Terms in this Glossary pertain to Ruby-throated Hummingbirds (Archilochus colubris), their lifestyles, and the plants, animals, or habitats with which they interact. If you have additional words or phrases to add to the list to make it more helpful, or if a definition is not clear, contact the WEBMASTER. Special thanks goes to Rogers George for suggestions and extensive proofreading assistance.


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ACUTE: Having pointed tips, as in the tail feathers of many young birds. See truncate.

Aesculus pavia: Scientific name for Red Buckeye.

AFTER HATCH YEAR (AHY): A bird that is in at least the second calendar year of its life. See hatch year.

AFTER SECOND YEAR (ASY): A bird that hatched out at least two years prior to the current one.

AHY: After Hatch Year.

ALBINO: A mutant form in which pigments are lacking. A true albino hummingbird has pink eyes, feet, and beak, and white feathers. A partial albino has some normal feathers and some white feathers. See leucistic.

Albizia julibrissin: Scientific name for Mimosa.

ALBUMIN: The so-called "white" of the egg. See also yolk.

ALPHA CODE: A system of abbreviations through which bird species are designated by four letters. The alpha code for Ruby-throated Hummingbird is RTHU.

ALTRICIAL: Born or hatched naked, blind, and helpless. Hummingbird babies are altricial. See also precocial.

ANIMALIA: The Kingdom in which the Ruby-throated Hummingbird is placed.

ANNA'S HUMMINGBIRD: See Hummingbird, Anna's.

ANNUAL: Yearly. In the case of plant life cycles, it means a plant lives for only one growing season and must germinate from seed each year. See also biennial and perennial.

ANTS: (Formicidae) Social insects that often are attracted in such large numbers to hummingbird feeders that the birds stay away.

APODIFORMES: The Order that includes hummingbirds and swifts. The name means "no feet" because long ago hummingbirds and swifts were thought not to have walking appendages.

APODIDAE: The Family that includes hummingbirds.

Aquilegia canadense: Scientific name for Red Columbine.

Archilochus: The Genus for the Ruby-throated Hummingbird (Archilochus colubris) and three other North American hummingbird species. Archilochus comes from two Greek words meaning "first in importance" and "an ambush."

Archilochus alexandri: Scientific name for Black-chinned Hummingbird.

Archilochus anna: Former scientific name for Anna's Anna's Hummingbird; now Calypte anna.

Archilochus calliope: Scientific name for Calliope Hummingbird.

Archilochus colubris: Scientific name for Ruby-throated Hummingbird.

Archilochus costae: Scientific name for Costa's Hummingbird.

ASY: After Second Year.

ASYMMETRICAL: Not symmetrical. Primary feathers in hummingbirds are curved and tapered and asymmetrical.

AVES: The Class in which all birds are placed.

AVIAN: Pertaining to birds.


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BAND: A thin piece of metal--usually aluminum--that is formed into a ring that is placed around a bird's leg. The band is inscribed with a unique number that allows banders to collect information about migration, longevity, site fidelity., and sizes of bird populations. (Outside of the U.S. and Canada, a band is usually called a "ring.")

BBL: Abbreviation for the federal Bird Banding Laboratory.

BEEBALM: (Monarda didyma) A red-flowering mint native to North America that attracts Ruby-throated Hummingbirds. It is herbaceous and perennial. Also called Oswego Tea.

BEE: See honeybee.

BELLY: The part of the bird just ahead of the base of the legs. In young male and all female Ruby-throated Hummingbirds this region is covered by white feathers; in adult males it is dusky green blending to white.

BIENNIAL: Occurring on a two-year basis. Biennial plants live two years, flower, and then die; they must be propagated from seed or cuttings. See annual and perennial.

BIRD BANDING LABORATORY (BBL): A federal unit--formerly with the U.S. Fish & Wildlife Service and now part of the U.S. Geological Survey--that oversees all bird banding (ringing) activities in the United States.

BLACK-CHINNED HUMMINGBIRD: See Hummingbird, Black-chinned.

BREAST: The region of a bird between the throat and the belly.

BREEDING RANGE: The geographic region or regions in which a species breeds. With regard to Ruby-throated Hummingbirds, breeding occurs in southern Canada and in the United States east of the Rocky Mountains.

BROOD: To protect young birds by sitting on them; also, nestful of young birds is a called a "brood."

BROOD PATCH: An area that develops on the belly and breast of birds--usually females--that are incubating eggs or brooding young. The area loses its feathers, becomes edematous, and shows increased vascularization--all of which help the adult bird transmit its body heat to eggs or chicks. In Ruby-throated Hummingbirds, the brood patch is not very pronounced.

BUCKEYE, RED: (Aesculus pavia) A native tree that attracts Ruby-throated Hummingbirds.

Buddleia davidii: Scientific name for Butterfly Bush.

BUSH, BUTTERFLY: (Buddleia davidii) An exotic woody shrub that attracts Ruby-throated Hummingbirds.

BUTT BAND: A bird band for which the ends merely butt together when placed around the bird's leg. Birds such as hawks and owls require "lock-on" bands with end flanges that fold over each other to prevent the birds from removing them.

