Elf Owl Research Articles

A Tale of Two Molecules: The Underprediction of CO2 and Overprediction of PH3 in Late T and Y Dwarf Atmospheric Models

The sensitivity and spectral coverage of JWST are enabling us to test our assumptions of ultracool dwarf atmospheric chemistry, especially with regards to the abundances of phosphine (PH3) and carbon dioxide (CO2). In this paper, we use Near Infrared Spectrograph PRISM spectra (∼0.8−5.5 μm, R ∼ 100) of four late T and Y dwarfs to show that standard substellar atmosphere models have difficulty replicating the 4.1−4.4 μm wavelength range, as they predict an overabundance of phosphine and an underabundance of carbon dioxide. To help quantify this discrepancy, we generate a grid of models using PICASO, based on the Elf Owl chemical and temperature profiles, where we include the abundances of these two molecules as parameters. The fits to these PICASO models show a consistent preference for orders-of-magnitude higher CO2 abundances and a reduction in PH3 abundance as compared to the nominal models. This tendency means that the claimed phosphine detection in UNCOVER−BD−3 could instead be explained by a CO2 abundance in excess of standard atmospheric model predictions; however, the signal-to-noise ratio of the spectrum is not high enough to discriminate between these cases. We discuss atmospheric mechanisms that could explain the observed underabundance of PH3 and overabundance of CO2, including a vertical eddy diffusion coefficient (K zz) that varies with altitude, incorrect chemical pathways, or elements condensing out in forms such as NH4H2PO4. However, our favored explanation for the required CO2 enhancement is that the quench approximation does not accurately predict the CO2 abundance, as CO2 remains in chemical equilibrium with CO after CO quenches.

The Sonora Substellar Atmosphere Models. IV. Elf Owl: Atmospheric Mixing and Chemical Disequilibrium with Varying Metallicity and C/O Ratios

Disequilibrium chemistry due to vertical mixing in the atmospheres of many brown dwarfs and giant exoplanets is well established. Atmosphere models for these objects typically parameterize mixing with the highly uncertain K zz diffusion parameter. The role of mixing in altering the abundances of C-N-O-bearing molecules has mostly been explored for atmospheres with a solar composition. However, atmospheric metallicity and the C/O ratio also impact atmospheric chemistry. Therefore, we present the Sonora Elf Owl grid of self-consistent cloud-free 1D radiative-convective equilibrium model atmospheres for JWST observations, which includes a variation in K zz across several orders of magnitude and also encompasses subsolar to supersolar metallicities and C/O ratios. We find that the impact of K zz on the T(P) profile and spectra is a strong function of both T eff and metallicity. For metal-poor objects, K zz has large impacts on the atmosphere at significantly higher T eff than in metal-rich atmospheres, where the impact of K zz is seen to occur at lower T eff. We identify significant spectral degeneracies between varying K zz and metallicity in multiple wavelength windows, in particular, at 3–5 μm. We use the Sonora Elf Owl atmospheric grid to fit the observed spectra of a sample of nine early to late T-type objects from T eff = 550–1150 K. We find evidence for very inefficient vertical mixing in these objects, with inferred K zz values lying in the range between ∼101 and 104 cm2 s−1. Using self-consistent models, we find that this slow vertical mixing is due to the observations, which probe mixing in the deep detached radiative zone in these atmospheres.

Factors influencing detectability and responses of Elf Owls to playback of conspecific vocalizations

Factors influencing detectability and responses of Elf Owls to playback of conspecific vocalizations

Avian thermoregulation in the heat: metabolism, evaporative cooling and gular flutter in two small owls.

