William Herschel Observed Flattened Polar Regions on Uranian Disk

Summary: German-British astronomer William Herschel observed flattened polar regions on the Uranian disk during his 10-year study of the planet’s shape.

artist’s concept of Uranian ring system in polar rotation as discovered by NASA Ames C-141 Kuiper Airborne Observatory; Rick Guidice / NASA Ames Research Center; NASA ID ARC-1977-AC77-1069; date created 1977-09-12: Generally not subject to copyright in the United States, via NASA Image and Video Library

German-British astronomer William Herschel observed flattened polar regions on the Uranian disk, according to his observational journal notes on his 10-year study of the planet’s shape.

William Herschel (Nov. 15, 1738-Aug. 25, 1822) reported his findings about the shape of Uranus at the Dec. 14, 1797, meeting of The Royal Society of London (known officially as The Royal Society for Improving Natural Knowledge). His analysis of the Uranian disk also considered the possibility of a ring system as explaining observations of a not-round, or elliptical, shape.

Herschel had discovered the planet on March 13, 1781. He referred to his planetary discovery as Georgium Sidus (George’s Star) or the Georgian planet, in honor of his royal patron, George III (June 4, 1738-Jan. 29, 1820).

The first entry presented in Herschel’s 1797 report dated back to Nov. 13, 1782. The entry noted: “7-feet reflector, power 460. I perceive no flattening of the polar region” (page 67).

On April 8, 1783, however, his entry stated: “I surmise a polar flattening.”

His entry for March 4, 1787, considered: “I begin to entertain again a suspicion that the planet is not round.” This entry also suggested “a double ring” as explaining the disk’s “double, opposite points.”

Herschel’s entry for March 5, 1792, read: “I viewed the Georgian planet with a newly polished speculum, of an excellent figure. It shewed the planet very well defined, and without any suspicion of a ring. I viewed it successively with 240, 300, 480, 600, 800, 1200, and 2400; all which powers my speculum bore with great distinctness. I am pretty well convinced that the disk is flattened.”

In his report, Herschel explained that, during his March 5 viewings, “The moon was pretty near the planet” (page 69).

The last two observations that Herschel presented in his report occurred in 1794 and 1795. The entries offered clear descriptions of an elongated Uranian disk.

Herschel’s Feb. 26, 1794, entry observed: “20-feet reflector, power 480. The planet seems to be a little lengthened out, in the direction of the longer axis of the satellites’ orbits.”

His April 21, 1795, entry stated: “10-feet reflector, power 400. The telescope adjusted to a neighbouring star, so as to make it perflectly round. The disk of the planet seems to be a little elliptical. With 600, also adjusted upon the neighbouring star, the disk still seems elliptical.”

In his report, Herschel evaluated the observations that he had obtained “. . . in the course of ten years . . .” (page 70). With respect to the Georgian planet’s ring system, he determined the absence of any “. . . ring in the least resembling that, or rather those, of Saturn” (page 70).

Herschel was able to make a positive summation of his consideration of flattened polar regions on the Uranian disk. He reported:

“The flattening of the poles of the planet seems to be sufficiently ascertained by many observations. The 7-feet, the 10-feet, and the 20-feet instruments, equally confirm it; and the direction pointed out Feb. 26, 1794, seems to be conformable to the analogies that may be drawn from the situation of the equator of Saturn, and of Jupiter.

“This being admitted, we may without hesitation conclude, that the Georgian planet also has a rotation upon its axis, of a considerable degree of velocity” (pages 70-71).

A planetary disk’s flattened shape, also known as ellipticity or oblateness, is a function of the equatorial and polar radii, according to planetary physicists Jason W. Barnes and Jonathan J. Fortney’s article in the May 1, 2003, issue of The Astrophysical Journal. The planet’s axial rotation redistributes mass from the polar regions to the equator via centripetal acceleration. The attraction of more mass toward the equatorial plane ensues from Tthe altering of the planet’s gravitational field by the redistributed mass.

Uranus has an ellipticity of 0.02293 as compared with Earth’s flattening of 0.00335, according to planetary curation scientist David Richard Williams’ “Uranus Fact Sheet” on the NASA (National Aeronautics and Space Administration) GSFC (Goddard Space Flight Center) Space Science Data Coordinated Archive (NSSDCA) website. William Herschel’s ice giant planet completes a sidereal rotation in 17.24 hours, as compared with Earth’s period of 23.9345 hours.

The takeaways for William Herschel’s observations of flattened polar regions on the Uranian disk are that the German-British astronomer presented his findings at the Dec. 14, 1797, meeting of The Royal Society of London; that he combined his examination of the shape of the Uranian disk with an evaluation of a possible Uranian ring system; and that he cited his observation on Feb. 26, 1794, as critical to his determination of the planet’s flattened polar regions.

ringless view of Uranus taken Jan. 14, 1986, by spacecraft Voyager 2’s ISS (Imaging Science Subsystem) narrow-angle camera (NAC) from an approximate distance of 7.8 million miles (12.7 million kilometers); NASA ID: PIA18182; image addition date 1986-12-18; image credit NASA / JPL (Jet Propulsion Laboratory)-Caltech: May be used for any purpose without prior permission, via NASA JPL Photojournal

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

artist’s concept of Uranian ring system in polar rotation as discovered by NASA Ames C-141 Kuiper Airborne Observatory; Rick Guidice / NASA Ames Research Center; NASA ID ARC-1977-AC77-1069; date created 1977-09-12: Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library @ https://images.nasa.gov/details-ARC-1977-AC77-1069

ringless view of Uranus taken Jan. 14, 1986, by spacecraft Voyager 2’s ISS (Imaging Science Subsystem) narrow-angle camera (NAC) from an approximate distance of 7.8 million miles (12.7 million kilometers); NASA ID: PIA18182; image addition date 1986-12-18; image credit NASA / JPL (Jet Propulsion Laboratory)-Caltech: May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA18182;
Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library @ https://images.nasa.gov/details-PIA18182

For further information:

Barnes, Jason W.; and Jonathan J. Fortney. “Measuring the Oblateness and Rotation of Transiting Extrasolar Giant Planets.” The Astrophysical Journal, vo. 588 (May 1, 2003): 545-556.
Available via IOPscience @ https://iopscience.iop.org/article/10.1086/373893/pdf

