Hummingbird Species Research Articles

Species traits explain public perceptions of human-bird interactions.

The impacts of urbanization on bird biodiversity depend on human-environment interactions that drive land management. Although a commonly studied group, less attention has been given to public perceptions of birds close to home, which can capture people's direct, everyday experiences with urban biodiversity. Here, we used ecological and social survey data collected in the metropolitan region of Phoenix, Arizona, USA, to determine how species traits are related to people's perceptions of local bird communities. We used a trait-based approach to classify birds by attributes that may influence human-bird interactions, including color, size, foraging strata, diet, song, and cultural niche space based on popularity and geographic specificity. Our classification scheme using hierarchical clustering identified four trait categories, labeled as Metropolitan (gray, loud, seedeaters foraging low to ground), Familiar (yellow/brown generalist species commonly present in suburban areas), Distinctive (species with distinguishing appearance and song), and Hummingbird (hummingbird species, small and colorful). Strongly held beliefs about positive or negative traits were also more consistent than ambivalent ones. The belief that birds were colorful and unique to the regional desert environment was particularly important in fortifying perceptions. People largely perceived hummingbird species and birds with distinctive traits positively. Similarly, urban-dwelling birds from the metropolitan trait group were related to negative perceptions, probably due to human-wildlife conflict. Differences arose across sociodemographics (including income, age, education, and Hispanic/Latinx identity), but explained a relatively low amount of variation in perceptions compared with the bird traits present in the neighborhood. Our results highlight how distinctive aesthetics, especially color and song, as well as traits related to foraging and diet drive perceptions. Increasing people's direct experiences with iconic species tied to the region and species with distinguishing attributes has the potential to improve public perceptions and strengthen support for broader conservation initiatives in and beyond urban ecosystems.

Floral phenology of an Andean bellflower and pollination by buff-tailed sicklebill hummingbird.

The Andean bellflowers comprise an explosive radiation correlated with shifts to specialized pollination. One diverse clade has evolved with extremely curved floral tubes and is predicted to be pollinated exclusively by one of two parapatric species of sicklebill hummingbirds (Eutoxeres). In this study, we focused on the floral biology of Centropogon granulosus, a bellflower thought to be specialized for pollination by Eutoxeres condamini, in a montane cloud forest site in southeastern Peru. Using camera traps and a pollination exclusion experiment, we documented E. condamini as the sole pollinator of C. granulosus. Visitation by E. condamini was necessary for fruit development. Flowering rates were unequivocally linear and conformed to the “steady‐state” phenological type. Over the course of >1800 h of monitoring, we recorded 12 E. condamini visits totaling 42 s, indicating traplining behavior. As predicted by its curved flowers, C. granulosus is exclusively pollinated by buff‐tailed sicklebill within our study area. We present evidence for the congruence of phenology and visitation as a driver of specialization in this highly diverse clade of Andean bellflowers.

Behavioural and morphological traits influence sex-specific floral resource use by hummingbirds.

Research on resource partitioning in plant-pollinator mutualistic systems is mainly concentrated at the levels of species and communities, whereas differences between males and females are typically ignored. Nevertheless, pollinators often show large sexual differences in behaviour and morphology, which may lead to sex-specific patterns of resource use with the potential to differentially affect plant reproduction and diversification. We investigated variation in behavioural and morphological traits between sexes of hummingbird species as potential mechanisms underlying sex-specific flower resource use in ecological communities. To do so, we compiled a dataset of plant-hummingbird interactions based on pollen loads for 31 hummingbird species from 13 localities across the Americas, complemented by data on territorial behaviour (territorial or non-territorial) and morphological traits (bill length, bill curvature, wing length and body mass). We assessed the extent of intersexual differences in niche breadth and niche overlap in floral resource use across hummingbird species. Then, we tested whether floral niche breadth and overlap between sexes are associated with sexual dimorphism in behavioural or morphological traits of hummingbird species while accounting for evolutionary relatedness among the species. We found striking differences in patterns of floral resource use between sex. Females had a broader floral niche breadth and were more dissimilar in the plant species visited with respect to males of the same species, resulting in a high level of resource partitioning between sexes. We found that both territoriality and morphological traits were related to sex-specific resource use by hummingbird species. Notably, niche overlap between sexes was greater for territorial than non-territorial species, and moreover, niche overlap was negatively associated with sexual dimorphism in bill curvature across hummingbird species. These results reveal the importance of behavioural and morphological traits of hummingbird species in sex-specific resource use and that resource partitioning by sex is likely to be an important mechanism to reduce intersexual competition in hummingbirds. These findings highlight the need for better understanding the putative role of intersexual variation in shaping patterns of interactions and plant reproduction in ecological communities.