The thermoregulatory responses of owls to heat stress have been the subject of few studies. Although nocturnality buffers desert-dwelling owls from significant heat stress during activity, roost sites in tree and cactus cavities or in deep shade provide only limited refuge from high environmental temperatures during the day. We measured thermoregulatory responses to acute heat stress in two species of small owls, the elf owl (Micrathene whitneyi) and the western screech-owl (Megascops kennicottii), which occupy the Sonoran Desert of southwestern North America, an area of extreme heat and aridity. We exposed wild-caught birds to progressively increasing air temperatures (Ta) and measured resting metabolic rate (RMR), evaporative water loss (EWL), body temperature (Tb) and heat tolerance limits (HTL; the maximum Ta reached). Comparatively low RMR values were observed in both species, Tb approximated Ta at 40°C and mild hyperthermia occurred as Ta was increased toward the HTL. Elf owls and screech-owls reached HTLs of 48 and 52°C, respectively, and RMR increased to 1.5 and 1.9times thermoneutral values. Rates of EWL at the HTL allowed for the dissipation of 167-198% of metabolic heat production (MHP). Gular flutter was used as the primary means of evaporative heat dissipation and produced large increases in evaporative heat loss (44-100%), accompanied by only small increases (<5%) in RMR. These small, cavity-nesting owls have thermoregulatory capacities that are intermediate between those of the open-ground nesting nightjars and the passerines that occupy the same ecosystem.

Suspected Anaphylaxis to Leuprolide Acetate Depot in Two Elf Owls (Micrathene whitneyi)

Two adult female elf owls (Micrathene whitneyi) were treated with leuprolide acetate depot injections to prevent egg laying. The birds were treated for several years without complications. Several years into the treatment regimen, both birds died immediately after receiving an injection of leuprolide acetate. Remaining drug was analyzed, revealing 95.7% potency. We suspect that either an immediate Type 1 hypersensitivity reaction occurred or a contaminant was present, resulting in the fatalities of these elf owls. No reports of anaphylaxis to leuprolide acetate in birds were identified in the literature. Clinicians should be aware of the possibility of anaphylaxis when administering this medication to avian patients.

Species Richness, Relative Abundance, and Habitat Associations of Nocturnal Birds Along the Rio Grande in Southern Texas

Abstract The segment of the Rio Grande between International Falcon Reservoir and Del Rio, Texas (distance ca. 350 km), remains largely unexplored ornithologically. We surveyed nocturnal birds monthly during February–June 1998 at 19 stations along the Rio Grande (n = 6) and at upland stock ponds (n = 13) in Webb County, Texas. We conducted 10-min point counts (n = 89) after sunset and before moonset. Four species of owls and five species of nightjars were detected. Nightjars, as a group, were nearly five times more abundant (mean number/count = 2.63) than owls (mean number = 0.55). The most common owl, the great horned owl (Bubo virginianus), had a mean number of 0.25/point count. The mean for elf owls (Micrathene whitneyi) was 0.16/point count. The most common nightjars were the common poorwill (Phalaenoptilus nuttallii; 1.21/point count) and lesser nighthawk (Chordeiles acutipennis; 1.16/point count). Survey sites on the river supported more species (mean = 2.2) than did upland stock ponds (...

Owls of the United States and Canada: a complete guide to their biology and behavior

There is no group of birds more mysterious and fascinating than owls. The loudmouths of the raptor world, they peep, trill, toot, bark, growl, shriek, whistle, chittle, whoop, chuckle, boom, and buzz. Indeed, very few actually hoot. They have become the stuff of lore and legend-from the Roman myth that an owl foot could reveal secrets to the First Nations belief that an owl feather could give a newborn better night vision. But the truth about owls is much more exciting. In this gorgeous book, celebrated natural history writer and wildlife photographer Wayne Lynch reveals the secrets of this elusive species with stunning photographs, personal anecdotes, and accessible science. The photos alone are masterpieces. Unlike most published owl photos, which are portraits of birds in captivity, the vast majority of these were taken in the wild-a product of the author-photographer's incredible knowledge and patience. Lynch complements the photos with a wealth of facts about anatomy, habitat, diet, and family life. For each of the nineteen species that inhabit Canada and the United States, he provides a range map and a brief discussion of its distribution, population size, and status. Lynch debunks myths about owls' supernatural powers of sight and hearing, discusses courtship rituals, and offers personal tips for finding owls in the wild. From the great horned to the tiny elf owl, this amazing volume captures the beauty and mystery of these charismatic birds of prey.

