Calliope Hummingbird Research Articles

Sampling affects population genetic inference: A case study of the Allen's (Selasphorus sasin) and rufous hummingbird (Selasphorus rufus).

Gene flow can affect evolutionary inference when species are undersampled. Here, we evaluate the effects of gene flow and geographic sampling on demographic inference of 2 hummingbirds that hybridize, Allen's hummingbird (Selasphorus sasin) and rufous hummingbird (Selasphorus rufus). Using whole-genome data and extensive geographic sampling, we find widespread connectivity, with introgression far beyond the Allen's × rufous hybrid zone, although the Z chromosome resists introgression beyond the hybrid zone. We test alternative hypotheses of speciation history of Allen's, rufous, and Calliope (S. calliope) hummingbird and find that rufous hummingbird is the sister taxon to Allen's hummingbird, and Calliope hummingbird is the outgroup. A model treating the 2 subspecies of Allen's hummingbird as a single panmictic population fit observed genetic data better than models treating the subspecies as distinct populations, in contrast to morphological and behavioral differences and analyses of spatial population structure. With additional sampling, our study builds upon recent studies that came to conflicting conclusions regarding the evolutionary histories of these 2 species. Our results stress the importance of thorough geographic sampling when assessing demographic history in the presence of gene flow.

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.

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.

Determination of neonicotinoids and butenolide residues in avian and insect pollinators and their ambient environment in Western Canada (2017, 2018)

To examine the spatial, and temporal variation and potential sources of pesticide concentrations, primarily neonicotinoid insecticides, in hummingbirds in western Canada, we sampled their cloacal fluid from sites in British Columbia and Saskatchewan, Canada in 2017–2018. At a sub-sample of those sites, we also measured pesticides in honey bee (Apis mellifera) nectar, water, and sediment. We collected cloacal fluid from 5 species of hummingbirds (n = 26 sites) in British Columbia (BC) and Saskatchewan, Canada, and nectar from honey bee hives (n = 4 sites), water and sediment (n = 18 sites) in the Fraser Valley, BC. Among those, multiple types of samples were collected at 6 sites. We report the first measurement of flupyradifurone, a relatively new butenolide insecticide, in wildlife which was detected at 4.58 ng/mL in hummingbird cloacal fluid and 2.18 ng/g in honey bee nectar. We also detected three other neonicotinoids (imidacloprid, clothianidin, acetamiprid) and one metabolite desnitro-imidacloprid, and MGK264, a pesticide synergist, in our samples. Among 49 samples of cloacal fluid from rufous (Selasphorus rufus), Anna's (Calypte anna), calliope (Selasphorus calliope) black-chinned (Archilocus alexandri) and ruby-throated hummingbirds (Archilocus colubris), 26.5% (n = 13) contained neonicotinoids. Maximum pesticide concentrations in hummingbirds, water and sediment were found in samples collected in the Fraser Valley, BC within 0.5 km of conventionally sprayed blueberry fields (CSBF) but highest levels in honey bee nectar were detected at a site 1.5 km from a CSBF. Imidacloprid in honey bee nectar at one site exceeded concentrations (>1 ng/g) that can sublethally affect worker bee foraging efficiency. In water, imidacloprid concentrations at another site exceeded Canadian guidelines (230 ng/mL) for the protection of aquatic invertebrates.

Evidence of linked selection on the Z chromosome of hybridizing hummingbirds.

Levels of genetic differentiation vary widely along the genomes of recently diverged species. What processes cause this variation? Here, I analyze geographic population structure and genome-wide patterns of variation in the Rufous, Allen's, and Calliope Hummingbirds (Selasphorus rufus/Selasphorus sasin/Selasphorus calliope) and assess evidence that linked selection on the Z chromosome drives patterns of genetic differentiation in a pair of hybridizing species. Demographic models, introgression tests, and genotype clustering analyses support a reticulate evolutionary history consistent with divergence during the late Pleistocene followed by gene flow across migrant Rufous and Allen's Hummingbirds during the Holocene. Relative genetic differentiation ( ) is elevated, and within-population diversity (π) is depressed on the Z chromosome in all interspecific comparisons. The ratio of Z to autosomal within-population diversity is much lower than that expected from population size effects alone, and Tajima's D is depressed on the Z chromosome in S. rufus and S. calliope. These results suggest that conserved structural features of the genome play a prominent role in shaping genetic differentiation through the early stages of speciation in northern Selasphorus hummingbirds, and that the Z chromosome is a likely site of genes underlying behavioral and morphological variation in thegroup.