Genetic relatedness and morphology as drivers of interspecific dominance hierarchy in hummingbirds.

A dominance hierarchy is the set of ranks occupied by species within an assemblage. Species with a high position within the dominance hierarchy tend to dominate subordinate species in contests for access to resources. In hummingbirds, greater weight and wing disc loading have been associated with highest ranks within the dominance hierarchy. Nevertheless, the limit to which the difference between the weight of contending species represents a competitive advantage has not yet been determined. Here, we determined the dominance hierarchy of a hummingbird assemblage exploiting the most abundant floral resource (Palicourea padifolia, Rubiaceae) in a cloud forest of central Veracruz, Mexico. Specifically, we tested whether species weight and wing disc loading influence the dominance hierarchy. Additionally, we tested whether the flowers visited per foraging bout increases with species weight and dominance. We further tested whether weight, wing disc loading, and the genetic relatedness between contenders influenced the dominance relationships in species-pair interactions. Our results indicate that the hierarchy is positively influenced by weight. Hummingbirds visited similar number of flowers regardless their weight or their dominance. Nevertheless, the probability that the heaviest contender won contests was positively associated with the differences of weight and genetic relatedness between contenders. Contrarily, the probability that the contender with greatest wing disc loading won contests was positively associated with differences of weight and negatively associated with the relatedness between contenders. However, these models only explained between 22% and 34% of the variation, respectively. Our results demonstrate that the weight was the major contributor to high dominance values. However, future studies should include (1) the temporal variability of the weight and (2) experimental predictor variables such the burst power of the hummingbirds to evaluate its effects on the dynamics of dominance hierarchies in hummingbird assemblages. All the hummingbird species present in the studied assemblage have developed wide behavioral mechanisms that compensate their morphological differences, which allow them to coexist, even when they compete for the access to the same resource.

K-mer analysis shows hybrid hummingbirds perform variable, transgressive courtship sequences

Behaviours are challenging to describe. Here, we apply k-mer analysis to characterize complex courtship behaviours at four hierarchical levels: elements, displays, bouts and repertoires, on two species of hummingbirds and their hybrids. During courtship, male rufous hummingbirds, Selasphorus rufus, perform three types of displays: shuttles (S), half pendulums (H) and rufous dives (R), while Allen's hummingbirds, Selasphorus sasin, perform four displays: S, H, Allen's dives (A) and the pendulum (P). Here we explore the behavioural sequences expressed by their hybrids, on a sample of displays from 35 Allen's hummingbirds and 46 rufous hummingbirds sampled far from their hybrid zone, compared against 306 wild male birds from a hybrid zone in Oregon and California, U.S.A. Among Allen's hummingbirds, hybrids and rufous hummingbirds, there was almost no variation in the kinematic elements that comprised displays. By contrast, the displays themselves, display sequences and repertoires varied substantially among these three groups. Some hybrids performed transgressive display variants in which kinematic elements of typical displays were missing or duplicated. This transgressive segregation implies the displays are under oligogenic control. We analysed display sequences using k-mer analysis, in which we binned display sequences into 3-mers (sequences of three). Typical 3-mers for Allen's hummingbirds included sequences PPP, PPA and SHP while typical 3-mers for rufous hummingbirds included SHR and RRR. The most defining characteristic of certain hybrids was their sequence variability: the display repertoire of some hybrids encompassed the repertoire of both parent species (e.g. performed both PPA and RRR) as well as 3-mer sequences never observed in either parent such as PRA. Such high within-individual variability in hybrid phenotype differs from how modular morphological traits (such as flowers, feathers or hair) are expressed in hybrids. This within-individual variability may be unique to behaviour.

