Birds – Part I VERTEBRATE ZOOLOGY (VZ Lecture23 – Spring 2012 Althoff - reference PJH Chapters 16-17) Scissortail flycatcher Bill Horn 2000

Distinguishing Features of Birds  __________ : no other vertebrates have these. Unique modification of the outerskin—clear advancement over scales  _______________: extremely lightweight… works in combination with feathers to accommodate flight  ________: toothless and covered with a horny sheath. More lightweight than jaws made of bone  _____________________: “richly provisioned” external eggs. Most elaborate reproductive cells of any animal

Distinguishing Features of Birds  __________________________: 6-11 times larger than those of like-sized reptiles. Helpful for processing sensory information, control of flight muscles  HIGHLY DEVELOPED ________________ & ______________: communication systems very advanced (sight and sound to the n-th degree). Navigation, depending on species, accomplished by using patterns of Earth’s magnetism, celestial cues, and maybe even polarized light.  ______________: adaptations permit allow metabolic demands of flight and temperature regulation

Classification & Diversity of Birds CLASS Aves ORDERS FAMILIES > 2,050 GENERA _________ SPECIES

Order with the most: Families  83 (next most is Charadriiformes… shorebirds…with 19) Genera  1,161 (next most is Apodiformes… swifts and hummingbirds… with 128) Species  ______ (next most is Apodiformes… with 422) Passeriformes (songbirds, perching birds, passerines) ____ of all bird species.

Classification & Diversity of Birds CLASS Aves SUPERORDERS ______________ “old jaw” 2 orders, 11 families, 63 species _____________ “new jaw” includes flightless birds

Paleognathae = old jaw Tinamiformes (47 species) Ratities (________ on their sternum) (16 species) A) Casuariiformes (emus & cassowaries) B) Rheiformes (rheas) C) Struthioniformes (ostriches)

Variable Yet Uniform…. Beaks and feet are specialized for different modes of feeding and locomotion Morphology of intestinal tract is related to dietary habits Wing shape reflects flight characteristics Bird morphology is ______ uniform than that of mammals  THIS UNIFORMITY IS BASICALLY A RESULT OF SPECIALIZATION OF BIRDS AS IT PERTAINS TO ___________.

Focus on Feathers Feathers develop from pits or follicles in the skin Except for a few species (ex. ratites, penguins), feathers are arranged in ________ or ________, which are separated by patches of unfeathered skin (the apteria). Total of ___ tracts ventral view dorsal view PJH Fig p436

Feather composition _____ of feather is composed of a specific type of _____________. This is a __________ that is closely related to the keratin that forms scales in lepidosaurs ~1% consists of lipids ~8% is H 2 0 Remainder: other proteins and pigments (including melanin) Feather color  produced by structural characters and pigments

Main Structural Features of Vaned Feather ________: anchor point to skin. Tubular in design. remains intact until molt ________: extends from calamus to end of feather. Bears closely spaced side branches called _______. _______: consists of barbs hooked together like velcro Calamus Rachis Vane

Barbs to Barbules Barbules branch from barbs….there are proximal barbules and distal barbules proximal barbule distal barbule

BARBULES proximal end distal end proximal barbule distal barbule

Ends of distal barbules bear hooks that insert in grooves in the proximal barbules of the adjacent barb rachis

_____________ barbule __________ barbule

Body-contour feather: BASE Different structure in some regions from a “typical” vaned feather Near base, barbs and barbules are flexible and barbules lack hooks  soft, loose, fluffy texture Called plumulaceous or downy Provides critical ________ __________ capability

Body-contour feather: non-BASE Portion above plumulaceous portion forms a tight surface called the VANE. Open vs. closed pennaceous portions This part of the feather is exposed to exterior surface of plumage Serves as airfoil, protects downy undercoat, sheds H 2 0, and reflects or absorbs solar radiation

Body-contour feather: non-BASE Barbules maintain the “closed” pennaceous portion of these feathers Arranged such that any physical disruption to the vane is easily corrected by the bird’s preening behavior “Realignment” (i.e., unruffling of feathers ) accomplished by bird drawing its slighlty separated bill over the vane

5 types of feathers CONTOUR FEATHERS SEMIPLUMES DOWN FEATHERS (several kinds) BRISTLES FILOPLUMES

contour feather down feather semiplume filoplume bristle

Contour feathers Includes typical body feathers and flight feathers Flight feathers include a) remiges (sing. remex)  wing feathers b) rectrices (sing. rectrix)  tail feathers Typically, large and stiff Mostly pennaceous contour feathers that are modified for flight Distal portions of outer primaries are usually abruptly tapered or notched…so that when wings are spread, there are slots or gaps at the tips  reducing drag. Also allows feather tips to twist as wings are flapped

Semiplumes Intermediate in structure between contour feathers and down feathers Combine a large rachis with entirely plumulaceous vanes Distinguish from down feathers by the rachis being longer than the longest barb Usually hidden beneath contour feathers Provide ________________ Provide “body” to help fill out contour of a bird’s body

Down Feathers Entirely plumulaceous Rachis is shorter than the longest barb or totally absent Provide thermal insulation Adult down Natal down…., present at hatching or very shortly (i.e., few days to week) usually precedes development of first contour feathers Uropygial gland down  at base of tail associated with sebaceous gland (oil to condition/waterproof feathers)

Down Feathers…con’t Powder down feathers  breakdown to produce extremely fine white powder composed of granules of _________. Shed into the general plumage, is not wettable, and therefore a form of waterproof dressing.

Bristles Stiff rachis and barbs only on the proximal portion…or none at all Usually found around base of the bill, around the eyes, as eyelashes…. Occasionally on the head or even between toes of some species Distal end of rachis is usually colored black or dark brown by melanin granules. The melanin adds strength as well as color May help some species “capture” flying insects

Collared nightjar - (found in Madagascar)

Filoplumes Fine, hairlike feathers with a few short barbs or barbules at the tip Serve as _________ structures that aid in the operation of other feathers….have numerous free nerve endings in their follicle walls  connect to pressure and vibrationreceptors around follicles  transmit info about the position and movement of contour feathers Thus impact _______, __________, _________ and ___________

___________ contour feather Brown, R.E. and M.R. Fedde Airflow sensors in the avian wing. Journal of Experimental Biology 179: [pdf posted on web page]