao, where it is found in mossy forest above 1,000 m. Received 23 April 1996, accepted 1 August 1996. MINDANAO (97,923 km2) is the second largest of the more than 7,100 islands that comprise the Philippine Archipelago (see Fig. 1). Of the 341 species of birds that have been recorded from the island, 248 are residents, 89 are migrants or accidentals, and 4 have both resident and migrant populations. Among the residents, 20 are endemic to Mindanao and its adjacent landbridge islands of Basilan, Dinagat, and Siargao; 75 are endemic to the Philippines; and 153 are more widely distributed (duPont 1971, Dickinson et al. 1991). Dickinson et al. (1991) summarized the ornithological exploration of Mindanao that began in 1771 or 1772 when Sonnerat (1776) visited Zamboanga in western Mindanao. By the close of the 19th century, many lowland areas had been explored, yielding only five of the endemics, and a few naturalists had climbed Mindanao's highest peak, Mt. Apo (2,938 m), without obtaining any of its rich montane avifauna. However, most of Mindanao's endemic birds are mid-elevation or montane species, and with but one exception, all were discovered within this century (Table 1). In response to growing concern over deforestation and the status of the fauna of the archipelago, the National Museum of the Philippines (NMP) and Cincinnati's Museum of Natural History and Science (CMNH) initiated the Philippine Biodiversity Inventory (PBI) in 1989 to survey remaining forested areas. The PBI focused on sites that either were poorly known or never had been studied by naturalists. In 1993, the PBI team conducted surveys on three Mindanao mountains (see Fig. 1): Mt. Apo, Mt. Busa, and Mt. Puting Bato (the name used locally; on most maps it is Mt. Tagub). Among the many important discoveries of the Mindanao surveys were specimens of what appeared to be two unique populations (one from Mt. Busa in southern Mindanao and one from Mt. Puting Bato in eastern Mindanao) of the Apo Sunbird (Aethopyga boltoni), a Mindanao endemic represented by the subspecies A. b. boltoni (Mearns 1905) and A. b. malindangensis

We document the discovery of the first population of greater double-collared sunbird ( Cinnyris afer complex) from the Eastern Arc Mountains of Tanzania. We assessed phylogenetic relationships and taxonomic rank based on mtDNA sequence data, nine microsatellite loci and morphology. This new taxon, locally distributed in the Rubeho and Udzungwa Highlands, has close affinities (< 1% uncorrected sequence divergence) with C. w hytei (split here from C . ludovicensis) of the Nyika Plateau in Malawi, but differs in having longer tarsi and in subtle plumage details. Although the birds from Nyika and Udzungwa-Rubeho are reciprocally monophyletic for mitochondrial DNA, coalescent analyses of the microsatellite data and the total molecular dataset could not reject the possibility of continued gene flow between the two populations. Thus, although we favour the phylogenetic species concept, we adopt a cautious approach and formally describe the Rubeho and Udzungwa greater double-collared sunbird population as a subspecies of Cinnyris whytei. This new sunbird taxon has been recorded only above 1700 m in scrub on the forest/grassland ecotone in a very restricted area in the Rubeho and Udzungwa Highlands of Tanzania. The effects of human settlement and agriculture threaten this taxon.

Using the single-sample variant of the doubly labeled water method (DLW), I quantified the field metabolic rate (FMR) and water flux of female Orange-breasted Sunbirds (Nectarinia violacea) during the incubation period. Concurrent to DLW measurements, I examined their incubation behavior and microclimate. These are the first measurements of FMR and water flux for a nectarivorous bird during incubation and the first for an Old World sunbird species. For 10 incubating female Orange-breasted Sunbirds (mean mass = 9.5 g), CO2 production averaged 13.3 ml/hr, which corresponds to a FMR of 66.2 kJ/day, one of the highest values reported for a bird of its size. Among female passerines, the ratio of FMR to basal metabolic rate (BMR) is typically near 3.0, but for female Orange-breasted Sunbirds, the ratio of FMR/BMR is near 6.5. This suggests that during incubation females are working near their maximum capacity. Females generally lost mass during experimental periods; birds with high mass loss have elevated FMRs. Females consumed 14.7 ml H20/ day, slightly more than twice that expected based on body size. Attentiveness of females averaged 39.4 min/hr, while incubation bouts and inattentive periods averaged 11.9 min and 6.7 min, respectively. Females stayed away from their nests for long periods in the late afternoon, especially during inclement weather. Egg temperature averaged 34.7?C for all experimental periods combined. When females were absent for extended periods, eggs cooled to ambient temperatures, often near 100C. This is a temperature well below the physiological zero temperature. The FMR of females increased significantly with decreasing operative temperature. One observation suggested that when in negative energy balance, females lower their body temperature while on the nest at night. These are the first data suggesting that sunbirds use hypothermia as an energy conservation mechanism in the field.