Dreyer, J.L.E. (John Louis Emil), comp. The Scientific Papers of Sir William Herschel Including Early Papers Hitherto Unpublished. Vol. I; Vol. II. London, England: The Royal Society and The Royal Astronomical Society, 1912.
Vol. I: Available via HathiTrust @ https://babel.hathitrust.org/cgi/pt?id=mdp.39015010954678
Vol. II: Available via HathiTrust @ https://babel.hathitrust.org/cgi/pt?id=mdp.39015010954744
Vol. I: Available via Internet Archive @ https://archive.org/details/scientificpapers032804mbp/
Vol. II: Available via Internet Archive @ https://archive.org/details/scientificpapers02hersuoft/

Herschel, Mr. (William). “XXXII. Account of a Comet. Communicated by Dr. Watſon. Read April 26, 1781.” Philosophical Transactions of the Royal Society of London. Vol. LXXI. For the Year 1781. Part II: 492-501. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXII (1782).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51826184

Herschel, William. “Observations and Reports Tending to the Discovery of One or More Rings of the Georgian Planet, and the Flattening of Its Polar Regions.” Pages 67-71. “III. On the Discovery of Four Additional Satellites of the Georgium Sidus. The Retrograde Motion of its Old Satellites Announced; and the Cause of Their Disappearance at Certain Distances From the Planet Explained. Read December 14, 1797.” Philosophical Transactions of the Royal Society of London. For the Year MDCCXCVIII, [vol. LXXXVIII (88)], Part I: 47-79. London, England: Peter Elmsly, Printer to The Royal Society, MDCCXCVIII (1798).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/49109940

Herschel, William. “III. On the Discovery of Four Additional Satellites of the Georgium Sidus. The Retrograde Motion of its Old Satellites Announced; and the Cause of Their Disappearance at Certain Distances From the Planet Explained. Read December 14, 1797.” Philosophical Transactions of the Royal Society of London. For the Year MDCCXCVIII, [vol. LXXXVIII (88)]], Part I: 47-79. London, England: Peter Elmsly, Printer to The Royal Society, MDCCXCVIII (1798).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/49109920
Available via Royal Society of London Publishing @ https://royalsocietypublishing.org/doi/pdf/10.1098/rstl.1798.0005

Herschel, William. “Remarks Upon the Foregoing Observations.” Pages 69-71. “III. On the Discovery of Four Additional Satellites of the Georgium Sidus. The Retrograde Motion of its Old Satellites Announced; and the Cause of Their Disappearance at Certain Distances From the Planet Explained. Read December 14, 1797.” Philosophical Transactions of the Royal Society of London. For the Year MDCCXCVIII, [vol. LXXXVIII (88)], Part I: 47-79. London, England: Peter Elmsly, Printer to The Royal Society, MDCCXCVIII (1798).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/49109942

Levy, David H. Skywatching. Revised and updated. San Francisco CA: Fog City Press, 1994.

Marriner, Derdriu. “Stuart Eves Credits William Herschel With Uranian Epsilon Ring in 1789.” Earth and Space News. Wednesday, Feb. 16, 2011.
Available @

Marriner, Derdriu. “William Herschel First Glimpsed Uranian Ring System on March 4, 1787.” Earth and Space News. Wednesday, Feb. 9, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/02/william-herschel-first-glimpsed-uranian.html

Marriner, Derdriu. “William Herschel Saw Uranian Rings But Puzzling Views Created Doubt.” Earth and Space News. Wednesday, Feb. 9, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/02/william-herschel-saw-uranian-rings-but.html

Williams, David R. (Richard), Dr. “Uranus Fact Sheet.” NASA GSFC (Goddard Space Flight Center) NSSDC (NASA Space Science Data Coordinated Archive) > Solar System Exploration > Planetary Science > Uranus.
Available @ https://nssdc.gsfc.nasa.gov/planetary/factsheet/uranusfact.html

North American Common Raven Habitats: Black Body, Cup Nest, Green Egg

Summary: North American common raven habitats year-round from Alaska and Canada southwestward into Central America get black bodies from green eggs in cup nests.

In sunlight, iridescence accounts for a blue or purple sheen in the black plumage of the North American common raven (Corvus corax); Cypress Provincial Park, Metro Vancouver Regional District (MVRD), southwestern British Columbia, western Canada; October 2007: Clayoquot, CC BY SA 3.0 Unported, via Wikimedia Commons

North American common raven habitats afford cultivators clean lifestyles through Corvidae family predatory wildlife associations with carrion and garbage and naturalists distribution ranges from Canada to the coastal United States and Mexico.

Common ravens bear their common name for widespread abundance and from sounds audible one mile (1.61 kilometers) away and the scientific name Corvus corax (raven raven). Ornithologists consider seven to 10 Africa-, America-, Asia-, Europe-based subspecies subsequent to Carl Linnaeus's (May 23, 1707-Jan. 10, 1787) nominate Corvus corax corax classification in 1758. Bill shapes, body sizes, color subtleties and distribution ranges drive subdivisions into canariensis, clarionensis, hispanus, kamtschaticus, laurencei (or subcorax), principalis, sinuatus, tibetanus, tingitanus and varius subspecies.

Fifteen-year lifespans expect every habitat in all of Alaska and Canada, most of Mexico and the United States in the Appalachians and west of the Rockies.

February through April facilitate brooding one three- to seven-egg clutch in crevices or tree forks or on ledges at 45- to 80-foot (13.72- to 24.38-meter) heights.

Monogamous parents-to-be gather branches, earth, gorse, grapevines, grass, heather, moss, sticks and twigs into bark-, fur-, grass-, leaf-, moss-, wool-lined cups atop the previous year's nests. Six-inch- (15.24-centimeter-) deep, 2- to 4-foot (0.61- to 1.22-meter) inner, 1-foot (0.31-centimeter) outer diameter nests house non- or semi-glossy, rough or smooth, subelliptical to oval eggs. Mothers-to-be initiate 18- to 25-day incubations before the last black-, gray-, olive-, olive- or purple-brown-blotched, mottled, speckled, spotted, streaked, blue-green, brown-green or olive-green egg is laid.

Predatory American martens, bald eagles, coyotes, golden eagles, great horned owls, human hunters, northern goshawks, peregrine falcons and red-tailed hawks jeopardize North American common raven habitats.

Hatchlings of 1.58- to 2.68-inch (40- to 68-millimeter) by 1.14- to 1.58-inch (29- to 40-millimeter) eggs know brown, short, thick down on backs, heads and thighs.