Why is the Shaw's Agave (Agave shawii subsp. Shawii) Not Reproducing? Investigating a Rare Species' Pollination and Germination in a Fragmented Urban Park

Shaw's Agave (Agave shawii subsp. shawii) is a rare plant found in only a handful of occurrences within the extreme southwestern corner of the USA in a highly urbanized region. Seedling recruitment of Shaw's Agave in California is visibly low, and viable seed production appears to have been very low in recent years, and has been identified as a primary threat to the persistence of these populations. We performed pollination trials, seed germination studies, and inventoried floral visitors and potential pollinators (including the collection of invertebrates) to determine if pollination and/or germination failure is limiting reproduction. We placed bat detectors and camera traps near blooming agaves, and observed bird and insect visitation to the flowers. Pollination treatments included hand pollination with cross-individual and selfing trials. Our results found a low amount of seed produced per fruit across the pollination trials. Seedling herbivory was also very high (85% and 100%) in the two treatments. The combination of low seed set and high herbivory may help explain the lack of recruitment observed at multiple sites in recent years. No nectar feeding bats utilized the Shaw's agave in our study area. The only significant insect visiting flowers was the honey bee (Apis mellifera), which gathered nectar without touching the anthers. Hummingbird species were also frequent visitors but generally avoided touching the agave anthers. Only the Hooded Oriole (Icterus cucullatus), a migratory bird, appeared to regularly visit flowers for their nectar, while standing on the flowers and brushing against the anthers, potentially providing some pollination but only for plants blooming during the period the oriole is present in the region. Seedling predation was significant, and poses a considerable threat to this population. Further research into seed set and pollination treatments is recommended.

Shallow torpor keeps hummingbirds on their toes when conserving energy

Keeping warm is costly, especially when paired with one of the world's fastest lifestyles. During the day, hummingbirds zip about feeding on sugar-rich nectar to fuel their high-octane existence, but at night, the aeronautic acrobats must conserve energy, slipping into a miniature form of hibernation, known as torpor; many drop their body temperature to around 10°C and some get even chillier. But animals that use torpor are in danger from predators, so some minimise the risk by entering a shallower version from which they can emerge more rapidly. However, it wasn't clear to Anusha Shankar (Cornell University, USA), Catherine Graham (Swiss Federal Research Institute) and Donald Powers (George Fox University, USA) whether birds are also capable of using both shallow and deep types of torpor, either to avoid incurring the costs of deep torpor or as an intermediate step along the way. To find out, Shankar with Powers, Isabelle Cisneros and Sarah Thompson, also from George Fox University, headed to the Chiricahua Mountains of Arizona, USA – home to many migrating hummingbirds during spring and summer – to find out how the energetic birds deal with cold nights.‘We studied three species of hummingbird: tiny black-chinned hummingbirds [3 g], the blue-throated mountain-gem [8 g] and Rivoli's hummingbird [7 g]’, says Shankar, who trapped the wild birds by carefully dropping a net over them as they feasted at a feeder during the hour before sunset. Then, the team gently placed each hummingbird in a chamber positioned outside on a table next to a window, allowing the bird to settle before recording the temperature of its eye every 10 min using an infrared camera located in the window to find out how the animal's body temperature varied as it conserved energy overnight.Monitoring the air temperature, which ranged from 3 to 23°C, the team even recorded one particularly cold night when there was frost and the mercury fell to −1°C. They then analysed the body temperature of the birds and could see that they were quite warm as they settled down for the evening, with eye temperatures stabilising between 29 and 31°C. However, as the night progressed and the air temperature fell, the birds’ body temperature began to decline also, with all of the tiny black-chinned hummingbirds (Archilochus alexandri) dropping into deep torpor for approximately half of the night, with body temperatures below 20°C. However, the larger blue-throated mountain-gems (Lampornis clemenciae) maintained their warm evening body temperature for two-thirds of the night, only allowing their bodies to decline slightly below 30°C as they fell into shallow torpor for a quarter of the night; they rarely fell into deep torpor. Meanwhile, the Rivoli's hummingbirds (Eugenes fulgens) seemed to take an equally nonchalant approach to conserving energy. Although half of the birds resorted to deep torpor, with body temperature around 10°C for ∼20% of the night, 10 of the 12 birds dipped into shallow torpor for about a third of the night.So, hummingbirds are capable of selecting how torpid they become, suggesting that the costs associated with falling into deep torpor may sometimes outweigh the energy conservation benefits. ‘For example, torpid birds in trees might be more conspicuous than a mammal concealed in a burrow that can use deep torpor all the time’, says Shankar, explaining that hummingbirds in shallow torpor can warm up and become fully alert within a matter of seconds to evade predators, in contrast with hummingbirds that have descended into deep torpor, which may take up to half an hour to recover. ‘This makes shallow torpor more effective than deep torpor in some situations’, Shankar concludes.