Hovering in the heat: effects of environmental temperature on heat regulation in foraging hummingbirds.

At high temperature (greater than 40°C) endotherms experience reduced passive heat dissipation (radiation, conduction and convection) and increased reliance on evaporative heat loss. High temperatures challenge flying birds due to heat produced by wing muscles. Hummingbirds depend on flight for foraging, yet inhabit hot regions. We used infrared thermography to explore how lower passive heat dissipation during flight impacts body-heat management in broad-billed (Cynanthus latirostris, 3.0 g), black-chinned (Archilochus alexandri, 3.0 g), Rivoli's (Eugenes fulgens, 7.5 g) and blue-throated (Lampornis clemenciae, 8.0 g) hummingbirds in southeastern Arizona and calliope hummingbirds (Selasphorus calliope, 2.6 g) in Montana. Thermal gradients driving passive heat dissipation through eye, shoulder and feet dissipation areas are eliminated between 36 and 40°C. Thermal gradients persisted at higher temperatures in smaller species, possibly allowing them to inhabit warmer sites. All species experienced extended daytime periods lacking thermal gradients. Broad-billed hummingbirds lacking thermal gradients regulated the mean total-body surface temperature at approximately 38°C, suggesting behavioural thermoregulation. Blue-throated hummingbirds were inactive when lacking passive heat dissipation and hence might have the lowest temperature tolerance of the four species. Use of thermal refugia permitted hummingbirds to tolerate higher temperatures, but climate change could eliminate refugia, forcing distributional shifts in hummingbird populations.

Three-dimensional simulation for fast forward flight of a calliope hummingbird

We present a computational study of flapping-wing aerodynamics of a calliope hummingbird (Selasphorus calliope) during fast forward flight. Three-dimensional wing kinematics were incorporated into the model by extracting time-dependent wing position from high-speed videos of the bird flying in a wind tunnel at 8.3 m s−1. The advance ratio, i.e. the ratio between flight speed and average wingtip speed, is around one. An immersed-boundary method was used to simulate flow around the wings and bird body. The result shows that both downstroke and upstroke in a wingbeat cycle produce significant thrust for the bird to overcome drag on the body, and such thrust production comes at price of negative lift induced during upstroke. This feature might be shared with bats, while being distinct from insects and other birds, including closely related swifts.

Three-dimensional simulation for fast forward flight of a calliope hummingbird

Three-dimensional simulation for fast forward flight of a calliope hummingbird

Heat dissipation during hovering and forward flight in hummingbirds.

Flying animals generate large amounts of heat, which must be dissipated to avoid overheating. In birds, heat dissipation is complicated by feathers, which cover most body surfaces and retard heat loss. To understand how birds manage heat budgets during flight, it is critical to know how heat moves from the skin to the external environment. Hummingbirds are instructive because they fly at speeds from 0 to more than 12 m s−1, during which they transit from radiative to convective heat loss. We used infrared thermography and particle image velocimetry to test the effects of flight speed on heat loss from specific body regions in flying calliope hummingbirds (Selasphorus calliope). We measured heat flux in a carcass with and without plumage to test the effectiveness of the insulation layer. In flying hummingbirds, the highest thermal gradients occurred in key heat dissipation areas (HDAs) around the eyes, axial region and feet. Eye and axial surface temperatures were 8°C or more above air temperature, and remained relatively constant across speeds suggesting physiological regulation of skin surface temperature. During hovering, birds dangled their feet, which enhanced radiative heat loss. In addition, during hovering, near-body induced airflows from the wings were low except around the feet (approx. 2.5 m s−1), which probably enhanced convective heat loss. Axial HDA and maximum surface temperature exhibited a shallow U-shaped pattern across speeds, revealing a localized relationship with power production in flight in the HDA closest to the primary flight muscles. We conclude that hummingbirds actively alter routes of heat dissipation as a function of flight speed.