Purple-pink mouths and yellow-flesh gape flanges let clumsy, helpless hatchlings live off food from both parents before leaving cup nests five to six weeks after hatching. Nestlings, always hatched from eggs laid one day apart, maintain contact with parents from roosts no more than 20 miles (32.19 kilometers) away from birth nests. Adults need acorns, almonds, barley, berries, buds, carrion-fed beetles, corn, crustaceans, fish, frogs, fruits, grasshoppers, lizards, maggots, mice, scorpions, seeds, spiders, tortoises, walnuts, wheat and worms.

North American common raven habitats up to 16,404.2-foot (5,000-meter) altitudes above sea level offer winter's coldest temperatures at minus 60 degrees Fahrenheit (minus 51.11 degrees Celsius).

Almonds, apples, blueberries, cherries, cranberries, dogwood, figs, grapes, hemlock, oak, peanuts, poison-ivy, poison-oak, pokeberries, pumpkins, sumac, sunflowers, walnuts and white pine promote common raven life cycles.

Brown and dull black, non-glossy plumage, diminutive sizes and eyes browning from initial blue-gray versus smaller sizes respectively qualify as juvenile and as mature female hallmarks. Adult males reveal black curved bills, flared outer wing feathers, glossy purple-black upper-parts, gray necks, large heads, long feet, shaggy throats, strong legs and wedge-shaped tails. Acrobatic, direct, steady soaring on 3.81- to 3.87-foot (1.16- to 1.18-meter) wingspans suggest 22.05- to 27.16-inch (56- to 69-centimeter), 24.3- to 57.32-ounce (689- to 1,625-gram) adults.

North American common raven habitats teem with 33 sounds, from carrying, deep, grating, gurgling, harsh, rasping, shrill clucks, croaks and knocks to krruuk and tok vocalizations.

illustration of egg of common raven; Henry Seebohm, Coloured Figures of the Eggs of British Birds (1896), Plate 55 (between pages 224-225): Public Domain, via Biodiversity Heritage Library

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

In sunlight, iridescence accounts for a blue or purple sheen in the black plumage of the North American common raven (Corvus corax); Cypress Provincial Park, Metro Vancouver Regional District (MVRD), southwestern British Columbia, western Canada; October 2007: Clayoquot, CC BY SA 3.0 Unported, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Raven_Cypress_Provincial_Park_2.JPG

illustration of egg of common raven; Henry Seebohm, Coloured Figures of the Eggs of British Birds (1896), Plate 55 (between pages 224-225): Public Domain, via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/7272603

For further information:

Baicich, Paul J.; and Harrison, Colin J.O. Nests, Eggs, and Nestlings of North American Birds. Second edition. Princeton NJ: Princeton University Press, Princeton Field Guides, 2005.

Brünnich, M. Th. (Morten Thrane). MDCCLXIV (1764). "28. Corvus varius." Ornithologia Borealis, pages 8-9. Hafniae (Copenhagen, Denmark): J.C. Kall.
Available via MDZ (Münchener DigitalisierungsZentrum Digitale Bibliothek) Digitale Sammlungen @ http://reader.digitale-sammlungen.de/en/fs1/object/display/bsb10306825_00018.html

Dybowski, Benedykt. 1883. "50. Corvus corax kamtschaticus." Bulletin de la Société Zoologique de France, huitième volume: 362-363.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/11227165

Grzimek's Animal Life Encyclopedia, 2nd edition. Volumes 8-11, Birds I-IV, edited by Michael Hutchins, Jerome A. Jackson, Walter J. Bock and Donna Olendorf. Farmington Hills MI: Gale Group, 2002.

Hartert, E. (Ernst); O. (Otto) Kleinschmidt. February 1901. "Verzeichniss der Brehm'schen Sammlung. I. Die Formen von Corvus corax L.: 4. Canarische Inseln. Corvus corax canariensis nom. nov." Novitates Zoologicae, vol. VIII (1901), no. 1 (February): 45. London and Aylesbury UK: Hazell, Watson, and Viney Ltd.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/3268074

Hartert, E. (Ernst); O. (Otto) Kleinschmidt. February 1901. "Verzeichniss der Brehm'schen Sammlung. I. Die Formen von Corvus corax L.: 5. Spanien. Corvus corax hispanus nom. nov." Novitates Zoologicae, vol. VIII (1901), no. 1 (February): 45. London and Aylesbury UK: Hazell, Watson, and Viney Ltd.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/3268074

Horsfield, Thomas. 1849. "XX. Brief Notice of Several Mammalia and Birds Discovered by B.H. Hodgson, Esq., in Upper India: 2. Corvus Tibetanus Hodgs." The Annals and Magazine of Natural History, Including Zoology, Botany, and Geology, vol. III-second series, no. XV: 203. London UK: R. and J.E. Taylor.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/16085494

Hume, A.O. (Allan Octavian). 1873. "Corvus Laurencei." Lahore to Yārkand. Incidents of the Route and Natural History of the Countries Traversed, Part II Natural History, Chapter I Ornithology: 235. London UK: L. Reeve & Co.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/47162062 Available via Internet Archive @ https://archive.org/stream/lahoretoyrkandi00humegoog#page/n332/mode/1up

Irby, Howard, Lieut-Col. July 1874. "Notice of an Apparently Undescribed Species of Corvus From Tangier: Corvus tingitanus n. sp." The Ibis, vol. IV-third series (1874), no. XV (July): 264-266. London UK: John Van Voorst.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/8617106

Linnaeus, Carl. 1758. "1. Corvus corax." Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis, Tomus I, Editio Decima, Reformata: 105. Holmiae [Stockholm, Sweden]: Laurentii Salvii [Laurentius Salvius].
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/727010

Peterson, Alan P., M.D. "Corvus corax Linnaeus 1758." Zoonomen: Zoological Nomenclature Resource > Birds of the World -- Current Valid Scientific Avian Names > Passeriformes > Corvidae > Corvus.
Available @ http://www.zoonomen.net/avtax/pass.html

Ridgway, Robert. 1887. "C. corax principalis Ridgw. Northern Raven." A Manual of North American Birds, page 361. Philadelphia PA: J.P. Lippincott Co.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/7567616

Rothschild, Walter; Ernst Hartert. July 1902. "Further Notes on the Fauna of the Galápagos Islands: Corvus corax clarionensis subsp. nov." Novitates Zoologicae, vol. IX (1902), no. 2 (July): 381. London and Aylesbury UK: Hazell, Watson, and Viney Ltd.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/3268736

Seebohm, Henry. 1896. Coloured Figures of the Eggs of British Birds, With Descriptive Notices. Sheffield UK: Pawson and Brailsford.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/7272247

Wagler, Johann Georg. 1829. "C. sinuatus." Isis von Oken, jahrgang 1829 (band XXII), heft VII: 748. Leipzig, Germany: Brockhaus.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/27011942

American Loggerhead Shrike Habitats: Gray Bodies, Cup Nests, Pale Eggs

Summary: North American loggerhead shrike habitats seasonally in Canada, year-round in Mexico and the United States claim gray bodies from pale eggs in cup nests.

loggerhead shrike (Lanius ludovicianus); Queen Valley, northwestern Joshua Tree National Park, southeastern California; Feb. 4, 2010: Robb Hannawacker/National Park Service/Joshua Tree National Park, Public Domain, via Flickr

North American loggerhead shrike habitats accept cultivators through Laniidae family predatory wildlife associations with plant-damaging pests and naturalists through distribution ranges seasonally in Canada and year-round in Mexico and the United States.