A heterothermic spectrum in hummingbirds.

Many endotherms use torpor, saving energy by a controlled reduction of their body temperature and metabolic rate. Some species (e.g. arctic ground squirrels, hummingbirds) enter deep torpor, dropping their body temperature by 23-37°C, while others can only enter shallow torpor (e.g. pigeons, 3-10°C reduction). However, deep torpor in mammals can increase predation risk (unless animals are in burrows or caves), inhibit immune function and result in sleep deprivation, so even for species that can enter deep torpor, facultative shallow torpor might help balance energy savings with these potential costs. Deep torpor occurs in three avian orders, but the trade-offs of deep torpor in birds are unknown. Although the literature hints that some bird species (mousebirds and perhaps hummingbirds) can use both shallow and deep torpor, little empirical evidence of such an avian heterothermy spectrum within species exists. We infrared imaged three hummingbird species that are known to use deep torpor, under natural temperature and light cycles, to test whether they were also capable of shallow torpor. All three species used both deep and shallow torpor, often on the same night. Depending on the species, they used shallow torpor for 5-35% of the night. The presence of a heterothermic spectrum in these bird species indicates a capacity for fine-scale physiological and genetic regulation of avian torpid metabolism.

Redes de beija-flor-planta em campos rupestres e florestas ripárias em áreas de altitude do Parque Nacional da Serra da Canastra, Minas Gerais, Brasil

Abstract: Hummingbirds are specialized in consumption of nectar and play an important role in Neotropical plant communities acting as pollinator organisms. Despite the importance of this mutualistic interaction, studies about hummingbird-plant relationships remain scarce regarding the Cerrado domain (Brazilian savanna). In this study, we aimed to describe the interaction network between hummingbirds and plants in rupestrian fields and riparian forests located in altitudinal areas of the Serra da Canastra National Park. We established two transects in each phytophysiognomy, that were sampled monthly for four days, from November 2018 to October 2019. Flowering plants in each transect were observed each survey, and all the visiting hummingbirds were recorded. Networks were constructed using the R bipartite package, considering each phytophysiognomy type, and grouping data of both environments. From these three network arrangements, we extracted complementary metrics at the community level (modularity, nestedness, and network specialization index), and at the species level (species specialization index and species strength in the network). We recorded 647 interactions between 10 hummingbird species and 23 flowering plant species. The hummingbird Colibri serrirostris was responsible for most of observed bird-plant interactions and the plant Qualea cordata was the most visited. The general network was significantly modular, comprising four modules, and showed considerable high specialization and low nestedness. The interaction network in the rupestrian field showed a higher specialization, nestedness, and modularity index when compared to riparian forests, while the metrics of this ecosystem did not differ from those of the general network. However, the metrics at hummingbird species level did not differ significantly between phytophysiognomies. This study corroborated some findings about hummingbird-plant networks in other areas of the Cerrado domain, but also pointed idiosyncrasies in networks of the investigated phytophysiognomies, especially the rupestrian fields.

