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Show SPEAKING SPEAIaNG SPEAK11'G SPEAK11G ' OF BIRDS . . . 0 . Theie's Theies The Thet , e's es ' really no blue or green in theIr theIrfeathers theirfeathers theirfeathers feathers , but sun rays , ram rant or a blue sky skycan skycan skycan can make our nesting friends colorfulas colorful as a apeacock apeacock apeacock peacock ! ! Prcpnrcd Prepnred Prepared by National Geographic Society SocietyWashington SocietyWashington SocietyWashington Washington D CWNU C-WNUService C WNUService CWNUServiceTHERE C -WNU WNU - WNU ServiceTHERE Service ServiceHHERE SocietyI I is no blue pIg pIgment pigment pigment HHERE THERE ment in m the feathers of ofbIrds ofbirds ofbirds bIrds , neither , wIth wIthrare withrare withrare rare exceptions ehceptIons is there any anygreen anygreen anygreen green The only pIgment pIgmentcolors pigmentcolors pigmentcolors colors in m ordinary ordmary bIrds birds'feathers birdsfeathers ' ' feathers are reds and yellows yellowsand yellowsand yellowsand and blacks and all the other othercolors othercolors othercolors colors are due either to a acombmatIon acombination acombination combmatIon combination of these or to tothe tothe tothe the superficial structure of ofthe ofthe ofthe the feathers overlying overlymg someother someother some other pIgment Blue feathers for example examplecontain , , con contain tam only brown or black black- blacktsh blackish - ish tsh pigment overlaid by a alayer alayer alayer layer of prismatic cells whIch whIchreflect whichreflect whichreflect reflect only blue light rays raysSometImes raysSometimes raysSometimes SometImes the structure IS ISthat isthat isthat that of minute mmute pits on the thesurface thesurface thesurface surface of the feathers When Whenthey Whenthey Whenthey they become filled with water dUTlng during duringa dUTlnga a rain they lose the r refractive refractivepower refractivepower retractivepower power and the birds apparently apparentlychange apparentlychange apparentlychange change from blue to white wrote as In the thetropIcal thetropical thetropical tropIcal swallow tanagersAgam tanagersAgain tanagers tanagersAgain Again Agam the blue color is due to tommute tominute tominute mmute minute air spaces in the superficial superficiallayer superficiallayer superficiallayer layer of cells lust just as the bluenessot bluenessof blueness of the sky is due to minute mmute dust dustpartIcles dustparticles dustparticles partIcles and the blueness of themills the them themilk m mills k on the boarding boardmg house table to tothe tothe tothe the minute mmute cream droplets So long longas longas longas as our blue birds remain between betweenus us and the source of light IJght , , , they are arenot arenot arenot not blue birds buds at all and therefore thereforemay thereforemay thereforemay may go unnot cedYellow cedYellow ced cedYellow Yellow birds are usually consp cu cuous cuous cuous ous because our eyes are very sen sensltIve sensitive sensitive sltIve sitive to yellow But many bIrds bIrdshave birdshave birdshave have a blue producing producmg structure structureoverlaId structureoverlaid structureoverlaid overlaId by a yellow pigment , , , so sothat sothat sothat that the combinat on sends green greenlght greenIght 1 lght ght to our e eies eyes ) es Then we say saythese saythese saythese these birds buds are green . . . . Wet the theback theback theback back of a parrot and it becomes becomesbrown becomesbrown becomesbrown brown or scratch the surface of one oneof oneof oneof of the green feathers with a kmfe knife kmfeand knifeand knifeand and a dark mark is left This Thls IS ISnot isnot isnot not because any green p gment is isscratched isscratched iascratched scratched off but because the yel yellow yellow yellow low and the prismatic cells have havebeen havebeen havebeen been removed and the dark layer layerbeneath layerbeneath layeibeneath beneath exposed But there seem to be many red redb redb redb b rds among these tanagers and andfinches andfinches andfinches redI I finches Why do we not see them themmore themmore themmore more often ' + Certainly Certamly we have no notrouble notrouble notrouble trouble seeing seemg a red traffic IJght- IJght light- light IJghtmdeed lightindeed light lightindeed - indeed mdeed most ot of them seem to be bethat bethat bethat that color when we are in m a hurry hurryThere hurryThere hurryThere There are some reds such as the theIridescent theiridescent theiridescent Iridescent throats t'1roats t1roats ' of the hummmg humming hummmgbIrds hummingbuds hummingbirds bIrds buds tor for which wroch the structure of the thefeathers thefeathers thefeathers , feathers is responsible But most mostreds mostreds mostreds i reds such as those of the tanagers tanagersand tanagersand tanagersand : and finches are due to pigment pigmentand pigmentand pigmentand and they register as red under all allIJght alllight alllight I IJght light conditions To be really efIec effec efIectlve effective efleclive tlve tive however the red must be exposed ex exposed exposed posed to direct sunlight sunllght . . . Should a scarlet tanager alight ahght m an mthe anthe mthe the middle of a suni sunl t lawn or a acardmal acardinal acardinal cardmal cardinal fly across the open space spacem spacean spacem m an a garden ether e a ther bird would at attract attract attract tract attention but most ol of the time timethey timethey timethey they are sitting slttmg among the shadows shadowsof of green leaves where they are arepoorly