Antiphonal song Pair of birds intonating different parts of one common song.

Arid Dry.

Asynchronous hatching A clutch of eggs hatching one by one, on different days, as opposed to all together (synchronous hatching).

Auricular patch Colour patch of feathers above or near the ear (e.g. White-eared Bulbul).

Axilla The area where the underwing joins the body.

B

Bar Fine, transverse pattern, for example across the tail of a bird (e.g. Bar-tailed Godwit).

Bib Rounded breast patch from the chin downwards, e.g. House Sparrow).

Brood-parasitism The act of laying eggs in other birds' nests, e.g. by cuckoos.

C

Carpal joint The joint at the bend of a bird's wing, about half-way from the body to the tip.

Carunculation The presence of a naked, fleshy outgrowth, e.g. of skin around a bird's eye.

Casque Helmet-like horny structure on the head.

Cere Bare, fleshy skin surface at the top end of the bill, around the nostrils (e.g. Common Kestrel).

Chevrons V-shaped pattern, e.g. on the breasts of owls and immature raptors.

Class Taxonomic category. "Aves" (birds) are a class of animals.

Colour morph(ology) Different colourings within a species, irrespective of season, sex or age.

Coverts Smaller feathers at the base, protecting main feathers (wing or tail); there are greater, median and lesser wing coverts.

Crepuscular Appearing or flying in twilight conditions, at early dawn or late dusk (e.g. European Nightjar).

Crissum Undertail coverts and feathers around the vent of a bird.

Cryptic Camouflaged by an irregular colour pattern (e.g. the European Nightjar).

Culmen Ridge along the entire length or the top of the upper mandible of a bird's bill.

D

Dimorphism The existence of two types of morphology between males and females of one species. Morphological difference can, e.g., be different sizes (e.g. all raptors, where the females are larger than the males), different plumage patterns with identical colours or different colour patterns (e.g. Purple Sunbird).

Dispersal In birds' annual life cycle, the breeding season is followed by the "time of dispersal", when young birds are not fed by their parents any longer and have to go out in search of food, a partner and later, if applicable, their own territory.

Dispersive Moving away from the point of origin in various directions, often in response to changed external conditions. Birds of some species specialize in being able to travel long distances to find suitable habitats. These species are called "dispersive".

Diurnal (Active) at daytime.

Dorsal Relating to the top side; in birds this is the back, which is usually seen from behind. Showing the upperparts.

Down Wispy, soft feathers, e.g. of hatchlings, but also the the innermost, soft part of all other feathers.

E

Ear tuft Feathers near a bird's ear that can be, or are always, erected (e.g. Pallid Scops Owl).

Eclipse Usually dull, inconspicuous plumage assumed by birds at the anti-climax of their procreative cycle, i.e. outside their breeding season (see e.g. male Sanderling).

Egg-tooth Horny protrusion from the upper bill with which chicks of many species break their egg shells from inside to hatch.

Endemic Native to a certain area and found only there.

Extant Species found alive at the present day.

Extinct Species of which no living individuals exist any longer, i.e. which is no longer extant.

Eye-spot Feathers, or mark in a feather, that mimic an eye.

F

Facial disk A bird's face being formed like a disc (e.g. Pallid Scops Owl and other owls when viewed from straight in front).

Family (1) Adults with dependent birds; (2) taxonomic rank below an "order", above "genus". Several genera can belong to one taxonomic family, which will belong, usually along with other families, to an order.

"Fingers" Wide-spread primaries at the end of a bird's wing, especially in raptors (e.g. Egyptian Vulture).

Flank Part of a birds side, just below the bend of the folded wing.

Fledging Moulting from natal down into the first juvenile plumage.

Fledgling Bird leaving the nest, which usually happens at about the time of fledging, i.e. when a bird moults into a plumage that makes flight possible.

Foreneck The front side of the neck.

Frons The forehead, just above the upper bill (and cere). While inconspicuous in most species, some species have a frons with different colour.

Frontal shield Horny or fleshy forehead above the upper bill that is not part of the bill or nostrils.

G

Gape The corner of a bird's bill or beak; in dependent young birds that are still fed by their parents this part still has the same bright signal colour (yellow, orange or pink) as the inside of the bill. In most, but not all, adult birds the gape is the same colour as the rest of the bill.