Citizen Science for the Knowledge of Brazilian Birds: Breeding Aspects of the Horned Sungem (Heliactin bilophus) (Aves, Trochilidae) in the Brazilian Cerrado

Photographic records produced by citizen scientists have been used by professional ornithologists to study tropical birds. Near 90 species of hummingbirds occur in Brazil, and few of them have had aspects of their breeding investigated in detail. The Horned Sungem Heliactin bilophus is a small hummingbird commonly found in central Brazil, and remains poorly known. This study aimed to investigate breeding aspects of H. bilophus in the Brazilian Cerrado through the use of citizen science data. Searches for photographic records were conducted in three online databases in April 2022. Records with evidences of breeding activities (n = 35) were obtained by citizens along 15 years, and included in this study. Most of them (89%) were obtained in the WikiAves database. They were obtained mainly in central and southeastern Cerrado. Nests were cup-shaped, and fixed to forking branches of shrubs. Most records involved nests, while a minor portion referred to young photographed outside nests. Only female adults were associated with nests or young. Clutch size was always two eggs (n = 6). One or two young were found per nest (n = 10). Most records (66%) occurred in the dry season, and fewer of them (34%) were obtained in the rainy season. They were concentrated during the whole dry season, and the late rainy season, having occurred scarcely in other periods of the year. Each phase of the breeding season (nest building, nests with eggs, downy young, greenish young in nests, and fledged young) lasted for 5-7 months. The breeding season of the Horned Sungem in the Brazilian Cerrado comprises at least 10 months, a period much longer than that considered in previous literature. This study suggests that photographic records available in citizen science databases can improve the knowledge of breeding aspects of hummingbird species found in Brazil.

A possible interspecific feeding event of two hummingbird species in southeast Mexico

We documented a potential interspecies feeding event between 2 species of hummingbirds in southeastern Mexico in 2019. We used morphological and behavioral traits to identify the hummingbirds as an adult female White-bellied Emerald (Chlorestes candida) and a juvenile Rufous-tailed Hummingbird (Amazilia tzacatl). We ruled out the possibility of hybridization due to a lack of intermediate traits in the juvenile hummingbird, which allowed for the speculation of 4 interspecies behavioral mechanisms: brood parasitism, courtship feeding, simultaneous multiple nesting, or alloparental care of young. Due to the complexity of the first 3 mechanisms and lack of documented evidence of the behaviors between the 2 species of hummingbirds, the most likely mechanism to explain the observed behavior is alloparental care of young by an inexperienced adult female White-bellied Emerald.

Nest description, nest survival, and habitat use of three resident hummingbird species in western Mexico

Nesting is a particularly sensitive period during which birds are highly vulnerable to predation, parasitism, and other natural events resulting in high mortality rates. Some factors can increase nesting success, such as habitat selection. In general, only female hummingbirds build nests, incubate eggs, and provide nestling care until chicks can feed independently. The purpose of our study was to describe nests (shape, size, and construction materials), nest survival, and habitat use of 3 resident hummingbirds in western Mexico: Cinnamon Hummingbird (Amazilia rutila), Golden-crowned Emerald (Cynanthus auriceps; a Mexican endemic), and Broad-billed Hummingbird (C. latirostris). In all 3 species, the nest is an open cup built with plant material and bound together with spider web. All 3 species used the same materials (silk cotton, wood, and grass) for nest construction. However, Cinnamon Hummingbird was the only one that used lichens at its outer surface, whereas Broad-billed Hummingbird used only seeds. We did not find interspecific differences among the materials used and their quantities. A low nest survival (26%) can be explained by the high rate of predation but also by the occurrence of natural events such as hurricanes. All 3 species showed preference for nesting in semi-deciduous forests but chose different nest placement sites that differed in (1) nest height, (2) the height of trees or shrubs where nests were built, and (3) the diameter of the supporting branch within a shrub or tree. Other factors, such as distance to the nearest stream, and distance to nesting-branch tip or trunk, did not differ among species.