BUTTERFLY BUSH: See Bush, Butterfly.

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CALCIUM: An element essential to formation of eggshell and bone in birds. Hummingbirds get calcium by eating small insects.

CALIPER: A device for making precise linear measurements. Used in Operation RubyThroat to determine the length of the wing chord of hummingbirds.

CALLIOPE HUMMINGBIRD: See Hummingbird, Calliope.

CALORIE: A unit of heat, usually thought of as the amount of energy per mass of a substance. Gram for gram, fat contains more calories than carbohydrates, even though the energy in carbohydrates is often more quickly released by metabolic processes.

Calypte anna: Scientific name for Anna's Hummingbird, formerly called Archilochus anna.

Campsis radicans: Scientific name for Creeper, Trumpet.

CANADA LILY: See Lily, Canada.

CARBOHYDRATE: An organic compound, consisting primarily of sugar or starch, that can be turned quickly into caloric energy. Hummingbirds get most of their carbohydrates from flower nectar or sugar water. See also fat and protein.

CARDINAL FLOWER: See Flower, Cardinal.

CATAWBA RHODODENDRON: See Rhododendron, Catawba.

CENTRAL AMERICA: For Operation RubyThroat, the Western Hemisphere countries south of Mexico in which the Ruby-throated Hummingbird regularly occurs: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama.

CHICK: A nestling, i.e., baby hummingbird still in the nest.

CHORD, WING: See wing chord.

CHORDATA: The Phylum in which the Ruby-throated Hummingbird is placed. It includes all animals that, in either embryonic or adult stages, have a notochord--a stiff rod that parallels the nerve chord. In vertebrates the notochord becomes the spinal column.

CIGAR PLANT: See Plant, Cigar.

CLASS: The third highest main level of classification. The Ruby-throated Hummingbird is in the Class called "Aves."

CLAVICLES: The "collarbones." In birds, the clavicles are fused at the tip to form a furcula, or "wishbone."

CLOACA: A bird's single opening for solid and liquid wastes, as well as for reproductive cells (eggs or sperm).

CLOACAL PROTUBERANCE: A swelling of the cloaca in male birds, caused by accumulation of sperm in a sac adjoining the cloaca; usually visible only in a bird captured for banding. In monomorphic species, the presence of a cloacal protuberance indicates the bird in hand is a male. The cloacal protuberance disappears during the non-breeding season when sperm are not being produced.

COEVOLUTION: The process by which, over time, organisms change due to adaptive pressures on each other. The long, narrow bill of the hummingbird is a co-evolved adaptation that allows it to feed on plants with long, tubular flowers that, in turn, are adapted (co-evolved) for fertilization by the hummingbirds that take their nectar. See evolution.

COLOR-MARK: A special marking placed on a bird in addition to its numbered aluminum band. In larger birds, color-marking can include plastic bands of different colors; these allow individual birds to be identified through binoculars without the need for recapture. In Operation RubyThroat, all Ruby-throated Hummingbirds banded at Hilton Pond Center for Piedmont Natural History in South Carolina are marked with a stripe of non-toxic GREEN dye across the upper breast or throat; birds banded at other locations by the Center's staff are marked with colors including blue, black, and brown.

colubris: The species name for the Ruby-throated Hummingbird (Archilochus colubris). The origin of the word "colubris" is not clear.

COLUMBINE, RED: A native North American perennial wildflower (Aquilegia canadense) that blooms in early and mid-spring and provides nectar for Ruby-throated Hummingbirds when there are few other plants blooming.

COMMON FOXGLOVE: See Foxglove, Common.

CONGENER: A member of the same Genus. The congener for the Ruby-throated Hummingbird (Archilochus colubris) is the Black-chinned Hummingbird (Archilochus alexandri).

CONTOUR FEATHER: See Feather, Contour.

COPULATION: Usually, the reproductive act by which sperm cells are transferred from a male to a female. In hummingbirds, the male has no intromittent structure (penis), so copulation consists of a quick touch of the tips of the cloacas of the two mates.

COSTA'S HUMMINGBIRD: See Hummingbird, Costa's.

COURTSHIP: Activities performed prior to actual mating. In Ruby-throated Hummingbirds, the male displays a noisy, aerobatic courtship flight that demonstrates his overall health to a prospective female.

COVERT: Feathers that cover the flight feathers (rectrices and remiges); e.g., primary coverts cover the bases of the primary wing feathers on a hummingbird and aid in streamlining.

CREEPER, TRUMPET: (Campsis radicans) A vine native to North America that attracts hummingbirds.

CROP: A thin-walled food reservoir that lies between the throat and the gizzard of a bird. Food is stored there temporarily and, in the case of female Ruby-throated Hummingbirds, the stored food can be regurgitated to feed young.

CROWN: The area on top of the head. In Ruby-throated Hummingbirds it is covered with green feathers, but sometimes appears yellow due to pollen deposits.

CULMEN: A standard measure used by bird banders; it is the straight-line measure of the top edge of the upper bill from its tip to the point where feathers begin to cover its base.