Two New Late Pleistocene Avifaunas From New Mexico

Abstract We report two new late Pleistocene avifaunas from New Mexico, recovered from Sandia Cave during archaeological excavations by F. Hibben in the 1930s and the nearby Marmot Cave excavated in 2000. The fossil assemblage from Sandia Cave consists of at least 30 taxa, including seven extralimital and two extinct species, Coragyps occidentalis (extinct vulture) and Ectopistes migratorius (Passenger Pigeon). The avifauna from Marmot Cave is limited to eight taxa shared with Sandia Cave. Two new records of Gymnogyps californianus (California Condor) are reported from these sites, as well as new records of Lagopus sp. (ptarmigan), Aegolius funereus (Boreal Owl), and Micrathene whitneyi (Elf Owl) from New Mexico. Two new radiocarbon dates on fossil G. californianus from Sandia and Marmot cave are reported at 10 795 ± 50 and 25 090 ± 220 14C years before present (B.P.), respectively. These collections provide further evidence for mixed avian communities in New Mexico during the late Pleistocene and are similar to other cave avifaunas of comparable age from the Great Basin and Rocky Mountain regions. The birds from Sandia Cave that are shared with other fossil avifaunas include species currently found in arctic tundra, boreal, and steppe habitats, as well as open, xeric communities. This collection provides additional evidence for widespread steppe-tundra, shrub, and subalpine forest environments at lower elevations of western North America during the late Pleistocene.

TWO NEW LATE PLEISTOCENE AVIFAUNAS FROM NEW MEXICO

Abstract We report two new late Pleistocene avifaunas from New Mexico, recovered from Sandia Cave during archaeological excavations by F. Hibben in the 1930s and the nearby Marmot Cave excavated in 2000. The fossil assemblage from Sandia Cave consists of at least 30 taxa, including seven extralimital and two extinct species, Coragyps occidentalis (extinct vulture) and Ectopistes migratorius (Passenger Pigeon). The avifauna from Marmot Cave is limited to eight taxa shared with Sandia Cave. Two new records of Gymnogyps californianus (California Condor) are reported from these sites, as well as new records of Lagopus sp. (ptarmigan), Aegolius funereus (Boreal Owl), and Micrathene whitneyi (Elf Owl) from New Mexico. Two new radiocarbon dates on fossil G. californianus from Sandia and Marmot cave are reported at 10 795 ± 50 and 25 090 ± 220 14C years before present (B.P.), respectively. These collections provide further evidence for mixed avian communities in New Mexico during the late Pleistocene and are simi...

NEST SITE SELECTION BY ELF OWLS IN THE SONORAN DESERT

Abstract Features of the nest cavity, nest tree, and surrounding vegetation have variously been shown to be important in nest site selection by cavity-nesting birds, yet few investigators have simultaneously considered these three habitat components. During 1995 and 1996 we considered each component in a study of nest site selection by Elf Owls (Micrathene whitneyi) in the Sonoran Desert. All Elf Owl nests (n = 68) were located in saguaros (Carnegiea gigantea) with a density of 0.032 nest saguaros/ha. At the scale of the nesting area, the number of cavities in a saguaro was the most important variable influencing whether it was selected for nesting; each additional cavity in a saguaro increased the odds it was selected by a factor of 4.4. Increasing the density of mature saguaros also increased the odds that an area was selected. At the scale of the nest saguaro, nest cavities were located in the main stem in greater proportion than their availability and were located higher above ground than random cavit...

RESPONSIVENESS OF ELF OWLS TO CONSPECIFIC AND GREAT HORNED OWL CALLS

A common assumption made when conducting broadcast surveys for owls is that vocalizations of larger owls reduce the responsiveness of smaller owls. We tested this assumption by comparing the responsiveness of Elf Owls (Micrathene whitneyi) exposed to the taped calls of conspecifics and to imitations of Great Horned Owls (Bubo virginianus). Elf Owls were more responsive to conspecific calls during courtship and incubation, but less responsive during the nestling stage, than they were to Great Horned Owl calls. This was because responsiveness to conspecific calls decreased through the nesting season, but responsiveness to Great Horned Owl calls was consistent throughout the nesting season. Singing Elf Owls switched from song to scold vocalizations more frequently after hearing a Great Horned Owl call (83.3%) than when hearing a conspecific call (33.3%). The responsiveness of Elf Owls to Great Horned Owl calls may benefit studies conducted throughout the breeding season.