The value of information to foraging Calliope Hummingbirds

Foragers may vary in their memories regarding the location and expected quality of resources. This difference in memory often corresponds to whether a forager either simultaneously encounters or sequentially encounters its food. To test for the effects of information, I examined the foraging patterns of calliope hummingbirds consuming different concentrations of sucrose that were marked or unmarked. I also examined the effects of uncertainty associated with alternative food sources by altering the mean and variance in sucrose concentration in marked and unmarked feeders. I found that hummingbirds feeding from marked feeders were more selective when Rich (= high sucrose items) and Poor (= low sucrose items) resources occurred in distinct, pure patches as opposed to patches containing a mixture of Rich and Poor items. When resource types were intermixed, hummingbirds feeding on marked feeders were selective as a continuous function, and foragers feeding on unmarked feeders were selective as a nonlinear function, of the relative values of different resources. Only one prediction of foraging on marked feeders was not supported, namely when Poor-quality items were located near Rich items, calliope hummingbirds did not show a greater preference for Poor items than when Poor items were far from Rich items. This last-mentioned result may indicate that the travel distance between Rich and Poor items was too short to warrant differentiating between Rich and Poor feeders. Hummingbirds preferred marked feeders when the mean sucrose concentration was greater or equal to that of unmarked feeders, but preferred unmarked feeders when mean sucrose concentration was lower in marked feeders. There was a significant positive correlation between visits to marked feeders and the coefficient of variation of unmarked feeders. These results indicate that when all things are equal, calliope hummingbirds prefer to forage where most information is available about resource quality.

Citizen‐science data provides new insight into annual and seasonal variation in migration patterns

Current rates of global environmental and climate change pose potential challenges for migratory species that must cope with or adapt to new conditions and different rates of change across broad spatial scales throughout their annual life cycle. North American migratory hummingbirds may be especially sensitive to changes in environment and climate due to their extremely small body size, high metabolic rates, and dependence on nectar as a main resource. We used occurrence information from the eBird citizen‐science database to track migratory movements of five North American hummingbird species (Archilochus alexandri, A. colubris, Selasphorus calliope, S. platycercus, and S. rufus) across 6 years (2008–2013) at a daily temporal resolution to describe annual and seasonal variation in migration patterns. Our findings suggest that the timing of the onset of spring migration generally varies less than the arrival on the wintering grounds. Species follow similar routes across years, but exhibit more variation in daily longitude than latitude. Long distance migrants generally had less annual variation in geographic location and timing than shorter distance migrants. Our study is among the first to examine variation in migration routes and timing for hummingbirds, but more work is needed to understand the capacity of these species to respond to different rates of environmental change along their migratory routes.

Harmonic hopping, and both punctuated and gradual evolution of acoustic characters in Selasphorus hummingbird tail-feathers.

Models of character evolution often assume a single mode of evolutionary change, such as continuous, or discrete. Here I provide an example in which a character exhibits both types of change. Hummingbirds in the genus Selasphorus produce sound with fluttering tail-feathers during courtship. The ancestral character state within Selasphorus is production of sound with an inner tail-feather, R2, in which the sound usually evolves gradually. Calliope and Allen's Hummingbirds have evolved autapomorphic acoustic mechanisms that involve feather-feather interactions. I develop a source-filter model of these interactions. The ‘source’ comprises feather(s) that are both necessary and sufficient for sound production, and are aerodynamically coupled to neighboring feathers, which act as filters. Filters are unnecessary or insufficient for sound production, but may evolve to become sources. Allen's Hummingbird has evolved to produce sound with two sources, one with feather R3, another frequency-modulated sound with R4, and their interaction frequencies. Allen's R2 retains the ancestral character state, a ∼1 kHz “ghost” fundamental frequency masked by R3, which is revealed when R3 is experimentally removed. In the ancestor to Allen's Hummingbird, the dominant frequency has ‘hopped’ to the second harmonic without passing through intermediate frequencies. This demonstrates that although the fundamental frequency of a communication sound may usually evolve gradually, occasional jumps from one character state to another can occur in a discrete fashion. Accordingly, mapping acoustic characters on a phylogeny may produce misleading results if the physical mechanism of production is not known.

Time Budgets of Male Calliope Hummingbirds on a Dispersed Lek

Several authors have suggested that male Calliope Hummingbirds (Selasphorus calliope) perform their dive and shuttle displays on “dispersed leks” where the dramatic aerial displays of several individuals can be seen or heard from a single location. To expand on the limited information available on breeding territorial behavior, I provide detailed time budget data from 3 years of observation of males in a 20-year-old seed-tree cut in Montana. Males spent the vast majority of their time (76%, on average) perched on dead willow branches that extended upward to 4–5 m in height, and an average of 90% of perch time was spent at no more than three perch sites. Most of the rest of the males' time (15%, on average) was spent off territory, where they conducted a good portion of their feeding. About 6% of a male's time was spent performing energetically demanding dive and shuttle displays, which were directed primarily toward females, but also toward other bird species perched within the male's territory. Displays directed toward females were sometimes followed by copulation while she was perched. This is only the second geographic location where male Calliope Hummingbirds are reported to have congregated in what appears to be a dispersed lek. We still know little about how common the clustering of breeding territories is, whether such clustering is limited to early successional habitat, and whether relatively few males obtain most of the copulations in such clusters, as would be expected in a classic lek breeding system.