DNA metabarcoding reveals broadly overlapping diets in three sympatric North American hummingbirds

ABSTRACT Hummingbirds, a highly diverse avian family, are specialized vertebrate pollinators that feed upon carbohydrate-rich nectar to fuel their fast metabolism while consuming invertebrates to obtain protein. Previous work has found that morphologically diverse hummingbird communities exhibit higher diet specialization on floral resources than morphologically similar hummingbird communities. Due to the difficulties of studying avian diets, we have little understanding whether hummingbirds show similar patterns with their invertebrate prey. Here, we use DNA metabarcoding to analyze floral and invertebrate diets of 3 species of sympatric North American hummingbirds. We collected fecal samples from 89 Anna’s (Calypte anna), 39 Black-chinned (Archilochus alexandri), and 29 Calliope (Selasphorus calliope) hummingbirds in urban and rural localities as well as across an elevational gradient from sea level to 2,500 meters above sea level in California, USA. We found hummingbirds showed high dietary overlap in both invertebrate and plant resources, with few invertebrate and plant families common to most individuals and many families found in only a few individuals. Chironomidae was the most common invertebrate family across all species, and Rosaceae and Orobanchaceae were the most common plant families. Anna’s Hummingbirds had significantly higher invertebrate diet diversity than Black-chinned Hummingbirds when found at the same sites, but we found no difference in plant diet diversity among any of the 3 species. Hummingbirds in urban sites had higher plant diet diversity than in rural sites, but we found no effect of elevation on dietary richness. Our study shows how DNA metabarcoding can be used to non-invasively investigate previously unknown life-histories of well-studied birds, lending insight to community structure, function, and evolution.

True grit: ingestion of small stone particles by hummingbirds in West Mexico

BackgroundGrit is used by birds mainly for grinding hard food items but can also serve a nutritional role as a source of minerals. Ingestion of grit by birds has been documented primarily in species that feed on seeds and invertebrates. Although feeding mainly on nectar and small arthropods, hummingbirds also ingest grit, but why they do so is unclear. We quantified the number of grit particles in the stomachs of six species of hummingbirds during an annual cycle in a seasonal ecosystem of West Mexico.MethodsWe compared the number of grit particles in the stomachs of different hummingbird species (Mexican Violetear Colibri thalassinus, Amethyst-throated Mountaingem Lampornis amethystinus, White-eared Hummingbird Basilinna leucotis, Rivoli’s Hummingbird Eugenes fulgens, Broad-tailed Hummingbird Selasphorus platycercus, and Rufous Hummingbird S. rufus), and between sex and age categories during the different seasons of a year. To determine if grit was used to grind ingested arthropods, we examined the relationships between the number of grit particles, the biomass of arthropods ingested, and their chitin content.ResultsAlthough species did not differ in the number of grit particles in their stomachs, we found that grit was mostly ingested by female individuals, with only one male of one species (Mexican Violetear) presenting grit in its stomach. We also found that female hummingbirds had grit in their stomachs during the rainy and the cold-dry season (June–February) but not during the warm-dry season (March–May). Our analyses revealed no relationship between the number of grit particles and the amount of ingested arthropods and arthropod chitin content. However, high grit consumption was related to wasp ingestion on Mexican Violetears.ConclusionsOur results indicate that grit is used mainly by female hummingbirds. The seasonal variation in the ingestion of grit by female individuals suggests that it can be used to meet mineral requirements related to breeding; however, this topic needs further exploration. Additionally, the use of grit was proportionally higher in juvenile individuals, suggesting it is used for grinding arthropods during a period of fast development.