Genus Taxonomic rank between "family" and "species".

Gestation This term is often used incorrectly when referring to the incubation period of birds' eggs. The term "gestation" is usually used only for mammals.

GISS See "jizz".

Gular Regarding the throat.

Gular fluttering Visible movement at the throat of a bird when breathing heavily or panting (e.g. Great Cormorant).

Gular pouch Flexible skin around the throat that can extend or be inflated.

H

Habitat The type of environment in which a bird lives, usually determined by a certain type of vegetation (in general determined by the availability of food, water and suitable nesting places).

Hackles (Sometimes spiny) foreneck feathers that are particularly long, creating the impression of a "beard".

Hatchling Bird that has just hatched from its egg. Here the term is used for birds that stay in the nest, but also for those that are precocial", i.e. which leave the nest immediately. It is often used only for "precocial" hatching birds, excluding so-called nestlings (birds that have just hatched, but stay in the nest under full parental care). See also "nestling".

Hepatic plumage is "liver-coloured", i.e. of a rufous, brownish tint.

Hood Feathers covering the head (e.g. Spur-winged Lapwing).

Hybridisation Interbreeding between different species, which leads to infertile offspring, called "hybrids". This is in contrast to interbreeding between different races of the same species, which leads to fertile offspring (and thereby gradations or mixtures in the characteristics of both races.

Hybrid zone Geographic area in which two races of the same species interbreed and in which, accordingly, gradations in the transition of the characteristics from one to the other can be seen.

Hyper-melanism Excess colour pigmentation (see also albinism and leucism).

I

Immature Birds that have not moulted into adult plumage yet, but do not have only juvenile plumage, i.e. the first plumage of contour (non-downy) feathers, either.

Incubation The process of keeping birds' eggs at a near constant temperature for a chick to develop in the egg is called incubation. The incubation period is the time it takes from the moment an egg is laid to the moment the chick hatches.

Iridescence Play of colours in a type of special feathers, with the colours changing depending on viewing angle (e.g. the speculi of ducks, wing patches of doves/pigeons and the body plumage of birds such as Glossy Ibises).

Iris The iris is the colored part of the eye that surrounds the pupil. It regulates the amount of light that enters the eye. In birds, irises can have diagnostic relevance. In some species, for example, males and females have differently coloured irises.

Irruption A sudden population explosion, e.g. by birds that, after breeding success, move from areas in the northern parts of their range when there is a scarcity of food.

Isolating mechanism Any kind of mechanism leading to the separation of parts of the population of a species (e.g. the expansion of a desert, cutting into two parts the range of a species), which can in the long run lead, by the process of evolution as a result of adaptation, to the creation of separate races and possibly separate species.

J

"Jizz" Derived from "GISS" (General Impression of Size and Shape), describes an overall impression of a bird, based on its various characteristics (a first impression caught at a glance).

Juvenile Bird with its first feather plumage, after moulting out of its natal down. A juvenile bird is often still under parental control or only just independent. It does not yet have its first non-breeding adult plumage.

K

Kleptoparasitism Stealing food from birds of other species; mostly found in pelagic species, such as e.g. Skuas/Jaegers

L

Lamellae Layers of thin membranes (made of stiff hairs) inside some species' bills for sieving food from water.

Lanceolate feathers - feathers shaped like the tip of a lance.

Leading edge Front edge (of a wing or flipper).

"Lean" vs. "fat", in terms of birds' body mass, refers to the habit of many (especially long-distance) migratory species to fatten up before their long and arduous journeys across the globe, dipping into their fat reserves along the way.

Leucism Deficiency of colour pigmentation (see also albinism and hyper-melanism).

Lores Area between bill and eye.

M

Malar stripe Cheek stripe. "Malar" refers to anything related to the cheek.

Mandible Upper or lower part of a bird's bill (a bird's equivalent to a human's jaws).

Mask Area around the eyes and part of the face (e.g. Green Bee-eater).

Migratory Regularly moving from one area to another and back, usually following the change of seasons.

Monotypic Attribute of a species of which only one form (race) exists (cf. "polytypic").