Simultaneous Multiple Nests of Calliope Hummingbird and Rufous Hummingbird

We report the first cases of simultaneous double brooding known for Calliope Hummingbird (Stellula calliope) and Rufous Hummingbird (Selasphorus rufus) from observations of two females in Montana. Each female laid two eggs and started incubating while feeding large young in a nearby nest, and each successfully fledged young from both nesting attempts. Simultaneous multiple nests have been documented for five other hummingbird species that breed north of Mexico, suggesting the behavior is widespread in the family outside the tropics. Factors that might allow rapid renesting in temperate species include young that begin to feed themselves within a week after fledging, and longer day length that allows more time for females to forage than would be available in the tropics.

Wing, tail, and vocal contributions to the complex acoustic signals of courting Calliope hummingbirds

Abstract Multi-component signals contain multiple signal parts expressed in the same physical modality. One way to identify individual components is if they are produced by different physical mechanisms. Here, I studied the mechanisms generating acoustic signals in the courtship displays of the Calliope hummingbird Stellula calliope. Display dives consisted of three synchronized sound elements, a high-frequency tone (hft), a low frequency tone (lft), and atonal sound pulses (asp), which were then followed by a frequency-modulated fall. Manipulating any of the rectrices (tail-feathers) of wild males impaired production of the lft and asp but not the hft or fall, which are apparently vocal. I tested the sound production capabilities of the rectrices in a wind tunnel. Single rectrices could generate the lft but not the asp, whereas multiple rectrices tested together produced sounds similar to the asp when they fluttered and collided with their neighbors percussively, representing a previously unknown mechanism of sound production. During the shuttle display, a trill is generated by the wings during pulses in which the wingbeat frequency is elevated to 95 Hz, 40% higher than the typical hovering wingbeat frequency. The Calliope hummingbird courtship displays include sounds produced by three independent mechanisms, and thus include a minimum of three acoustic signal components. These acoustic mechanisms have different constraints and thus potentially contain different messages. Producing multiple acoustic signals via multiple mechanisms may be a way to escape the constraints present in any single mechanism.

Noteworthy bird records from central Sinaloa, Mexico

Reportamos registros meritorios de Anous stolidus, Stellula calliope, Sphyrapicus varius, Myiopagis viridicata, Dendroica pensylvanica y Pheucticus ludovicianus del centro de Sinaloa. La mayoría de las aves fueron capturadas con redes de niebla. Aunque los registros parecen ser de individuos vagabundos, podría ser que la severa modificación del hábitat de la zona costera de Sinaloa esté facilitando la dispersión de algunas especies. La ausencia de registros previos de estas especies parece estar más relacionada con un bajo esfuerzo de observación que con incrementos en la distribución geográfica de las especies.

ON THE ROLE OF WING SOUNDS IN HUMMINGBIRD COMMUNICATION

The function of nonvocal sounds in avian communication has rarely been investigated. I used playback of natural and digitally altered wing sounds from both sexes of Calliope Hummingbird (Stellula calliope) and Rufous Hummingbird (Selasphorus rufus) to test whether these stimuli altered their behavior. Stimuli played from behind target birds at artificial feeders were used to study responses that characterized the level of threat associated with each wing-sound stimulus. I classified the behaviors into one of five response categories and analyzed the data using log-linear (Poisson) models. I found that the wing-trill signal of males strongly altered the behavior of both conspecific and heterospecific recipients. Females responded more strongly than males to male stimuli, and stronger responses were elicited by male Rufous Hummingbird than by male Calliope Hummingbird stimuli. I used digitally altered wing-sound stimuli to investigate further which sound components are used in communication. The results, in conjunction with previous research that has shown fitness benefits to the sender of the signal, lead me to conclude that male wing trill is an important component of hummingbird communication. Female wing sounds elicited stronger responses than control sounds, but the base wing-hum sound itself appears to be a simple by-product of flight rather than a communication signal. These results of the first playback study using nonvocal avian sounds suggest that further research to identify which nonvocal sounds are communication signals is needed.