(1991). Growth and Development of the Yellow-bellied Sunbird Nectarinia jugularis in North Queensland. Emu - Austral Ornithology: Vol. 91, No. 1, pp. 58-61.

Plant nectar is a simple food consumed by many different animals. Preferences regarding its components, especially sugars, have been studied for many species, but the preferences of nectar-feeding birds for different sugar concentrations are less well known than their sugar type preferences. The concentration preferences of white-bellied sunbirds, Cinnyris talatala, were examined using paired solutions of either sucrose or equicaloric 1:1 mixtures of glucose and fructose. Preferences were tested over a broad concentration range of 0.25-2.5 M sucrose equivalents (using 0.25 or 0.5 M differences between pairs). On both sucrose and hexose diets, the higher concentration was preferred up to 1 M, but there were no significant preferences above this concentration, except that birds preferred 1.5 to 2 M sucrose. As with other nectar-feeding vertebrates, the laboratory preferences of sunbirds do not explain the low concentration of their natural nectars. We recorded apparent excess sugar consumption during 6 h preference tests involving concentrated hexose diets; this could be due to digestive constraints or viscosity differences between sucrose and hexose solutions.

Nectarivorous birds encounter varying nectar concentrations while foraging on different food plants and must adjust their consumption to maintain constant energy intake. We determined how rapidly captive whitebellied sunbirds (Cinnyris talatala) adjust their volumetric intake and feeding patterns after changes in diet concentration. On four consecutive days, birds were fed sucrose diets alternating between a standard diet of 16% w/w and test diets of 2.5, 8.5, 16 or 30% w/w, respectively, for 1.5 h periods. Feeding events were recorded with an infrared photo-detection system and food intake and body mass were monitored continuously by electronic balances interfaced to a computer. Generally, birds demonstrated a measurable increase in feeding frequency and food intake within 10 min after a decrease in sucrose concentration. However, individuals responded differently to the most dilute diet (2.5%): while most increased their food intake, others stopped feeding for a short while, appearing to dislike this diet. Furthermore, the number and duration of feeding events increased in the first 5 min after the switch from 2.5% back to 16%, as the birds attempted to compensate for previous reduced sugar intake. Daily sugar intake was lower when birds alternated between 2.5 and 16% diets than on other test days, but birds were able to maintain body mass, presumably through behavioural adjustments.

Trypanosoma naviformis n. sp. is described from the African olive sunbird Cyanomitra olivacea in Ghana based on the morphology of its hematozoic trypomastigotes and partial sequences of the small subunit ribosomal RNA gene. This parasite belongs to the group of small non-striated avian trypanosomes (< 30 µm in length in average) with the kinetoplast situated close to the posterior end of the body. Trypanosoma naviformis can be distinguished from other small avian trypanosomes due to its poorly visible flagellum, central position of its nucleus, and the symmetrically (in relation to the nucleus) narrowing of both ends of the hematozoic trypomastigotes, which are boat-like in shape. Illustrations of trypomastigotes of the new species are given, and SSU rDNA lineages associated with this parasite are documented. This parasite has been reported in Ghana and Cameroon and was also found in the yellow-whiskered greenbul, Andropadus latirostris in these countries. It appears to be widespread in its range given the distribution of these bird species in Africa.

SUMMARY Avian nectarivores show compensatory feeding by adjusting their volumetric intake in response to variation in nectar concentration. This study used an infrared photo-detection system to investigate the short-term feeding patterns of whitebellied sunbirds (Nectarinia talatala) consuming three different sucrose concentrations (10, 20 and 30% w/w). Sunbirds increased their feeding frequency on the most dilute diet, but there was no change in feeding duration. Thus, the increase in total time spent feeding on the dilute diet was due to the increased feeding frequency. No difference in short-term feeding patterns was found between the 20% and 30% diets. Total time spent feeding was extremely short on all diets (96-144 s in every hour). Birds maintained the same steady increase in body mass over the course of the day on all three diets. Daily rhythms in feeding patterns were evident, with longer feeding duration and lower feeding frequency in the early morning and evening than during the rest of the day. Because ingestion rates on a particular diet may vary through the day, caution must be exercised in using feeding duration as a surrogate for meal size. Individual birds varied greatly in their feeding patterns irrespective of diet concentration.