Loggerhead shrikes bear their common name as large-headed shriekers and the scientific name Lanius ludovicianus (butcher of Louisiana) from prey impalement practices of 18th-century Louisiana-dwelling shrikes. Ornithologists consider as the nominate subspecies, clustered today from Virginia to Florida, Carl Linnaeus's (May 23, 1707-Jan. 10, 1787) classification in 1766 of Lanius ludovicianus ludovicianus. They discuss such other subsequently described subspecies as Lanius ludovicianus anthonyi, excubitorides (synonymous with gambeli and sonoriensis), grinnelli, mearnsi, mexicanus (synonymous with nelsoni), miamensis and migrans.

Mysterious lifespans expect open or semi-open fields, orchards, parklands, pastures, scrublands, semi-deserts and woodlands with high-vantage, scattered perches in dense-leafed bushes, hedgerows, shelterbelts, shrubs and trees.

February through June facilitate two to three four- to seven-egg clutches at 3- to 30-foot (0.91- to 9.14-meter) heights, preferably in elm, fir, hackberry or Osage-orange.

Parents-to-be gather bark, grasses, stems, sticks and twigs for mothers-to-be to generate into bark-, cotton-, down-, feather-, hair-, rootlet-lined cup nests within six to 11 days. Cup nests hidden in dense foliage or Spanish moss house non-glossy, smooth, 0.91- to 1.06-inch (24- to 25-millimeter-) by 0.71- to 0.79-inch (18.7- to 20-millimeter) eggs. Mothers-to-be initiate 14- to 17-day incubations with the next-to-last brown-, buff-, gray- or purple-blotched, speckled or spotted, pale-banded buff, creamy white, dull white or gray egg.

Agro-industrialists, black rat-snakes, blue jays, crows, drivers, house wrens, kestrels, magpies, owls, raccoons, red-tailed hawks, sharp-shinned hawks, starlings and weasels jeopardize North American loggerhead shrike habitats.

Fathers-to-be keep incubating mates fed with ground-foraged, nest-portioned food while mothers-to-be keep light, moisture and temperature levels hatch-friendly by rotating and shielding incubating eggs from harm. Helpless hatchlings look bright orange because of naked skin, buff-yellow because of bills, white because of sparse down and yellow because of gape flanges and mouths. Fathers, then both parents, maintain food supplies while hatchlings manage feathering as 15-day-olds, nearby roosts as 17- to 21-day-olds and physical independence as 40- to 45-day-olds. Adults need carrion, crickets, frogs, goldfinches, grasshoppers, ground beetles, ground squirrels, lizards, mice, mourning doves, northern cardinals, roadkill, shrews, snakes, sparrows, turtles, verdins, voles and warblers.

North American loggerhead shrike habitats up to 6,561.68 feet (2,000 meters) above sea level offer winter-coldest temperatures at minus 15 degrees Fahrenheit (minus 26.11 degrees Celsius).

Apple, ash, chittamwood, cottonwood, cypress, fir, grapevine, greenbrier, hawthorn, holly, locust, mesquite, mulberry, oak, pear, pine, plum, red-cedar, rose, soapberry, spruce, tree-of-heaven and willow prove shrike-friendly.

Barred, brown-gray bodies, brown masks, buff-barred wings and pale-based lower beaks versus brown upper-parts, faint-marked breasts and minimal masks respectively quicken juvenile and mature female identifications. Black eyes and masks, black hooked bills, gray crowns, feet, legs, underparts and upper-parts, white chins, white-edged, black, rounded tails and white-flashed black wings reveal adults. Fast-beat, gliding, swooping flight on 11.02- to 12.59-inch (28- to 32-centimeter) wingspans suggest 7.87- to 9.06-inch (20- to 23-centimeter), 1.24- to 2.12-ounce (35- to 60-gram) adults.

North American loggerhead shrike habitats transmit harsh chaa-chaa-chaa songs, trills and warbles seasonally north of, and seasonally and year-round south of and within, United States' borders.

illustration of eggs and nest of loggerhead shrike (Lanius ludovicianus) under scientific synonym of Collurio ludovicianus; Illustrations of the Nests and Eggs of Birds of Ohio, Plate IX, between pages 56-57: Public Domain, via Biodiversity Heritage Library

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

loggerhead shrike (Lanius ludovicianus); Queen Valley, northwestern Joshua Tree National Park, southeastern California; Feb. 4, 2010: Robb Hannawacker/National Park Service, Public Domain, via Joshua Tree National Park @ Flickr @ https://www.flickr.com/photos/joshuatreenp/12488581405/

illustration of eggs and nest of loggerhead shrike (Lanius ludovicianus) under scientific synonym of Collurio ludovicianus; Illustrations of the Nests and Eggs of Birds of Ohio, Plate IX, between pages 56-57: Public Domain, via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/34907627

For further information:

Baicich, Paul J.; and Harrison, Colin J.O. Nests, Eggs, and Nestlings of North American Birds. Second edition. Princeton NJ: Princeton University Press, Princeton Field Guides, 2005.

Grzimek's Animal Life Encyclopedia, 2nd edition. Volumes 8-11, Birds I-IV, edited by Michael Hutchins, Jerome A. Jackson, Walter J. Bock and Donna Olendorf. Farmington Hills MI: Gale Group, 2002.