CUP: The depressed portion of a nest in which the eggs lie.

Cypress Vine: See Vine, Cypress.

Cuphea ignea: Scientific name for Cigar Plant.

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DDT: DichloroDiphenylTrochloroethane, a synthetic insecticide that, when passed along in the food chain, is known to interfere with calcium metabolism in birds, causing females to lay eggs with shells that are thin or absent. Although outlawed for use in the United States, DDT is still exported to countries where Ruby-throated Hummingbirds spend the winter.

Digitalis purpurea: Scientific name for Common Foxglove.

DIMORPHIC: Dissimilar in appearance. In the Ruby-throated Hummingbird, adult males have red gorgets and look different from females and young males--all of which have white throats--so they are said to be "dimorphic." See also monomorphic.

DISPERSAL: When an animal leaves an area and does not return. See also migration.

DOUBLE-BROOD: To rear a second set of young within a single breeding season, usually after a first brood has successfully fledged.

DOWN: Soft feathers that lie close to the skin surface of a bird and provide insulation.

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ECOLOGY: The study of interrelationships among organisms and between those organisms and the environment.

ECOTONE: An "edge" where two distinctly different habitats blend together. Ruby-throated Hummingbirds often nest in the edge between a wooded area and an open meadow or suburban yard; this ecotone usually contains plant representatives from the woods and the meadow, plus some distinctive species that may be found in edges but not in woods or meadow.

EDEMATOUS: Filled with fluid. When a brood patch develops in an incubating female, the fluid beneath her belly skin enhances the transmission of her body heat to the eggs or chicks.

EGG: The female's reproductive cell, or ovum, after it has been fertilized.

ENCOUNTER: See return and recovery.

ENDEMIC: Native to an area and, usually, breeding only within that area; see indigenous.

ETCHINGS: Tiny engraved marks on the upper bill of a recently fledged hummingbird. Over several months, the etchings wear off--or perhaps fill in and harden--and can be used to determine the approximate age of the hummingbird.

EVOLUTION: The process by which a species' descendants change over time from one distinct life form into another similar but different species. See also coevolution.

EYE RING: An area around the eye of a bird that is a different color from its surrounding feathers. An eye ring may be caused by the skin color of the eyelid, or by special feathers and may be "complete" (encircling the entire eye) or not. The Ruby-throated Hummingbird has a broken eye ring of white feathers along the posterior edge of the eye.

EXOTIC: Not native or indigenous. See also invasive.


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FAMILY: The fifth main level of classification. The Ruby-throated Hummingbird is in the Family called "Trochilidae."

FAT: A complex organic compound, usually ingested in the form of lipids, that is energy-rich but more slowly metabolized than carbohydrates. Tiny insects are the dietary source of fat for hummingbirds. See also protein.

FEATHER: A specialized structure that covers the body and is found only in birds. Feathers may be modified for insulation, flight, courtship, sun-shading, defense, and other functions.

FEATHER, CONTOUR: A feather that lies on the outside of the feather mass of a bird and defines its general shape. Contour feathers often aid in streamlining.

FEATHER, COVERT: See covert.

FEATHER, FLIGHT: A stiff feather in a bird's wing, usually the primary and secondary feathers.

FEATHER, PRIMARY: The long, asymmetrical wing feathers, attached to the fused phalanges and carpals of the birds "hand." In hummingbirds, primaries are the main feathers used for forward propulsion.

FEATHER, SECONDARY: The shorter, more symmetrical feathers on the wing that attach to the ulna (forearm bone) and lie between the primary feathers and the hummingbird's body. They are important in providing lift.

FEEDER: An artificial device--usually loaded with artificial nectar in the form of sugar water--that will attract hummingbirds.

FERTILE: Describing an ovum that has been fertilized. Also, when a female is capable of producing ova.

FERTILIZE: To unite sperm and ovum, resulting in a zygote that typically develops into a new organism.

FIDELITY: When mates have a stable pair-bond and do not breed with other individuals. In Ruby-throated Hummingbirds, males may mate with several females in a given breeding season. See also site fidelity.

FIGURE-8: The path traced by the flapping wing of the Ruby-throated Hummingbird that allows for--through changes in the shape of the wing's surface--forward, backward, and hovering flight.

FLANK: The side of a hummingbird, i.e., the area that lies underneath the wing when it is folded against the bird's body.

FLEDGE: Literally, to grow feathers. To leave the nest, usually with the ability to fly or run.

FLEDGLING: A baby hummingbird that has just left the nest (fledged). Nestlings are usually fully-grown when they fledge and are able to forage on their own.

FLIGHT FEATHER: See feather, flight.

FLOWER, CARDINAL: (Lobelia cardinalis) An annual native wildflower that attracts Ruby-throated Hummingbirds.

FORAGE: To search for food.

FOREIGN RECAPTURE: See Recapture, Foreign.

FOXGLOVE, COMMON: (Digitalis purpurea) An exotic annual that attracts Ruby-throated Hummingbirds.

FURCULA: The "wishbone." A structure unique to modern birds, formed by the fusion of the apexes of the two collarbones (clavicles).