A second decade of overwintering hummingbirds in Florida and Alabama

For a second decade, from November 2008 to March 2018, we examined the species diversity, return rate, longevity, and migration routes of hummingbirds overwintering in southern Alabama and the panhandle, northern peninsula, and central peninsula of Florida. We captured and banded 11 species of hummingbirds (n= 1,870 individuals), including 931 Rufous Hummingbirds (Selasphorus rufus; 49%), 583 Ruby-throated Hummingbirds (Archilochus colubris; 31%), 219 Black-chinned Hummingbirds (A. alexandri; 12%), 49 Buff-bellied Hummingbirds (Amazilia yucatanensis), 49 Calliope Hummingbirds (S. calliope), 19 Allen's Hummingbirds (S. sasin), 11 Broad-tailed Hummingbirds (S. platycercus), 6 Broad-billed Hummingbirds (Cynanthus latriostris), 1 Anna's Hummingbird (Calypte anna), 1 Costa's Hummingbird (Calypte costae), and 1 White-eared Hummingbird (Hylocharis leucotis). Site fidelity was high, with 299 hummingbirds of 5 species returning at least once. Two Rufous Hummingbirds migrated to our study area in the autumn from the West (Oklahoma and Texas). One Ruby-throated Hummingbird banded in Lakeland, Florida, was recovered in Utopia, New Brunswick, Canada, suggesting the overwintering Ruby-throated Hummingbirds in our study area are migratory and not sedentary.

On the nests, eggs, and reproductive evidence of Tyrian Metaltail (Metallura tyrianthina) and Glowing Puffleg (Eriocnemis vestita) in the northeastern Colombian Andes

The reproductive biology of tropical hummingbirds has been documented and studied in only a small fraction of species relative to the great diversity of this group. Little has been written about breeding biology of hummingbirds at the Northern Andes Eastern Cordillera in Colombia. We present detailed information on the dates, nesting locations, construction materials, measurements of nests and eggs, and gonad development of adult specimens to augment the scant reproductive data available of 2 widely distributed highland hummingbirds, the Tyrian Metaltail (Metallura tyrianthina) and the Glowing Puffleg (Eriocnemis vestita). These data were obtained during multi-taxa collection expeditions in the high-elevation region of the Department of Boyacá, Colombia. We found 2 Tyrian Metaltail nests in February and May, and adults with enlarged gonads in August. The single Glowing Puffleg nest was found in October, adults with enlarged gonads in May and October, and a chick mortality event (possibly due to frost) in November. Nesting sites for both species were in banks where they built 2-layered cup nests. Although nest locations and construction materials were similar to what has been reported before for hummingbirds in these genera, we identified the plants of these nests' microhabitats, as well as the families and genera of liverworts, mosses, and others used as nest construction materials. The evidence of active nests and enlarged gonads of specimens collected in this study, together with observations made by previous authors, suggest that these 2 hummingbird species breed throughout most of the year at the northeastern Andes. Our data contributes to the understanding of the reproductive biology of these hummingbirds in this region.

LOW PREVALENCE OF HAEMOSPORIDIANS IN BLOOD AND TISSUE SAMPLES FROM HUMMINGBIRDS.