The Eastern Arc Mountains of East Africa are known for an exceptionally rich flora and fauna with very high endemism. For the conservation of rare forest birds these mountains are of the utmost importance in Africa. We provide the first population estimate of the endemic Loveridge's Sunbird Nectarinia loveridgei in the Uluguru Mountains of eastern Tanzania. Our study was conducted between September and December 2000. Capture-recapture using mistnets was used to gather data at eleven study sites between 1,300–2,600 m altitude in four different areas of the Ulugurus. The program CAPTURE was used to estimate the population at each study site. Since the home range of Loveridge's Sunbird is unknown, the density of the potential population was calculated by assuming home ranges ranging from 0 km2 through to 3 km2. When combined with data on the forest area in the Ulugurus and fixing the lower and upper home range sizes for this species at 0.1 km2 and 0.8 km2, we obtain an estimated total population ranging from 21,000 to 166,000 individuals. A median home range of 0.45 km2 estimates the population close to 37,000 individuals. The species does not seem threatened but its long-term survival will depend on the survival of the forest, and in particular on how well the forest reserves on the Ulugurus are managed in the future.

SUMMARY Water intake of nectarivores is intrinsically linked to nectar concentration. Osmoregulation in whitebellied sunbirds Nectarinia talatala (body mass 9.3±0.1 g, mean ± S.D., N=7),was examined by feeding them sucrose solutions, equivalent to extreme diet concentrations (0.07–2.5 mol l–1 sucrose; 2–65%w/w), with and without supplementary drinking water. Total water gain was 33–515% of body mass daily. Cloacal fluid (CF) volume increased with diet dilution from 0.4% to 309% of body mass while increases in evaporative water loss (obtained by difference) were also recorded. Osmolality of CF demonstrated the largest scope yet recorded for a bird and was significantly correlated with water flux: mean values were 6–460 mosm kg–1 H2O (minimum 3, maximum 1900 mosm kg–1). When supplementary water was provided, its consumption by birds fed concentrated diets (2.5 mol l–1 sucrose) led to a dramatic reduction in CF osmolality, from 461±253 to 80±119 mosm kg–1 fluid. Sunbirds maintained energy balance on sucrose diets varying tenfold in concentration, from 0.25 to 2.5 mol l–1; however, on extremely dilute diets (0.07 and 0.1 mol l–1 sucrose, lower than natural nectar concentrations) their inability to maintain energy balance was probably due to excess preformed water. Total osmotic excretion and concentrations of Na+ and K+ increased with high water fluxes, and are a possible physiological constraint for nectarivorous birds on artificial dilute diets devoid of electrolytes. Even low electrolyte levels in nectars may be adequate to replace these losses, but other physiological limitations to the intake of dilute nectars are increased energetic costs of solute recovery, increased heat loss and interference with digestive processes. Sunbirds therefore deal with sugar solutions spanning the range of nectar concentrations by shutting down water excretion on concentrated diets, or, on dilute diets, by producing extremely dilute CF with some of the lowest solute concentrations recorded.

SUMMARY Nectar-feeding of birds was recorded during a phenological study of the woody vegetation at Zaria in the Northern Guinea Savanna of Nigeria. Throughout the dry season when it is in a non-breeding state, the Scarlet-breasted Sunbird Nectarinia senegalensis concentrates on the ornithophilous plants which flower in an overlapping sequence, and exploits the smaller-flowered species less frequently. As the flowering of the ornithophilous species decreases at the end of the dry season, the range of other plants exploited increases but, in the early rains as the flowering of the indigenous plants tails off, the sunbird switches to ornamental exotics and the indigenous, shrubby parasite, Tapinanthus globiferus. The bird is more conspicuously insectivorous during the wet season when it breeds. The Pygmy Sunbird Anthreptes platura is a breeding, dry-season visitor which exploits a somewhat different range of small-flowered, mainly entomophilous species and some exotics but also takes nectar from those ornithophilous species it can exploit, as well as the chiropterophilous Parkia clappertoniana. The bulk of the breeding population leaves the district before the flowering of the indigenous plant tails off. The five other species of sunbird recorded in the district are either very rare residents or more numerous wet-season visitors and passage migrants for which records of nectar-feeding are too few to draw conclusions about seasonal changes but the wet-season visitors appear to rely on the garden exotics in the comparative absence of flowering indigenous plants. Nectar-feeding on Bombax costatum and Parkia clappertoniana, where nectar is readily accessible and present in relatively large quantities, was noted for IS species of non-nectariniid birds, some of which were regular visitors. Some examples of flower consumption probably related to nectar-feeding are also mentioned.