Jones, Howard. 1886. Illustrations of the Nests and Eggs of Birds of Ohio. Illustrations by Mrs. N.E. Jones. Vol. I. Circleville OH: s.n. (sine nomine).
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/34907587

Linnaeus, Carl. 1766. "6. Lanius ludovicianus." Systema Naturae, tomus I: 134. Editio Duodecima, Reformata. Holmiae [Stockholm, Sweden]: Laurentii Salvii [Laurentius Salvius].
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/42946330

Peterson, Alan P., M.D. "Lanius ludovicianus Linnaeus 1766." Zoonomen: Zoological Nomenclature Resource > Birds of the World -- Current Valid Scientific Avian Names > Passeriformes > Laniidae > Lanius.
Available @ http://www.zoonomen.net/avtax/pass.html

Stuart Eves Credits William Herschel With Uranian Epsilon Ring in 1789

Summary: Surrey Satellite Technology Limited’s Stuart Eves suggests William Herschel saw Uranian epsilon ring in 1789, in a new look at Herschel’s notes.

Uranus and the planet's outermost ring, the epsilon ring; computerized summation of six images obtained Nov. 28, 1985, by spacecraft Voyager 2’s ISS (Imaging Science Subsystem) narrow-angle camera (NAC) from a range of 72.3 million kilometers (44.9 million miles); NASA ID ARC-1985-A86-7001; image credit NASA / JPL-Caltech: Generally not subject to copyright in the United States, via NASA Image and Video Library

Surrey Satellite Technology Limited’s Stuart Eves suggests William Herschel saw the Uranian epsilon ring in 1789, according to the astrophysicist and space safety expert’s new look at the German-British astronomer’s observations.

Dr. Stuart Eves officially presented his new look at Uranian ring observations made by William Herschel (Nov. 15, 1738-Aug. 25, 1822) at the 2007 National Astronomy Meeting. The Royal Astronomical Society (RAS) held the prestigious annual conference from Monday, April 16, to Friday, April 20, 2007, at the University of Central Lancashire’s (UCLan) Centre for Astrophysics in Preston, North West England.

William Herschel (Nov. 15, 1738-Aug. 25, 1822) shared findings from his 10-year search for a Uranian ring system at the Royal Society of London’s Dec. 14, 1797, meeting. He reported ringed and ringless observations.

Herschel extensively described ringed views that he obtained on March 16, 1789. “The ring is short, not like that of Saturn . . . . It is remarkable that the two annae seem of a colour a little inclined to red . . . .” (page 68).

In his “Remarks Upon the Foregoing Observations,” however, Herschel cited a ringless view as critical to his assessment of a ringless system. “Placing therefore great confidence on the observation of March 5, 1792, supported by my late views of the planet, I venture to affirm, that it has no ring in the least resembling that, or rather those, of Saturn” (page 70).

Yet, in a post-1792 observation, he had noted: “Dec. 4, 1793. 7-feet reflector, power 287. The Georgian planet is not so well defined as, from the extraordinary distinctness of my present 7-feet telescope, it ought to be. There is a suspicion of some apparatus about the planet” (page 69).

In a re-evaluation of Herschel’s annular observations, Dr. Eves finds a consistent rightness of details with the Uranian system’s now-known epsilon (ε) ring.

In an April 16, 2007, press release, Royal Astronomical Society press officers Robert Massey and Anita Heward reveal: “Herschel got a lot of things right, notes Dr. Eves. He has a ring of roughly the correct size relative to the planet, and he also has the orientation of this ring in the right direction. In addition, he accurately describes the way the appearance of the ring changes as Uranus moves around the Sun, and he even gets its colour right. Uranus’s Epsilon ring is somewhat red in color, a fact only recently confirmed by the Keck telescope, and Herschel mentions this in his paper.”

Dr. Eves offers several explanations for the lack of observations of the Uranian ring system in the 190 years between Herschel’s discernments, which date back, at least, to March 4, 1787, and the serendipitous detection of at least five rings on March 10,1977, via the Kuiper Airborne Observatory. The planet’s extremely tilted axial geometry greatly limits the opportunities for Earth-based observations of the Uranian ring system.

Also, Dr. Eves references the Cassini-Huygens spacecraft’s observations of the darkening of the Saturnian ring system as a process that might also affect the Uranian ring system. The unknown brightening-darkening phenomena could have operated to brighten the Uranian ring system in the late 18th century.

“If these same mechanisms are also operating at Uranus, then the appearance of its rings could have changed quite markedly over 200 years, making them much harder to detect. Herschel’s observations could thus be proof that planetary ring systems in our solar system are far more dynamic than has previously been supposed,” notes the Royal Astronomical Society’s press release.

Earth’s atmosphere could also interfere with the ring system’s observability, according to BBC News science reporter Paul Rincon’s April 18, 2007, article on Dr. Eves’ presentation. The light pollution and smog created by the Industrial Revolution, which approximately began in the last half of the 18th century, have disturbed the clarity of the night sky environment.

The takeaway for Surrey Satellite Technology Limited’s Stuart Eve’s suggestion that William Herschel could have seen the Uranian epsilon ring is that the astrophysicist and space security expert’s new look at Herschel’s 1797 report of ringed and ringless views of Uranus finds details in the German-British astronomer’s descriptions that accord with the Uranian ring system.

high-resolution image of Uranian system’s bright outer ring, the epsilon ring, obtained Jan. 23, 1986, from a distance of 1.12 million kilometers (690,000 miles) by Voyager 2’s ISS (Imaging Science Subsystem) narrow-angle camera (NAC); the approximate width of 100 kilometers (60 miles) at this section of the epsilon ring shows structural variations of a broad, bright outer component, approximately 40 kilometers (25 miles) wide; a comparably wide, darker middle region; and a narrow, brighter inner strip, approximately 15 kilometers (9 miles) in width; NASA ID PIA01983; ARC-1986-A86-7022; P-2950BW; NASA ID PIA01983; image addition date 1999-06-30; image credit NASA / JPL: May be used for any purpose without prior permission, via NASA JPL Photojournal

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Uranus and the planet's outermost ring, the epsilon ring; computerized summation of six images obtained Nov. 28, 1985, by spacecraft Voyager 2’s ISS (Imaging Science Subsystem) narrow-angle camera (NAC) from a range of 72.3 million kilometers (44.9 million miles); NASA ID ARC-1985-A86-7001; image credit NASA / JPL-Caltech: Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library @ https://images.nasa.gov/details-ARC-1985-A86-7001

high-resolution image of Uranian system’s bright outer ring, the epsilon ring, obtained Jan. 23, 1986, from a distance of 1.12 million kilometers (690,000 miles) by Voyager 2’s ISS (Imaging Science Subsystem) narrow-angle camera (NAC); the approximate width of 100 kilometers (60 miles) at this section of the epsilon ring shows structural variations of a broad, bright outer component, approximately 40 kilometers (25 miles) wide; a comparably wide, darker middle region; and a narrow, brighter inner strip, approximately 15 kilometers (9 miles) in width; NASA ID PIA01983; ARC-1986-A86-7022; P-2950BW; NASA ID PIA01983; image addition date 1999-06-30; image credit NASA / JPL: May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA01983;
Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library @ https://images.nasa.gov/details-PIA01983