Morph This term replaces the previously used term "phase". It refers each type of variant in the plumage of bird species that exhibit more than one recurring morphology (e.g. different colour patterns in male and female, see "dimorphism").

N

Nape The back of a bird's neck.

Nestling A young bird in the nest (see also "hatchling").

Nictitating membrane Birds' third eyelid, a semi-translucent membrane that gives birds limited vision while protecting the eye (e.g. in flight or while feeding or striking prey).

Nocturnal (Active) At nighttime.

Nomadic Birds moving in an unpredictable, possibly erratic way, without a fixed pattern (such as a regular "migration") and without necessarily returning to their point of origin. For example, Asian Houbara are nomadic).

Nominate = name-giving. The nominate race of a species with more than one race is the one giving it its name.

Non-passerine Not similar to the House Sparrow (Passer domesticus), see explanation here.

Nuchal crest Crest at the nape of the neck.

Nuptial Of or regarding the process of breeding. During the breeding season, in addition to having breeding plumage, some bird species develop additional special characteristics for a short time period only (typically 1-2 weeks). While these features are present, they are said to have a nuptial flush.

O

Oil gland An oil-producing gland (also often called "preen gland" or "uropygial gland"), the secretion of which birds use to maintain and water-proof their feathers. The oil also has an anti-parasitic effect.

Operculum Cover ontop of the nostrils ("nares") at the base of some bird species' bill, in particular some species of doves or pigeons.

Orbit Socket in a bird's skull containing the eyeball.

Orbital ring Feathered or skinny ring surrounding the orbit (e.g. White-spectacled Bulbul).

Order Taxonomic rank between "class" and "family". The two major orders of birds are passerines and non-passerines.

Oscines True songbirds, see explanation here.

P

Palmate Foot with three webbed toes, while the fourth is free (usually small). For examples, see ducks and gulls.

Parasite In general, an organism that, in various possible ways, lives by exploiting another organism without giving anything in return. One such example of parasitic behaviour is stealing food from an animal of another species (see e.g. Parasitic Jaeger).

Partial migrant Species in which only part of the population migrates annually.

Passerine Similar in some ways to the House Sparrow (Passer domesticus), see explanation here.

Pelagic Oceanic; living far out at sea, generally beyond the reach of continental shelves (except while nesting).

Pellet Lump of regurgitated, undigested remains of prey (e.g. hairs, feathers, bones, etc.). Such behaviour is typical of, e.g., raptors, owls, gulls and corvids.

Plumage A bird's body cover of feathers.

Plume Long, wispy display feather (see e.g. African Sacred Ibis).

Polytypic Attribute of a species of which more than one form (race) exists. Cf. "monotypic".

Precocial Attribute of chicks that leave the nest very soon after hatching (e.g. Red-wattled Lapwing).

Preen gland An oil-producing gland (also often called "oil gland" or "uropygial gland"), the secretion of which birds use to maintain and water-proof their feathers. The oil also has an anti-parasitic effect.

Primaries Main (outermost) flight feathers on a bird's wing tip (see also "fingers").

R

Race Taxonomic rank below "species". A race (often also called "subspecies") is defined as a sub-group of a species with common characteristics. Interbreeding between different races of the same species will lead to fertile offspring (cf. "hybridisation").

Range The total area over which a certain species is observed, including all partial (sometimes non-contiguous) areas inhabited by the species.

Raptor Carnivorous bird that catches its prey with powerful talons and tears the prey apart with its strong beak.

Rectrix Main feather on a bird's tail.

Relict population Population with greatly reduced range or population that has been separated from the rest and is now isolated, in a reduced range.

Remex Primary or secondary feather in a bird's wing.

Rictal bristles Whisker-like stiff protrusions around the bill of many bird species (e.g. robins and other flycatchers; for a specific example see the page on the European Nightjar).

Roost (1) Sleeping place of a bird; (2) group of waders resting.

Rump Area between lower back and tail base.

S

Scapulars Feathers along the side of a bird's body, just above and overlapping the dorsal (trailing side) base of the wing.

Secondaries Central group of feathers on a bird's wing.

Shaft Main stem (rachis) of a feather.

Shoulder Dorsal lesser and median coverts (at the bend of the wing).