The haemoproteids of the sunbird family Nectariniidae are reviewed on the basis of material obtained from throughout the distributional range of the family. Variability in the 19 morphometric parameters used to define haemoproteid species were studied (i) over time in the same individual host; (ii) between individual hosts of the same species; (iii) between hosts of different species; and (iv) between hosts from different geographic regions. Statistical analyses indicated that the morphology of the parasites remained remarkably constant and the degree of variability noted was of the same order of magnitude for parasites within a single smear, between individual and different species of hosts, and between hosts from different regions. All parasites studied were morphologically similar and represented a single species, Haemoproteus sequeirae Tendeiro, 1947. Haemoproteus raymundi de Mello and Raimundo, 1934, is declared incertae sedis.

The full song of the yellow-bellied sunbird (Nectarinia venusta) comprises distinct phrases, which retain their typical three-part structure and temporal organization regardless of the concentration of the sucrose solution provided. However, the sugar concentration does affect the types of elements that make up the initial part of the phrase and the number of elements in the terminal part. Several types of elements may be produced either as separate calls or as components of the initial part of the phrase; as the concentration decreases, at least two of these element types occur progressively more often in the phrases, taking the place of others.

Different concentrations of a sucrose solution vary the courtship song and behaviour of the male yellow-bellied sunbird Nectarinia venusta- the duration of subsong, total singing duration, and the absolute number of full song phrases. With high concentrations the sunbird sings more full song phrases but less subsong during the courtship season than otherwise. The various effects are described.

Allohymenolepis palawanensis sp. n. from a yellow-breasted sunbird, Nectarinia jugularis, in Palawan, Republic of the Philippines, is characterized by possessing a sucker diameter of 52–56 μm, a scolex of 120 × 157–166 μm, ovary 25–40 × 71–90 μm, and a vitelline gland of 17–25μm

Hypogramma hypogrammica is an aberrantly-plumaged Malaysian sunbird usually allied to Anthreptes "on account of the straight keel of the lower mandible" (Shelley 1878) or Nectarinia on account of "its general coloration and apparently primitive nature" (Delacour 1944). In the most recent revision of the Nectariniidae, Rand (1967a) considered Hypogramma a monotypic genus which he placed between Anthreptes and Nectarinia. Hypogramma hypogrammica is dull olive green in color, somewhat yellower below with bold streaking on most of the underparts, resembling in this respect certain Arachnothera (A. juliae for example) and certain female Nectarinia such as N. johannae. Iridescent coloration is restricted to males, which have a purple crescent on the nape and similar purple coloration on the lower back and upper tail coverts. Often concealed on study skins and rarely remarked upon are (in the male only) elongated tufts of white feathers at the base of the lower back. The pattern of metallic coloration, especially the nuchal patch, is unlike any other sunbird, although several species of Anthreptes have similar purple lower backs. Because Aethopyga-Arachnothera sunbirds are easily distinguished from Nectarinia and Anthreptes by their tongue tip structure (Scharnke 1932; Delacour 1944), I wanted to examine the tongue of Hypogramma to establish its affinities with AnthreptesNectarinia. W. E. Lanyon kindly gave me permission to remove for examination the tongue from a skin of Hypogramma hypogrammica intensior (AMNH 685539) in the collections of the American Museum of Natural History. The tongue of most sunbird species is for the major part of its length a closed tube formed by inward rolling and meeting of the edges (see cross sections in Skead 1967:28). The tongue tip is split and bitubular, but it lacks elaborate fimbriation. Virtually all species of sunbirds that have been examined have similar tongues; I have personally examined the tongues of 12 sunbird species in addition to those 23 species listed by Gardner (1925), Scharnke (1932), and Skead (1967). Aethopyga and Arachnothera difEXPANDED TIP (2x)