Late Quaternary Plants and Vertebrates from Picacho Peak, Arizona

Eighty-two plant and 26 small vertebrate taxa were identified from four radiocarbon dated woodrat (Neotoma sp.) midden samples from a rock crevice at 655 m elevation on Picacho Peak, Pinal Co., Arizona. A late Wisconsin (11,100 to 13,170 YBP) pinyon-juniper-oak woodland dominated by Pinus monophylla (singleleaf pinyon) and Juniperus cf. osteosperma (Utah juniper) and J. erythrocarpa/monosperma (redberry/oneseed juniper) shifted to a more xeric juniper-oak woodland/chaparral in the early Holocene (9,420 to 10,280 YBP). Extralocal species that no longer live on Picacho Peak were 29.9% in the late Wisconsin and 20.1% in the early Holocene with the greatest changes in longlived trees, shrubs, and succulents. The biogeographic and taxonomic significance of Scaphiopus hammondi (western spadefoot) and the ecological adaptability of Phrynosoma platyrhinos (desert horned lizard), Micranthe whitneyi (elf owl), and Neotoma cf. albigula (white-throated woodrat) are discussed. All taxa in the vertebrate fauna are widespread in desertscrub and desert-grassland, still occur in the area, and enter woodlands only at the upper or northern edges of their ranges. The typical inhabitation of woodlands by these vertebrates and anomalous associations in the flora probably reflect the expansion of equable climates that now characterize ecotonal habitats during the late Wisconsin glacial. Analyses of plant remains preserved in ancient woodrat (Neotoma sp.) middens are providing excellent developmental sequences for local floras and vegetation for the last 20,000 to 40,000 years on rocky slopes in the southwestern United States and northern Mexico (Van Devender et al., 1987a). During the last glacial (the Wisconsin) period, woodlands expanded into the modern Sonoran Desert in southwestern Arizona and adjacent California (111* to 113*W). Pinyon-juniper-oak woodland dominated by Pinus monophylla (singleleaf pinyon) was at 600 to 1,555 m elevation with a xeric Juniperus californica (California juniper) woodland down to about 300 m, and Larrea divaricata (creosotebush) desertscrub at lower elevations along the Colorado River and around the head of the Gulf of California in Sonora and Baja California (Van Devender, 1990). Animal remains are much less common than plants in woodrat middens but provide insight into faunal responses to changing climate and vegetation (Van Devender and Mead, 1978; Van Devender et al., 1979; Mead and Phillips, 1981; Mead et al., 1983). Here we report the pla and vertebrate remains in woodrat middens from Picacho Peak, Arizona. MATERIALS AND METHODS-Picacho Peak was an isolated butte in Picacho Peak State Park rising from 550 m elevation at the base to 1,030 m at the top (Briscoe, 1967; Shafiquallah et al., 1976; Yeend, 1976). The nearest mountains of larger size were the Santa Catalina Mountains just north of Tucson (55 km SE) that rose to 2,790 m elevation. The lowest elevation near Picacho Peak was 520 m along the Santa Cruz River (3 km SW). The local climate was characterized by infrequent winter freezes, hot summers, and biseasonal rainfall from Pacific winter frontal storms and the subtropical summer monsoon. Mean temperatures for Eloy (15 km NW) at 475 m were 10.8*C for January and 32.3*C for July with extremes of 10.6*C and 47.2*C (Sellers and Hill, 1974). Precipitation was 215 mm/year with 40.6% falling from June to September. Picacho Peak was in the relatively well-watered Arizona Upland Subdivision of the northeastern Sonoran Desert (Shreve, 1964; Turner and Brown, 1982). The vegetation on rocky slopes and bajadas was dominated by Cercidium microphyllum (foothill paloverde), Olneya tesota (ironwood), and Carnegiea gigantea (saguaro) in This content downloaded from 207.46.13.149 on Mon, 03 Oct 2016 06:10:19 UTC All use subject to http://about.jstor.org/terms September 1991 Van Devender et al.-Late Quaternary plants and vertebrates 303