Size Total length of a bird from the tip of the bill to the tip of the tail.

Species Taxonomic rank below genus. In terms of bird breeding, the term "species" classifies all birds that can interbreed and have fertile offspring (cf. "hybridisation").

Speculum Iridescent patch on a bird's upper wing, usually most conspicuous in flight (see e.g. Rock Dove).

Spur Bony protrusion used as a weapon. Either on the leg (e.g. domestic roosters) or on the carpal joint of the wing (e.g. Red-wattled Lapwing).

Streamer Particularly long tail feather that protrudes well beyond the end of the regular tail feathers (e.g. Wire-tailed Swallow).

Striated Streaked; many juvenile birds are striated (e.g. Striolated Bunting).

Suboscine Also called semi-passerine - bird with the typical foothold of a passerine, but with a less-developed voicebox (syrinx). For an explanation see here.

Subspecies Altnernative term used for "race".

Sub-terminal "Short of the end" - usually referring to the location of a tail band just short of the tail's end.

Supercilium Eyebrow stripe above the eye (e.g. Rufous-tailed Scrub Robin).

Synchronous hatching A clutch of eggs hatching all within a very short period of time, as opposed to one by one (asynchronous hatching).

T

Talons Toenails. In particular often referring to the long, sharp and hooked claws of raptors and owls, used for killing and holding prey.

Tapetum Reflective layer at the back of the eyes of nocturnal animals used to capture very faint light. The layer that makes birds'/animals' eyes "shine" when illuminated at night.

Terminal At the end of...

Tertials (also Tertiaries) Innermost flight feathers on a bird's wing.

"TLC" Tender Loving Care = allopreening

Torpidity State of 'suspended animation' - similar to, but not as deep as, hibernation. Some bird species can reduce heartbeat and body temperature to conserve energy in adverse conditions (e.g. cold at nighttime). Swifts and nightjars (on other continents e.g. also hummingbirds) are capable of it. The Arabian species that is known to mostly use it is the Purple Sunbird.

Totipalmate Feet in which all four toes are webbed, as found, e.g., in all cormorants, gannets and boobies.

Trailing edge Rear edge (of a wing or flipper); for a trailing edge wing lining see e.g. the Sooty Gull.

U

Underparts All parts of a bird's body that are visible when the bird is hovering overhead; also called "ventrum". Therefore, when e.g. a raptor is seen from underneath, what one will see is called the ventral flight pattern.

Undulating Wavy.

Upperparts All parts of a bird's body that are visible when a hovering bird is seen from above; also called "dorsum". Therefore, when e.g. a raptor is seen from above, what one will see is called the dorsal flight pattern.

Uropygial gland An oil-producing gland (also often called "oil gland" or "preen gland"), the secretion of which birds use to maintain and water-proof their feathers. The oil also has an anti-parasitic effect.

V

Vagrant Bird found outside its usual range or habitat.

Vent Patch of feathers around a bird's cloaca (anus).

Ventral Relating to the bottom side; in a bird, when perched, this is the front. Showing the underparts.

Vermiculated Feathers with a dense, wavy pattern on them (e.g. Arabian Babbler).

W

Wattle Fleshy appendages hanging from the cheeks, throat or neck of a bird, often brightly coloured (e.g. Red-wattled Lapwing).

Whiffling is a commonly used term to describe large birds' behaviour when trying to lose height quickly to land, by alternatively side-slipping its wings.

Whirring refers to a sharp wing-whistling sound that some species of birds produce, mostly to shock attacking predators (e.g. the wing beats of Eurasian Collared Dove). Birds that use whirring usually have special wing feathers to produce a (temporarily) noisy wing beat.

Wing loading Ratio of body mass over total surface area of the wings, usually measured either in units of [g/cm²] (which we use here) or in [N/m²]. If, on the respective species pages, no reference is made to lean vs fat body mass, the value/s given are for lean weight (i.e., without fat reserves accumulated for long-distance migration).

Wingspan Distance from wingtip to wingtip, with both wings fully extended.

These pages are largely based on our own observations and those of our contributors. The structure of these bird pages is explained HERE. For more salient facts on any bird species please refer to a field guide.