Hummingbirds are vital members of terrestrial ecosystems, and because of their high metabolic requirements, they serve as indicators of ecosystem health. Monitoring the parasitic infections of hummingbirds is thus especially important. Haemosporidians, a widespread group of avian blood parasites, are known to infect hummingbirds, but little is known about the prevalence and diversity of these parasites in hummingbirds. The prevalence of haemosporidians in several hummingbird species was examined and we compared 4 different tissue types in detecting parasites by polymerase chain reaction (PCR). Blood samples from 339 individuals of 3 different hummingbird species were tested, and 4 individuals were found positive for haemosporidian infection, a prevalence of 1.2%. Hummingbird carcasses (n = 70) from 5 different hummingbird species were also sampled to assess differences in detection success of haemosporidians in heart, kidney, liver, and pectoral muscle tissue samples. Detection success was similar among tissue types, with haemosporidian prevalence of 9.96% in heart tissue, 9.52% in kidney tissue, 10.76% in liver tissue, and 11.76% in pectoral muscle tissue. All tissue samples positive for haemosporidian infection were from the Black-chinned Hummingbird (Archilochus alexandri). Possible reasons for low prevalence of these blood parasites could include low susceptibility to insect vectors or parasite incompatibility in these hummingbirds.

Key plant species to restore plant–hummingbird pollinator communities in the southern Andes of Ecuador

The planning and implementation of restoration in the Tropical Andes have yet to incorporate functional attributes of ecosystems such as pollination. Mutualistic network approaches can be especially useful for this purpose. For example, within networks of hummingbirds and their pollinated plants, most interactions occur on a small number of plant species that are key to conserve and recover pollination functions. To identify such species, centrality metrics derived from network analysis are readily available and can be easily applied. Our study was conducted in the southern Andes of Ecuador in four vegetation types: old‐growth forest, secondary forest, hedgerows, and montane shrub. On each vegetation type, we surveyed hummingbird visitation to plants and constructed plant–hummingbird interaction networks. We calculated a centrality index for each plant species and used this index to describe the individual role of species as either key or peripheral. We also explored how different functional traits of plants, including flower abundance, morphology, and nectar characteristics, were associated with the variation in this index. We found a total of 123 unique pairwise interactions between 44 plant and 15 hummingbird species. Within each vegetation type, we identified 4–11 key plant species. A shrubby life form and abundant flowers were the main traits associated with the key role of species. This study shows a robust protocol to select plant assemblages for the recovery of plant–hummingbird communities.

PREFORMATIVE MOLT EXTENT AND AGING AND SEXING CRITERIA FOR EIGHT HUMMINGBIRD SPECIES IN SOUTHEASTERN PERU

Little attention has been paid to molt and age criteria in hummingbirds despite the importance of molt and age to numerous behavioral and ecological questions. We examined age-based molt patterns and bill corrugations in eight species of lowland Amazonian hummingbirds. Molt strategies and rates of bill smoothing were similar to those of more well-studied North American species, with all species showing partial preformative molts (replacing only body feathers and some wing coverts and retaining all remiges and rectrices), and bill corrugations reducing to less than 10% of bill length in all species during the first annual cycle. Several species showed evidence of delayed maturation in males in regard to plumage characteristics or bill coloration.

First description of the nest and juveniles of the Coppery Metaltail (Metallura theresiae), with comments on hummingbird nestling obesity

I provide the first description of the nest and juveniles of the Coppery Metaltail (Metallura theresiae), a hummingbird endemic to Peru. The locality of Unchog, in the elfin forest of the Carpish mountains in Huánuco, is where I found this species nesting. My descriptions are based on 4 nests found on different occasions (April 2013, January 2014, and Jul–Aug 2014). Coppery Metaltail used mainly moss, lichen, lycopodium, and twigs as materials to build their nests. I found 3 nest locations: a tree branch, creek banks, and an abandoned hut. The mean internal diameter of nests was 34.45 mm long by 42.52 mm wide (n = 4). I only measured the depth of 3 of them (mean = 33.83 mm). Metaltail eggs were white and had a mean of 12.93 by 8.3 mm (n = 2). Fledglings (n = 2) were observed in July and one of them reached up to 144% the mass of an adult. I comment on other cases of nestling obesity for different species of hummingbirds. The Coppery Metaltail selects different substrates for nesting and might reproduce throughout the year.