Nest Site Selection by Elf Owls in Saguaro National Monument, Arizona

Nest Site Selection by Elf Owls in Saguaro National Monument, Arizona

Northeastern Extension of the Breeding Range of the Elf Owl in New Mexico

Northeastern Extension of the Breeding Range of the Elf Owl in New Mexico

Exhibiting and breeding Elf owls: at Washington Zoo

International Zoo YearbookVolume 10, Issue 1 p. 33-36 Exhibiting and breeding Elf owls: at Washington Zoo KERRY A. MULLER, KERRY A. MULLER Zoologist, Division of Birds, National Zoological Park, Smithsonian Institution, Washington, DC, USASearch for more papers by this author KERRY A. MULLER, KERRY A. MULLER Zoologist, Division of Birds, National Zoological Park, Smithsonian Institution, Washington, DC, USASearch for more papers by this author First published: January 1970 https://doi.org/10.1111/j.1748-1090.1970.tb01265.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume10, Issue1January 1970Pages 33-36 RelatedInformation

Some Aspects of Temperature Relations in Small Owls

THE owls, Strigiformes, and goatsuckers, Ca.primulgiformes, are the only widespread groups of terrestrial birds in which most species are crepuscular or nocturnal. Members of these groups exhibit morphological modifications related to their modes of life, such as enlarged, specialized eyes and the asymmetrical ears of some owls. It is of interest to speculate on possible physiological modifications in metabolic rates and temperature regulation that can be correlated with nocturnal periods of activity. Birds active at night, when temperature is at its lowest, would possibly require less special augmentation of metabolic rate, as by shivering, than diurnal species. In addition they might have low rates of metabolism that would decrease energy requirements. Nocturnal species might be expected to be less tolerant of high ambient temperatures than diurnal ones that are active during the warmer parts of the daily cycle, and also, to be less capable of withstanding extreme elevations, of body temperature. Two species of the family Caprimulgidae, the Poor-will (Phalaenoptilus nuttallii) and the Common Nighthawk (Chordeiles minor), have been carefully studied and both do, indeed show unusually low rates of metabolism (Bartholomew et al., 1962; Lasiewski and Dawson, 1964). Both species also have highly effective systems of evaporative cooling that permit them to withstand high ambient temperatures with little elevation in body temperatures (Lasiewski and Bartholomew, 1966; Lasiewski and Dawson, 1964). As similar studies dealing with the physiology of small owls are lacking, I carried out investigations on several members of this group in conjunction with my study of the Elf Owl, Micrathene whitneyi (Ligon, 1968).

Current Status of the Elf Owl in the Southwestern United States

Current Status of the Elf Owl in the Southwestern United States

Further Notes on the Birds of the Baboquívari Mountains, Arizona

The Baboquivari Mountains lie in southern Pima County, extending from near the Mexican border north for about thirty miles. Like Mr. Bruner, I stayed at Fresnal Ranch in the northern part of the range. This ranch is about 4000 feet above sea level. Baboquivari Peak, the highest mountain in the chain, is a nearly barren mass of precipitous rock jutting up from a low ridge several miles southwest of the ranch. The second greatest altitude is attained by Fresnal Hill, which adjoins Baboquivari Peak on the north; well forested above, it reaches an elevation of roughly 7000 feet. My observations were almost entirely limited to the lower parts of the northern fifth of the range, and most of the birds were seen near the ranch in Otero Canyon. This canyon and its tributaries are well forested along the water-courses of their northern slopes. The commonest trees are mesquite, live oak, juniper, and pinyon. There was plenty of water in the mountains throughout my stay. My work, which was greatly facilitated by Mr. Bryarn Peters, owner of Fresnal Ranch, was done mainly between December 20, 1931, and June 3, 1932, though a few records were obtained as early as October 1, 1931. No birds were collected. The preparation of these notes was made possible through the extreme kindness of Mrs. Florence Merriam Bailey. All the birds listed by Mr. Bruner were again found except six: California Brown Pelican, Wilson Phalarope, Whitney Elf Owl, Yellow-headed Blackbird, Long-tailed Chat, and Painted Redstart.

The Elf Owl in California

The Elf Owl in California

The Elf Owl as a California Bird

The Elf Owl as a California Bird