For further information:

De Pater, Imke; H.B. Hammel; Mark R. Showalter; and Marcos A. van Dam. “The Dark Side of the Rings of Uranus.” Science, vol. 317, issue 5846: 1888-1890. DOI: 10.1126/science.1148103
Available via AAAS Science @ https://science.sciencemag.org/content/317/5846/1888
Available via ResearchGate @ https://www.researchgate.net/publication/6123185_The_Dark_Side_of_the_Rings_of_Uranus

Dreyer, J.L.E. (John Louis Emil), comp. The Scientific Papers of Sir William Herschel Including Early Papers Hitherto Unpublished. Vol. I; Vol. II. London, England: The Royal Society and The Royal Astronomical Society, 1912.
Vol. I: Available via HathiTrust @ https://babel.hathitrust.org/cgi/pt?id=mdp.39015010954678
Vol. II: Available via HathiTrust @ https://babel.hathitrust.org/cgi/pt?id=mdp.39015010954744
Vol. I: Available via Internet Archive @ https://archive.org/details/scientificpapers032804mbp/
Vol. II: Available via Internet Archive @ https://archive.org/details/scientificpapers02hersuoft/

Fountain, Henry. “In a Rare View, Rings on Uranus Show Their Changes.” The New York Times > Science > Observatory. Aug. 28, 2007.
Available @ https://www.nytimes.com/2007/08/28/science/28obring.html

Herschel, William. “Observations and Reports Tending to the Discovery of One or More Rings of the Georgian Planet, and the Flattening of Its Polar Regions.” Pages 67-71. “III. On the Discovery of Four Additional Satellites of the Georgium Sidus. The Retrograde Motion of its Old Satellites Announced; and the Cause of Their Disappearance at Certain Distances From the Planet Explained. Read December 14, 1797.” Philosophical Transactions of the Royal Society of London. For the Year MDCCXCVIII, [vol. LXXXVIII (88)], Part I: 47-79. London, England: Peter Elmsly, Printer to The Royal Society, MDCCXCVIII (1798).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/49109940

Herschel, William. “III. On the Discovery of Four Additional Satellites of the Georgium Sidus. The Retrograde Motion of its Old Satellites Announced; and the Cause of Their Disappearance at Certain Distances From the Planet Explained. Read December 14, 1797.” Philosophical Transactions of the Royal Society of London. For the Year MDCCXCVIII, [vol. LXXXVIII (88)]], Part I: 47-79. London, England: Peter Elmsly, Printer to The Royal Society, MDCCXCVIII (1798).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/49109920
Available via Royal Society of London Publishing @ https://royalsocietypublishing.org/doi/pdf/10.1098/rstl.1798.0005

Herschel, William. “Remarks Upon the Foregoing Observations.” Pages 69-71. “III. On the Discovery of Four Additional Satellites of the Georgium Sidus. The Retrograde Motion of its Old Satellites Announced; and the Cause of Their Disappearance at Certain Distances From the Planet Explained. Read December 14, 1797.” Philosophical Transactions of the Royal Society of London. For the Year MDCCXCVIII, [vol. LXXXVIII (88)], Part I: 47-79. London, England: Peter Elmsly, Printer to The Royal Society, MDCCXCVIII (1798).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/49109942

Lavoie, Sue, site manager. “PIA01983: Epsilon Ring of Uranus.” NASA Jet Propulsion Laboratory Photojournal. Image addition date 1999-06-30.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA01983

Levy, David H. Skywatching. Revised and updated. San Francisco CA: Fog City Press, 1994.

Marriner, Derdriu. “William Herschel First Glimpsed Uranian Ring System on March 4, 1787.” Earth and Space News. Wednesday, Feb. 2, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/02/william-herschel-first-glimpsed-uranian.html

Marriner, Derdriu. “William Herschel Saw Uranian Rings But Puzzling Views Created Doubt.” Earth and Space News. Wednesday, Feb. 9, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/02/william-herschel-saw-uranian-rings-but.html

Massey, Robert; and Anita Heward. “Did William Herschel Discover the Rings of Uranus in the 18th Century?” Royal Astronomical Society > Press. April 16, 2007.
Available via Internet Archive Wayback Machine @ https://web.archive.org/web/20120910092417/http://www.nam2007.uclan.ac.uk/press_releases.php?news=20070416b

Moore, Patrick, Sir. Philip’s Atlas of the Universe. Revised edition. London UK: Philip’s, 2005.

New Scientist Monitor Column. “Herschel Saw Rings Round Uranus in 1787.” New Scientist, vol. 74, no. 1052 (May 19, 1977): 396.
Available via Google Books @ https://books.google.com/books?id=Rt5VRWY4aR8C&pg=PA396

Pearson, W. (William), Rev. Plates Belonging to the Second Volume of An Introduction to Practical Astronomy.
Available @ https://digital.tcl.sc.edu/digital/collection/ariail2/id/151

Pearson, W. (William), Rev. “XV. The Herschelian Forty-Feet Telescope (Plate VIII).” An Introduction to Practical Astronomy: Containing Descriptions of the Various Instruments, That Have Been Usefully Employed in Determining the Places of the Heavenly Bodies, With an Account of the Methods of Adjusting and Using Them. Vol. II: 71-78. London, England: Printed for the Author by Messrs. Longman, Rees, Orme, Brown, and Green, 1829.
Available via HathiTrust @ https://hdl.handle.net/2027/nyp.33433090845102?urlappend=%3Bseq=101

Rincon, Paul. “Uranus Rings ‘Were Seen in 1700s.’” BBC News > Science & Environment. April 18, 2007.
Available @ http://news.bbc.co.uk/2/hi/sci/tech/6569849.stm

Schmude, Richard, Jr. “1. The Uranus System: Rings.” Uranus, Neptune, Pluto and How to Observe Them: 27-34. Astronomers’ Observing Guides. New York NY: Springer Science + Business Media LLC, 2008.
Available via ePDF @ https://epdf.pub/uranus-neptune-and-pluto-and-how-to-observe-them-astronomers-observing-guides.html
Available via Google Books @ https://books.google.com/books?id=47azIwooFqEC&pg=PA27

Shiga, David. “Rare View Reveals Dynamic Nature of Uranus’s Rings.” New Scientist > Space. Aug. 23, 2007.
Available @ https://www.newscientist.com/article/dn12529-rare-view-reveals-dynamic-nature-of-uranuss-rings/