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GAPE: The soft tissue at the corner of the mouth. In young Ruby-throated Hummingbirds it is yellow; in adults it is white or pinkish-white.

GENUS (pl. GENERA): The sixth main level of classification. The Ruby-throated Hummingbird (Archilochus colubris) has the genus name of Archilochus. When written with the species, the genus often is abbreviated, as in A. colubris. The first letter of the genus is capitalized, and the word is italicised (or underlined).

GIANT BLUE SAGE: See Sage, Giant Blue.

GIZZARD: The muscular stomach of a bird. In hummingbirds, it is where tiny insects are ground up into a digestible mush.

GONAD: An organ that produces reproductive cells. In male hummingbirds, the paired testes; in females, the functional left ovary.

GORGET: The throat feathers. In the adult male Ruby-throated Hummingbird they are an iridescent red; in females of any age they are white; in in young (Hatch Year) males and they also may be white or lightly streaked with black or green.


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HABITAT: Where something lives.

HALLUX: A bird's hind toe.

HARDINESS ZONE: See Plant Hardiness Zone.

HAREM: A social system in which a male hummingbird mates with several females. See polygamy and promiscuity.

HATCH YEAR (HY): A bird in the first calendar year of its life. See After Hatch Year.

HAWK, SHARP-SHINNED: (Accipiter striatus) A small hawk that preys on other birds, including hummingbirds.

HERBACEOUS: A general term for plants that lack a woody stem or trunk. Many hummingbird-attracting flowers are herbaceous and are either annual, biennial, or perennial,

Hibiscus syriacus: Scientific name for Rose of Sharon.

HILTON JR., BILL: Executive Director of Hilton Pond Center for Piedmont Natural History and creator of Operation RubyThroat: The Hummingbird Project.

HILTON POND CENTER FOR PIEDMONT NATURAL HISTORY: The parent organization that oversees Operation RubyThroat.

HOMEOTHERMIC: Able to produce one's own body heat and maintain it at a constant level regardless of ambient temperatures (common term is "warm-blooded").

HONEYBEES: (Apis mellifera) Social insects that sometimes visit hummingbird feeders in such large numbers that hummingbirds stay away.

HONEYSUCKLE, TRUMPET: (Campsis radicans) A perennial native vine that attracts Ruby-throated Hummingbirds.

HUMMINGBIRD: Any of 338 species of small birds in the Trochilidae. They are native only to the Western Hemisphere. Most are adapted for eating plant nectar, but all also eat insects as source of protein and carbohydrates.

HUMMINGBIRD, ANNA'S: (Calypte anna) This species breeds along the Pacific Coast, from Vancouver, British Columbia, to Baja, Mexico. It is seen very rarely in in fall migration in the eastern U.S.

HUMMINGBIRD, BLACK-CHINNED: (Archilochus alexandri) A congener of the Ruby-throated Hummingbird. Black-chins are the western counterpart of the ruby-throat, which they resemble. This species breeds in northern Mexico and in most of the U.S. west of the Rockies. Fall wanderers and wintering birds have appeared in many southern states.

HUMMINGBIRD, CALLIOPE: (Stellula calliope, formerly Archilochus calliope) This species breeds in western North American mountain regions from central British Columbia to extreme northern Arizona. It is seen very rarely in in fall migration in the eastern U.S.

HUMMINGBIRD, COSTA'S: (Calypte costae) This species breeds in the southwestern U.S. from Arizona to California, and in northwestern Mexico. Occasional fall wanderers appear as far east as Texas.

HUMMINGBIRD, RUBY-THROATED: (Archilochus colubris) The only hummingbird the breeds in the eastern United States and Canada. It overwinters primarily in Mexico and all seven Central American countries.

HUMMINGBIRD HABITAT: An area containing plants that produce nectar-bearing flowers attractive to hummingbirds AND plants such as trees and shrubs that provide places to nest and shelter from predators and the elements; water is typically present. The habitat may contain native or exotic plants, or both. A true Hummingbird Habitat meets all the day-to-day and reproductive needs of a hummingbird.

HUMMINGBIRD HOBNOB: An on-line discussion group through which people can share their hummingbird experiences and talk about Operation RubyThroat: The Hummingbird Project.

HY: Hatch Year.

HYPERPHAGIA: Significant increase in feeding activity, probably stimulated by photoperiod, in which hummingbirds eat large quantities of nectar and insects and put on fat stores prior to migration; marked by an increase in mass of 50-75%.


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Impatiens capensis: Scientific name for Spotted Jewelweed.

INCUBATE: To sit on eggs, keeping them warm through the transfer of body heat. In Ruby-throated Hummingbirds, only the female incubates.

INCUBATION PATCH: See brood patch.

INDIAN PINK: See Pink, Indian.

INDIGENOUS: Found naturally in an area. See also native.

INFERTILE: Unfertilized by sperm. Hummingbird females sometimes lay infertile eggs that cannot hatch. May also refer to a female unable to produce ova.

INSECTIVOROUS: To have the habit of eating insects.