IN MEMORIAM: WILLIAM ALEXANDER CALDER III, 1934–2002

The life of William Alexander Calder III was ended abruptly on 23 April 2002, by acute leukemia. The disease was diagnosed only a short time before his death and progressed rapidly. Bill Calder's entire life was fast-paced; his mind and body never seemed to stop in his efforts to reach mountaintops, to solve physiological questions, or to offer solutions to environmental problems for newspaper readers or rural residents of remote parts of Mexico. Bill was born in Cambridge, Massachusetts, on 2 September 1934. At age 16, participation in field trips sponsored by the Atlanta Audubon Society led to an interest in bird watching. He acquired a distaste for collecting when a professor shot a Great Blue Heron but failed to prepare the specimen. After two years at Emory University and summers spent as a Forest Service smoke-jumper in Montana, he completed his BS degree in zoology from the University of Georgia in 1955. Enlisting in the U.S. Coast Guard, he became a pilot of twin-engined seaplanes, search and rescue operations and fish and wildlife patrols in Florida, Texas, and Washington. Graduate school took him to Washington State University where he studied Zebra Finch metabolism for an MS thesis (1963) under the guidance of James R. King, and then to Duke for a Ph.D. dissertation (1966) on roadrunner metabolism with Knut Schmidt-Nielsen. During that time, two summers were spent as a seasonal naturalist at Grand Teton National Park, where his interest in hummingbirds was initiated by a Calliope Hummingbird nest, and one summer as a rangernaturalist at Glacier National Park. After two years teaching at Virginia Polytechnic Institute, he moved to the University of Arizona at Tucson in 1969, becoming a professor in the Department of Ecology and Evolutionary Biology in 1974. He joined the AOU in 1961, becoming an Elective Member in 1974, and a Fellow in 1988. Bill's earlier research publications concerned mainly water balance, respiration, and energetics of birds, but he published two papers on temperature relationships of the water shrew. In 1971 he spent the first of many summers at the Rocky Mountain Biological Laboratory (RMBL) in Gothic, Colorado. There he investigated physiological problems associated with small size, especially of hummingbirds. For the rest of his life, most of his research focused on hummingbirds; it resulted in many papers on their physiology, ecology, and behavior. A significant departure was a sabbatical in New Zealand in 1976-1977, where he studied kiwi physiology. His interest in tiny mammals, tiny birds, and big eggs (as in the kiwi) led him to question many established ideas about the relationship between size and function; he wrote Size, Function, and Life History (1984, Harvard University Press). He contributed chapters to a number of books, most on hummingbirds, matters of size, and conservation issues. Personal research with subsequent publication was not Bill's only goal; he was a dedicated teacher at both the graduate and undergraduate levels. He wanted students to question what they saw and read and to learn to derive their own answers. He was irreverent of established rule and used provocative questions daily in his classroom. He transmitted the joy of doing science; his own work proved it could be fun. Theories were never lacking in his discussions; he could always offer a theory about anything. Many ideas were not productive, but others led to fruitful research. The University of Arizona College of Science honored him in 2002 with its Career Mentoring Award, in recognition of a lifetime of excellence in teaching. He left a compelling model on how to live and how to do science, described by one of his colleagues as equal parts of humor, keen observation, hard work, and absolute honesty. Bill's love of the outdoors was a compulsion; he liked nothing better than to climb the nearest high mountain. At RMBL, he often invited new students or colleagues to talk with him, but that involved bushwhacking to a nearby 13,000 ft (3,950 m) peak! His physiological ecology course was dubbed Backpacking 101. With his wife Lorene, he started graduate student seminars at which they would serve peppermint tea prepared on a wood burning stove and served in specimen jars. He was a regular participant in the 4th of July footrace, an eight mile (13 km) ordeal between Gothic and

Size and Abundance: Breeding Population Density of the Calliope Hummingbird

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Display Behavior of Male Calliope Hummingbirds during the Breeding Season

Etude descriptive des comportements de defense du territoire des mâles de Stellula calliope lors de la periode de reproduction. De plus, la sequence complete de l'accouplement est decrite. Les differences entre le comportement de cour de Stellula calliope est de calypte anna, deux especes de Colibri, sont discutees