SM Dana Centre ‏@DanaCentre. “Have been reading about William Herschel in 'The Age of Wonder'. Looking forward to Stuart Eves' talk on him tonight http://budurl.com/lsf5.” Twitter. Oct. 19, 2010.
Available @ https://twitter.com/DanaCentre/status/27836180852

SM Dana Centre ‏@DanaCentre. “Stuart Eves talks about William Herschel and the rings of Uranus http://budurl.com/ubjm 19 October http://budurl.com/ubjm.” Twitter. Oct. 15, 2010.
Available @ https://twitter.com/DanaCentre/status/27443609239

Young, Kelly. “Uranus Moons Seen Overtaking Each Other for First Time.” NewScientist > Space. May 18, 2007.
Available @ https://www.newscientist.com/article/dn11891-uranus-moons-seen-overtaking-each-other-for-first-time/

American Mourning Dove Habitats: Gray Body, Platform Nest, White Egg

Summary: North American mourning dove habitats seasonal outside the Caribbean, Mexico and the United States year-round get gray bodies, platform nests, white eggs.

mourning dove (Zenaida macroura) in a backyard in Toronto, Golden Horseshoe region, Southern Ontario, east central Canada, 2005: Mdf, CC BY SA 3.0 Unported, via Wikimedia Commons

North American mourning dove habitats abet cultivators with Columbidae dove and pigeon family member appetites for weed seeds and naturalists with distribution ranges year-round from southwestern Canada through Mexico and Caribbean America.

Mourning doves bear their common name for their call and the scientific name Zenaida macroura as a princess's namesake genus and a species' signature long tail. The genus commemorates Zénaïde Laetitia Julie (July 8, 1801-Aug. 8, 1854), wife of ornithologist and prince Charles Lucien Jules Laurent Bonaparte (May 24, 1803-July 29, 1857). Its species divides into the gray-brown, larger carolinensis (Carolina) subspecies east of the Mississippi River and the paler, smaller marginella (marginal) subspecies to the Mississippi's west.

Mourning doves, described in 1758 by Swedish zoologist Carl Linnaeus (May 23, 1707-Jan. 10, 1787), expect 19-year-lifespans in deserts, fields, grasslands, parklands, scrublands, semi-deserts and woodlands.

February through September facilitate brooding two two- to four-egg clutches or more amid vines, at 10- to 50-foot (3.05- to 15.24-meter) heights or on the ground.
Parents-to-be gather sticks and twigs over two to four days into occasionally grass-, rootlet-, weed-lined platform nests sometimes on old grackle, gray catbird or robin nests. Nests house bright white, oval to elliptical, smooth, somewhat glossy, unmarked 0.87- to 1.18-inch- (22- to 30-millimeter-) long, 0.43- to 0.87-inch- (11- to 22-millimeter-) wide eggs. Thirteen- to 15-day incubations of eggs laid alternately and successively in the evening and the morning involve fathers-to-be during the day and mothers-to-be during the night.

Hunting, poisoning from fallen lead shot and from pesticide-riddled prey and predation by black rat snakes, falcons, hawks and raccoons jeopardize North American mourning dove habitats.

Parents-to-be keep helpless hatchlings and nestlings with short, sparse, stringy white down over yellow skin fed through crop-milk secretions from adult female and male neck pouches.

Nestlings learn to fledge as 11- to 13-day-olds even though they leave parent-tended nests in soils and woody plants or on ledges as 25- to 27-day-olds. Mourning doves, physically and sexually mature 85 days after hatching, manage diets of ants, beetles, crickets, grasshoppers and snails; berries, grains, nuts and seeds; and grit. Adults need cereal grains such as barley, corn, millet, oats, rye and wheat; peanuts; and seeds from herbs, sunflowers, trees such as pines and wild grasses.

North American mourning dove habitats up to 8,202.1 feet (2,500 meters) above sea level offer winter-coldest temperatures at minus 45 degrees Fahrenheit (minus 42.77 degrees Celsius).

Acacia, ash, aspen, basswood, beech, birch, cherry, cottonwood, elm, hawthorn, hickory, locust, mahogany, maple, mesquite, oak, persimmon, poplar, sassafras, sugarberry, sycamore, tamarack and willow provide cover. Blackbrush, bluegrass, bluestem, buffalograss, cedar, cordgrass, cypress, fescue, fir, grama-grass, hemlock, needlegrass, oatgrass, palmetto, paloverde, pine, sagebrush, saltbush, sea-oats, spruce, tarbush and wheatgrass qualify as camouflage.

Black-dotted sides of faces, dark, thin bills, dark-spotted gray wings, gray-tan bodies and long, pointed tails reveal pink-legged, pink-toed, rosy-breasted, small-headed adults with neck-mottled, underpart-mottled juveniles. Direct, quick-beat, twisting flight on 14.57- to 17.72-inch (37- to 45-centimeter) wingspans suggest 2.99- to 6.17-ounce (85- to 175-gram), 9.06- to 13.39-inch (23- to 34-centimeter) adults.

North American mourning dove habitats transmit coo, coo-oo and coo-oo-oo calls of perching males, ohr-ohr sounds of nesting females, mellow owl-like hoO-Oo-oo hoo-hoo-hoo vocalizations and whistles.

mourning dove (Zenaida macroura) egg in hanging planter; Friday, Aug. 1, 2003, 17:59: Mr walsh at English Wikipedia, Public Domain, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

mourning dove (Zenaida macroura) in a backyard in Toronto, Golden Horseshoe region, Southern Ontario, east central Canada, 2005: Mdf, CC BY SA 3.0 Unported, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Zenaida_macroura1.jpg

mourning dove (Zenaida macroura) egg in hanging planter; Friday, Aug. 1, 2003, 17:59: Mr walsh at English Wikipedia, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Mourning_Dove_Egg.JPG

For further information:

Baicich, Paul J.; and Harrison, Colin J.O. Nests, Eggs, and Nestlings of North American Birds. Second edition. Princeton NJ: Princeton University Press, Princeton Field Guides, 2005.

Grzimek's Animal Life Encyclopedia, 2nd edition. Volumes 8-11, Birds I-IV, edited by Michael Hutchins, Jerome A. Jackson, Walter J. Bock and Donna Olendorf. Farmington Hills MI: Gale Group, 2002.