INVASIVE: An exotic plant that is so successful that it crowds out native plant species.

Ipomoea quamoclit: Scientific name for Cypress Vine.

IRIDESCENT: Displaying a shift in color hues. In male Ruby-throated Hummingbirds, prismatic effects and scattering of light result in the gorget appearing either black or brilliant metallic red, depending on the angle from which the feathers are viewed.

IRIS: The pigmented portion of the eye. It is dark brown in the Ruby-throated Hummingbird but usually appears black. In an albino, the iris contains no pigment and red hemoglobin shows through from the blood-rich retina.


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JEWELWEED, SPOTTED: (Impatiens capensis) A native annual wildflower that attracts Ruby-throated Hummingbirds.

Justicia brandegeana: Scientific name for Shrimp Plant.

JUVENAL: Pre-adult. Juvenal plumage of the MALE Ruby-throated Hummingbird includes a white gorget that is replaced with red during the post-juvenal molt; females retain white throats throughout their lives.


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KACHINA: A doll or dancer used by Native Americans to explain messages sent by spirits to tribal elders. One type of kachina represents hummingbirds.

KEEL: The raised central portion of the breastbone of a bird to which the large flight muscles (pectorals) are attached.

KINGDOM: The highest level of biological classification. The Ruby-throated Hummingbird is in the kingdom called "Animalia."


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LANDSCAPING: Managing the terrain and plants of a location to improve its appearance or habitability.

LANTANA: (Lantana camara) An exotic plant that attracts Ruby-throated Hummingbirds.

Lantana camara: Scientific name for Lantana.

LEUCISTIC: Appearing at first to be an albino because of white or mostly white feathers, but having normally pigmented (dark) eyes, feet, and beak. Some leucistic hummingbirds may have tan or brown feathers.

LICHEN: An group of living things that each consist of a fungus and an alga living together symbiotically to form an entirely different organism. Female Ruby-throated Hummingbirds adorn their nests with bits of lichen that aid in camouflage.

LIFT: A condition, caused by air flowing over a wing, that allows a bird to rise in the air.

Lilium canadense: Scientific name for Canada Lily.

LILY, CANADA: (Lilium canadense) A tall native perennial plant that attracts Ruby-throated Hummingbirds.

LONGEVITY: How long something lives. When Ruby-throated Hummingbirds are banded and they return to their banding site in subsequent years, it is possible to calculate their ages. This is one of the many useful functions of banding in ornithological research.

Lobelia cardinalis: Scientific name for Cardinal Flower.

Lonicera sempervirens: Scientific name for Trumpet Honeysuckle.


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MACINTOSH: A reliable, user-friendly computer used to design, publish, and maintain the Operation RubyThroat Web site.

MASS: Technical term indicating how much matter an object consists of, often used when referring to an object's "weight."

MASTER PERMIT: A license issued by the federal Bird Banding Lab in Laurel, Maryland, USA, that allows individuals to capture and band wild birds for research and educational purposes.

MEMBRANE, NICTITATING: See nictitating membrane.

METABOLISM: All the processes by which an organism converts food to energy. Hummingbirds are said to have a "high metabolism" because they burn energy at a rapid rate.

METEOROLOGY: The study of weather.

MIGRATION: When an animal departs an area AND returns, usually in a later season or year. Different from dispersal, in which an animal leaves an area but does not return.

MIMOSA: (Albizia julibrissin) An exotic tree that attracts Ruby-throated Hummingbirds.

MIST NET: See net, mist.

MISTER: A device, usually hooked to a garden hose, that sprays a fine mist to provide hummingbirds with water for drinking and bathing.

MOLT: To lose feathers and then regrow them. In the Ruby-throated Hummingbirds, molting of the wing and tail feathers normally occurs on the wintering grounds. Some young (Hatch Year) males may begin to molt their white juvenal throat feathers in early fall before they migrate south; by the next spring Second Year males that return will all have a complete set of red throat feathers.

Monarda didyma: Scientific name for Beebalm or Oswego Tea.

MONOMORPHIC: Having the same appearance (morphology). In the Ruby-throated Hummingbird, adult females, young females, and young males all look alike and are said to be "monomorphic." See also dimorphic.

MORPHOLOGY: External appearance.

MORTALITY: Death. In groups, the rate of death.


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NATIVE: Found naturally in an area; indigenous. A native plant that is a natural nectar source for hummingbirds is adapted to the local habitat but may become choked out by invasive exotic plants. (See also endemic.)

NECTAR: A high-calorie, carbohydrate-rich, easily metabolized liquid produced by flowers. It is a major natural food for hummingbirds. (See also fat and protein.)

NEOTROPICAL: Pertaining to the New World tropics; i.e., the tropical regions of the continents and islands in the Western Hemisphere (including North, Central, and South America).

NEST: A structure--built by the female Ruby-throated Hummingbird from spiderwebs, plant parts, and lichen--in which the eggs are laid and chicks are raised.

NESTLING: A baby hummingbird still in the nest; also called a chick.