Linnaeus, Carl. 1758. "16. Columba macroura." Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis, Tomus I, Editio Decima, Reformata: 164. Holmiae: Laurentii Salvii.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/727071

Linnaeus, Carl. 1766. "37. Columba macroura carolinensis." Systema Naturae, tomus I: 286. Editio Duodecima, Reformata. Holmiae [Stockholm, Sweden]: Laurentii Salvii [Laurentius Salvius].
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/42946482

Peterson, Alan P., M.D. "Zenaida macroura (Linnaeus) 1758." Zoonomen: Zoological Nomenclature Resource > Birds of the World -- Current Valid Scientific Avian Names > Columbiformes > Columbidae > Zenaida.
Available @ http://www.zoonomen.net/avtax/colu.html

Townsend, Chas. H. (Charles Haskins). 1891. "No. XIV. Birds From the Coasts of Western North America and Adjacent Islands, Collected in 1888 and '89, With Descriptions of New Species: I. Clarion Island: Zenaidura clarionensis  sp. nov." Proceedings of the United States National Museum, vol. XIII (1890), no. 799: 133. Washington DC: Government Printing House.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/15670849

Wetmore, Alexander. 12 September 1956. "Additional Forms of Birds From Panamá and Colombia: Zenaidura macroura turturilla subsp. nov." Proceedings of the Biological Society of Washington, vol. 69: 123-125. Baltimore MD: Monumental Printing Co.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/34549817
Available via HathiTrust @ https://hdl.handle.net/2027/uc1.31822006518377?urlappend=%3Bseq=126

Woodhouse, S.W. (Samuel Washington), M.D. June 1852. "Description of a New Species of Ectopistes: Ectopiste marginella, nobis." Proceedings of the Academy of Natural Sciences of Philadelphia, vol. VI (1852, 1853): 104-105. Philadelphia PA: Merrihew & Thompson, 1854.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/1779640

Tree Load Can Turn Tree Health Into Tree Failure or Tree Fatigue

Summary: Jerry Bond, Ph.D. and urban forester, adds tree load to soil quality, stress raisers and tree defects to predict tree failure, tree fatigue or tree health.

snow load and wind load damage to river birch (Betula nigra) during 2002 ice storm: Randy Cyr/Greentree, CC BY 3.0 United States, via Forestry Images

Arborists are the target audience of Tree Load: Concept even though the article's tree health concerns in the February 2011 issue of Arborist News attract master gardeners, master naturalists and tree stewards.

Jerry Bond, consultant with Urban Forestry, LLC, and Ph.D., begins the five-page article with load magnitude and movement as tree failure and tree fatigue probability indicators. He considers load, in terms of tree risk assessment, "the internal force created by the interaction of energy with a structure or one of its parts." He differentiates between complex forces on "organic structures in natural settings" and external, "simple forces exerted on homogeneous and rigid beams as used in mechanical theory."

Load ensues from an energy source's duration, quality, speed and temperature interacting with crown architecture, leaf characteristics and wood density and elasticity and endangers tree health.

Tree load falls into less or more variable categories, with dead load representing "relatively constant" weight of "above-ground wood that increases slowly throughout a tree's life."

More variable categories get designated dynamic regarding earthquakes, tree take-down top removals, vehicular impacts and wind gusts; or environmental respecting horizontal or twisting winds and ice. Live load has a narrow scope for such non-environmental and vertical forces as climbers and their rigging operations and a wide scope for all temporary forces. Designations as static load identify external, long-term, non-varying forces while those of resonance indicate "smaller forces" leading to "large oscillations" and tree fatigue or tree failure.

Categories concerning directional effects around or at right angles or parallel to length and involving less or more temporarily weighted forces join to compromise tree health.

Compression and tension, forces that dominate the axial dimension focus of risk assessment analysis, keep the effects of load paralleling length and running with the grain. Torsion, a circumferential dimension, leads load's effects around tree length while the radial dimension lets effects run across the grain and at right angles to length. Compression makes wood weaker than tension does whereas torsion maximizes such defects as cracked, long leaders and such variables as species-specific shear strength of green wood.

Tree load navigates the apoplastic continuum of columns and rows of interconnected cell walls from the crown's main stem to the roots and into the soil.

The formula of stress equaling force divided by area offers tree fatigue and tree failure if increased force over decreased areas overwhelm tree health and strength.

Absence or presence of severe defects and stress raisers, constancy and direction of load and interactions between strength and stress predict tree failure or tree fatigue.

"[A]n internal condition that leads to high localized stress" qualifies as a stress raiser, be it a bark occlusion, canker, crack, decay, dogleg, hole or notch. Illustrated images reveal the inability of decayed butts and saturated soils to keep trees anchored during violent storms and the vulnerability of cracked, decayed, fungus-riddled limbs. The final paragraphs summarize risk assessment's imagining tree load flow from treetop to root tips, identifying defects and stress raisers and rating tree health and strength.

The article targets arborists even though the author's commitment to making tree load-related lectures and research accessible to the public welcomes non-specialists to "Tree Load: Concept."

common, or European, beech (Fagus sylvatica) with cankers as stress raisers; Sunday, Oct. 28, 2007, 12:25: Frank Vincentz, CC BY SA 3.0 Unported, via Wikimedia Commons

Acknowledgment

My special thanks to:
talented artists and photographers/concerned organizations who make their fine images available on the internet;
University of Illinois at Urbana-Champaign for superior on-campus and on-line resources.

Image credits:

snow load and wind load damage to river birch (Betula nigra) from 2002 ice storm: Randy Cyr/Greentree, CC BY 3.0 United States, via Forestry Images @ http://www.forestryimages.org/browse/detail.cfm?imgnum=1238165

common, or European, beech (Fagus sylvatica) with cankers as stress raisers; Sunday, Oct. 28, 2007, 12:25: Frank Vincentz, CC BY SA 3.0 Unported, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Fagus_sylvatica_-_canker_03_ies.jpg

For further information:

Bond, Jerry. February 2011. "Tree Load: Concept." Arborist News, vol. 20, issue 1 (February 2011): 12-17.
Available @ http://www.isa-arbor.com/myAccount/myEducation/resources/CEU-Feb11.pdf

Gilman, Ed. 2011. An Illustrated Guide to Pruning. Third Edition. Boston MA: Cengage.

Hayes, Ed. 2001. Evaluating Tree Defects. Revised, Special Edition. Rochester MN: Safe Trees.

Marriner, Derdriu. 11 December 2010. “Tree Electrical Safety Knowledge, Precautions, Risks and Standards.” Earth and Space News. Saturday.
Available @ https://earth-and-space-news.blogspot.com/2010/12/tree-electrical-safety-knowledge.html