NET, MIST: A large (12m x 2m) net made of very fine string and used to snare flying birds for banding. Birds are taken from the mist net quickly after capture and are banded and released unharmed.

NICTITATING MEMBRANE: A bird's "third eyelid;" a semi-transparent membrane that covers the eye while a bird is flying, protecting it from drying out.

NORTH AMERICA: For Operation RubyThroat, the Western Hemisphere countries north of Central America in which the Ruby-throated Hummingbird regularly occurs: Canada, Mexico, and the United States.


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OIL GLAND: See uropygial gland.

OPERATION RUBYTHROAT: An international cross-disciplinary project in which students, teachers, and others collaborate to study the behavior and distribution of Ruby-throated Hummingbirds (Archilochus colubris). The project is an initiative of Hilton Pond Center for Piedmont Natural History.

ORDER: The fourth main level of classification. The Ruby-throated Hummingbirds is in the Order called "Apodiformes."

ORNITHOLOGY: The study of birds.

OSWEGO TEA: See Beebalm.

OSSICLES: The bones in a bird's eye; these form a ring that helps support and protect the bird's relatively large eyeball.

OVARY: The organ in a female that produces the ovum (unfertilized egg).

OVIDUCT: The tract within a female bird through which the ovum or egg passes.

OVUM (pl. OVA): An unfertilized egg still within the ovary or oviduct of a female bird.


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PECTORALS: The large paired flight muscles attached to the breastbone (keel) of a bird. In hummingbirds, the highly efficient pectoral muscles are laden with blood vessels and appear dark--unlike domesticated chickens and turkeys that have white breast muscles not suitable for long-distance flight.

PERENNIAL: In the case of plant life cycles, it refers to a plant that lives for several growing seasons. See also annual and biennial.

PENIS: The male intromittent organ that facilitates transfer of sperm. In hummingbirds, there is no penis, so copulation consists of the touching of the tips of the cloacas of the two mating birds. Sperm transfer is enhanced by the cloacal protuberance of the male.

PHENOLOGY: The study of change, especially with regard to changes that occur to due the seasons.

PHOTOPERIOD: The relative length of daylight to darkness. When days become increasingly short in autumn, it appears to stimulate hummingbirds to migrate south for the winter. Lengthening days in spring appear to be the cue to return to the breeding grounds.

PHYLUM: The second main level of classification. The Ruby-throated Hummingbird is in the Phylum called "Chordata."

PIN FEATHER: A new feather, just being produced by the feather follicle, that has not yet flattened out and is shaped like a pin. See quill.

PINEAPPLE SAGE: See Sage, Pineapple.

PINK, INDIAN: (Spigelia marilandica) A native wildflower that attracts Ruby-throated Hummingbirds.

PLANT, CIGAR: (Cuphea ignea) An exotic shrub that attracts Ruby-throated Hummingbirds.

PLANT, SHRIMP: (Justicia brandegeana) An exotic flower that attracts Ruby-throated Hummingbirds.

PLANT HARDINESS ZONE MAPS: Named climatic regions of North America as established by the United States Department of Agriculture (USDA) to indicate annual mean temperatures; these temperature ranges allow gardeners to select plants that are adapted for survival within the given temperature ranges.

PLUMAGE: Feathers.

POLLEN: The male reproductive cell of a plant. May serve as a minor source of protein for hummingbirds that pick up pollen when they visit flowers to get nectar.

POLYGAMY: A social system in which a male mates with more than one female. Many hummingbirds are polygamous and are sometimes said to have a "harem." See promiscuity.

POPULATION: All the members of one species that live in an area.

PRECOCIAL: Young birds that have down feathers and are able to run about when hatched. See also altricial.

PREDATOR: An animal that takes other animals as prey, usually killing and eating them.

PREEN: To groom feathers with the beak or feet. Often involves anointing feathers with oil from the uropygial gland.

PREY: An animal that is taken by a predator.

PRIMARY: See feather, primary.

PROMISCUITY: Mating with more than one individual without forming permanent bonds. Male Ruby-throated Hummingbirds may be promiscuous because their relationship with a female essentially ceases after mating. See also polygamy.

PROTEIN: An organic compound consisting of peptide-linked amino acids. Ingested by hummingbirds in the form of insects and pollen. Necessary to produce, build, and repair muscles and body organs. See also fat and carbohydrate.

PULL-STRING TRAP: See trap, pull-string.


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QUILL: A new feather just being produced by the feather follicle. When birds are undergoing molt and are partially covered by pin feathers, they are said to be "in quill."


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RAPTOR: Literally, "one who tears." In birds, a hawk or owl that preys upon or scavenges other animals and eats by tearing their flesh. The only raptor likely to prey on Ruby-throated Hummingbirds is the Sharp-shinned Hawk.

RECAPTURE, FOREIGN: A banded bird recaptured at a site away from where it was originally banded. Foreign recaptures provide information about dispersal, migration, and longevity.

RECOVERY: An encounter with a banded bird that is not alive, e.g., one that may have been killed when it flew into a window or vehicle, was taken but not eaten by a house cat, etc. Recoveries provide information about bird dispersal, longevity and migration. The number of any banded bird that is recovered should be reported to the Bird Banding Laboratory, toll-free at 1-800-327-BAND.

RECTRIX (pl. RECTRICES): Tail feather.

RED BUCKEYE: See Buckeye, Red.

RED COLUMBINE: See Columbine, Red.

REGURGITATE: To bring food back up from the digestive tract after swallowing it. Female hummingbirds regurgitate a slurry of nectar, pollen, and insects from their crops to feed their young.

REMIX (pl. REMIGES): Primary (wing) feather.

RETURN: An encounter with a banded bird that comes back to the same location where it was banded. Returns provide information about site fidelity and longevity. Returns are recorded by the bander but are not usually reported to the Bird banding Laboratory unless they indicate a new age record for a bird species.

RHODODENDRON, CATAWBA: (Rhododendron catawbiense) A native shrub that attracts Ruby-throated Hummingbirds.

Rhododendron catawbiense: See Rhododendron, Catawba.

RING: An international name for a bird band. Except in the United States, banders are usually called "ringers."

RIPARIAN: A habitat near water. Hummingbird nests are often found in riparian situations, i.e., near streams or ponds.

ROSE OF SHARON: (Hibiscus syriacus) An exotic shrub that attracts Ruby-throated Hummingbirds.

ROSEBAY: See Rhododenron, Catawba.

RTHU: Four-letter alpha code abbreviation for Ruby-throated Hummingbird.

RUBY-THROATED HUMMINGBIRD: See Hummingbird, Ruby-throated.

RUMP: The general area of a bird where the lower back and base of the tail join. The rump is sometimes marked with distinctive plumage. Hidden beneath the rump feathers is the uropygial gland.


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SAGE, GIANT BLUE: (Salvia guaranitica) An exotic perennial that attracts Ruby-throated Hummingbirds.

SAGE, PINEAPPLE: (Salvia elegans) An exotic perennial or annual that attracts Ruby-throated Hummingbirds.

Salvia elegans: Scientific name for Pineapple Sage.

Salvia guaranitica: Scientific name for Giant Blue Sage.

SAPSUCKER WELL: A series of holes in tree trunks made by any of several species of woodpeckers called sapsuckers (Sphyrapicus spp.), especially Yellow-bellied Sapsucker in the eastern U.S. Sapsuckers visit these holes, lap up the sap (a carbohydrate source) with their tongues, and eat insects (a fat and protein source) that are attracted to the sap. Sapsucker wells are important sources of food for hummingbirds, especially as they return in early spring when few flowers are in bloom and bearing nectar. Like sapsuckers, hummingbirds dine on both sap and insects.

SECONDARY: See feather, secondary.

SECOND YEAR: A bird in the year after the year it was hatched is a Second Year bird. The year begins on 1 January regardless of when the bird actually hatched.

SEMI-WOODY: Having stems that are relatively hard but that are likely to break during the winter after they are formed. See also woody and herbaceous.

SHARP-SHINNED HAWK: See Hawk, Sharp-shinned.

SHELL GLAND: A gland in the oviduct of a bird that secretes calcium that hardens around the yolk and white to form an eggshell. See also DDT.

SHELTER: One of the important components of hummingbird habitat. Shelter includes nesting spots and places to hide from predators and the elements. See also Landscaping.

SHRIMP PLANT: See Plant, Shrimp.

SHRUB: A woody or semi-woody perennial plant, usually with multiple main stems (or trunks) and a maximum height shorter than 5m at maturity.

SILKTREE: See Mimosa.

SITE FIDELITY: The degree to which an animal returns to a specific site, usually at the end of its migrational route.

SPECIES (pl. SPECIES): The lowest major level of classification. The Ruby-throated Hummingbird (Archilochus colubris) has the species name of colubris. The species name is written in all lower case letters and in italics (or underlined).

SPERM: The reproductive cell produced by the male.

Spigelia marilandica: Scientific name for Indian Pink.

SPOTTED JEWELWEED: See Jewelweed, Spotted.

SUBPERMITTEE: A person authorized by the U.S. federal Bird Banding Laboratory (BBL) to capture and band wild birds, but only under the guidance of a person holding a Master Permit.

SUBPHYLUM: A sublevel of the Phylum level of classification. The Ruby-throated Hummingbird is in the Subphylum called "Vertebrata."

SUGAR WATER: A standard mix of four parts water and one part table sugar that is placed in a hummingbird feeder as artificial food. The mix is high in carbohydrates but supplies no proteins or fats; hummingbird feeder mixes that contain minerals, vitamins, and proteins are commercially available but are relatively expensive compared to table sugar.

SUMMER: With regard to Ruby-throated Hummingbirds, the period from June through August during which the majority of reproduction occurs. See also winter.

SUMMER RANGE: The area of North America where the Ruby-throated Hummingbird spends the "summer" months (late March-September, with most breeding occurring June through August). See also winter range.

SY: Second Year.

SYMMETRICAL: Showing similar shape; half of a symmetrical shape is the mirror image of the other half. For example, tail feathers in hummingbirds are mostly symmetrical, while the longest wing feathers (primaries) are asymmetrical.


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TAXONOMY: The science of arranging organisms into groups, traditionally on similarity of structure but increasingly on genetic similarities.

TEA, OSWEGO: See Beebalm.

TERRITORY: An area, usually defended, in which an animal lives, feeds, and/or mates. A Ruby-throated Hummingbird will defend a feeding territory that includes flowering plants and/or a hummingbird feeder.

TESTIS (pl. TESTES): The male reproductive organ that produces sperm.

THROAT: Also called the gorget. The feathered "chin" area underneath the base of a hummingbird's beak, which is red in adult male Ruby-throated Hummingbirds.

TONGUE: The structure by which a hummingbird drinks nectar, using its brush-like tip to lap the fluid from flowers or artificial feeders. Hummingbirds do NOT use their beaks like a straw to suck up nectar.

TOTEM: A picture, carving, or other rendering of an animal (or plant) used by native Americans as a symbolic representation of an attribute or behavior. The hummingbird totem represents beauty, how to heal with flowers, laughter, and enjoyment of the environment.

TORPOR: An overnight lowering of body temperature. On cold nights, a Ruby-throated Hummingbird can lower its body temperature by about 15 degrees C (30 degrees F), conserving energy that would be required to maintain its normal temperature. The next morning, the hummingbird speeds up its metabolism and gets its body temperature back up to normal (40.5 degrees C or 105 degrees F) within a few minutes.

TRANS-GULF: Across the Gulf of Mexico. The migrational path of at least some Ruby-throated Hummingbirds, which breed in the U.S. and Canada and winter in Mexico and Central America. Migrational paths are not well-known in this species. Although some individuals are known to fly across the Gulf, others are suspected to go overland through Mexico, especially in fall migration.

TRAP, PULL-STRING: A device for capturing hummingbirds in which a feeder is hung within a trap. When a hummingbird enters the trap, the bander pulls a string to shut a trapdoor that captures the bird. The bird is removed, banded, and released unharmed.

TREE: A woody perennial plant, usually with a single main trunk and a height of more than 5m at maturity.

TRIPLE-BEAM BALANCE: A device used by some for determining the mass (weight) of hummingbirds.

TROCHILIDAE: The Family name for all hummingbirds. Trochilidae comes from a Greek word meaning "a small bird."

TRUMPET CREEPER: See Creeper, Trumpet.

TRUMPET HONEYSUCKLE: See Honeysuckle, Trumpet.

TRUNCATE: Having more or less squared tips, as in the secondary feathers of Ruby-throated Hummingbirds. See also acute.


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UNDERTAIL: The region beneath the tail feathers, as in undertail coverts.

UROPYGIAL GLAND: A skin gland on the upper surface of a bird's tail that produces oil used to maintain feathers.

USDA: United States Department of Agriculture. This agency developed the Plant Hardiness Zone Maps.


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VAGRANT: A wanderer that shows up in unexpected places. Several species of hummingbirds native to the southwestern United States appear as vagrants in the eastern U.S., especially in late fall and early winter.

VASCULARIZED: To have increased capillaries and, therefore, increased blood flow. In a female bird with a brood patch, the belly skin becomes vascularized, and the increased blood flow transmits her body heat more efficiently to eggs or young.

VERTEBRATA: The Subphylum in which the Ruby-throated Hummingbird is placed. A vertebrate is a chordate whose spinal nerve is protected by vertebrae of bone or cartilage (a "backbone").

VINE: A plant, either herbaceous, semi-woody, or woody, that grows horizontally unless supported by a vertical object such as a tree, post, or fence.

VINE, CYPRESS: (Ipomoea quamoclit) An exotic annual vine that attracts Ruby-throated Hummingbirds.


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WATER: An essential component of the hummingbird habitat. In the wild, hummingbirds drink dew and rain drops and bathe in small pockets of water in leaves; they will also bathe by flying repeatedly through mist formed by a misting nozzle attached to a garden hose. See also landscaping.

WHITE: The protein-rich layer that forms between the yolk and the shell of a bird egg. See albumin.

WING CHORD: A standard measure of bird wing length, from the bend of the bird's wrist to the tip of its longest primary feather.

WINTER: With regard to Ruby-throated Hummingbirds, period from October through mid-March when the birds are in Mexico or Central America. See also summer.

WINTER RANGE: The region where a Ruby-throated Hummingbird spends the winter months (approximately October through mid-March); this primarily includes Mexico and Central America. See also summer range.

WOODY: Having stems that are hard and long-lasting, usually covered by a layer of bark. See also herbaceous and semi-woody.


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Xenoornitholgy: The study of non-native birds.

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YELLOW JACKETS: Wasps that sometimes monopolize hummingbird feeders in dry summer weather.

YOLK: The intracellular food reserve of a fertilized egg. In birds, the yolk is yellow and becomes surrounded by the white.

YUCATAN: A peninsula of southern Mexico that juts into the Gulf of Mexico. It is suspected to be the location where most trans-gulf migrant Ruby-throated Hummingbirds first make landfall in autumn.


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