arepoorly arepoorly poorly lighted IJghted The sunlight is re reflected refleeted refleeted flected fleeted from the leaves more readIly readIlythan readilythan readilythan than from the birds especially s nee nce neeour nceour neeour our eyes are peculiarly pecul1arly sensitive to togreens togreens togreens togreensWinter greens greensWmter greensWinter Winter Wmter Markings Markmgs MarkingsDuring MarkingsDuring During Durmg the winter wmter many b rds rdshave rdshave rdshave have their conspicuous marks veIled veIledby veiledby veiledby by gray edges to the feathers These Theseedges Theseedges Theseedges edges break off during durmg the sprmg spring sprmgexposmg springexposing springexposing exposmg exposing the color underneath Themale The Themale Themale male house sparrow for example examplein in winter wmter seems to have only a nar narrow narrow narrow row Ime line of black on his throat , , , be because because because cause the rest of his black cravat IS ISconcealed isconcealed isconcealed concealed by the gray tips of the thefeathers thefeathers thefeathers feathers which break in m an AprilRed AprilRed April AprilRed Red finches display no such gray grayedges grayedges grayedges edges to the feathers But upon ex examm examen examin amm amen ng a feather with a lens one onewIll onewill onewill wIll find that the red pigment oc occurs occurs occurs curs only m an the main branches of ofthe ofthe ofthe the leaflike Ieafuke structure the parts partscalled partscalled partscalled called the shaftand shaft and the barbs whilethe whIlethe while ' the more minute mmute branches or barb I ules ales are gray As these barbuIes barbules barbuIeswear barbuleswear barbulewear * wear off the barbs with their color colorbecome colorbecome colorbecome become more exposed and the feath teeth teethers feathers feathers ers apparently get brighter Thus Thusthe Thusthe Thusthe the red finches ( the purple finchhouse finch finchhouse finchhouse house finchand finch and red redpolls polls ) > apparent apparently ly brighten as spring sprmg advancesThus advancesThus advances advancesThus Thus the summer tanager male maleremams maleremains maleremains remams remains red throughout the year yearand yearand yearand and so do the cardinal cardmal , , , the purple purplefinch purplefinch purplefinch finch the p ne grosbeak and the thecrossbllls thecrossbills thecrossbills crossbllls crossbills Tho The yellow evening gros gross grossbeak grosbeak > - beak never becomes gray like his hismate hismate hismate mate once he has acquired maturi maturf maturfty maturity maturity ty though the male mole goldfinch doesNo doesNo does doesNo No one has yet advanced a satIs sates satesfactory satIsfactory satisfactory factory explanation for these dIffer dIfferences differences differences ences in seasonal styles among the males but the inference mference is that the thefemales thefemales females are dully colored so as not notto notto notto to attract attention to the nest . . Usu Usually Usually Usually ally the brilliantly brilllantly colored males ma1es m an mthis anthis mthis this family never assist in m incubat incubating incubatlag incubating ing lag the eggs but even here there thereare thereare thereare are exceptions as in the ros rose- rose rosebreasted rose-breasted rose breasted - breasted and black headed gros grosbeaks grosbeaks grosbeaks beaks Males of these birds not notonly notonly notonly only sit on the eggs but even break breakall breakall breakall all rules of bird conduct by smgmg singing singingas smgmgas as they do soGrosbeak so soGrosbeak Grosbeak MortalityWhether Mortality MortalityWhether Whether because of the smging singing singingor smgingor or because ot of the bright colors of ofthe ofthe ofthe the incubating mcubatmg male or because of ofthe ofthe otthe the general fragility of the nest nestthere , , there is a relatively high nest mor mortaIJty mortality mortahty taIJty tality among the rose breasted gros grosbeaks grosbeaks grosbeaks beaks and some years very few 9 9a q a r 'llei llei ' " y . i is t ) ra raJ s , a t : J Wt Wtl Wt'lt l 'lt lt 'lta ' a "r r " { ; ' .r- .r . .rygi - ygi ) ) ' - : k k1 ' \ " \-1 1 \ ' - ZJ . , _ t ' , ! s ' ? .Y Y . < For their nest in the westa west , a pair of 0/ 0 0enlerprlSmg o f / fenterprising enterprising enlerprlSmg Los LosAngeles LosAngeles LosAngeles Angeles sparroics 6parrOlCS sparrows selectedan selected an anelectric anelectric electrIc witch sllJltch stretch box tchich IChlCh which the theO1ClIer theowner theowner O1ClIer owner immediately shut off to toprevent toprevent prevent electrocution . . Two TICO TICOfledghngs Twofledglings | fledglings fledghngs are shoicn sllOlIn shown : above , intheir In IntheIr intheir theIr noiel notel notelnest not el elnest nest young are reared Then the sp spe- spe species spe species - cies eles becomes scarce because gros grosbeaks grosbeaks grosbeaks beaks are not so persistent perS1stent about aboutrenesting aboutrenesting aboutrenesting renesting as are some other bIrdsThere birdsThere birds birdsThere There is no one place m an North NorthAmerica NorthAmerica NorthAmerica America where all 01 of o the b rds here herementIoned herementioned herementioned mentIoned can be found The pyrr pyrrhuloXla pyrrhuloxia pyrrhuloxia huloXla huloxia hepatic tanager beautiful beautifulbunt beautifulbunt beautifulbunt bunt ng rig and Sharpe s seedeater for forexample forexample forexample example are not found very far farnorth farnorth farnorth north of the IIIexlc tiexicdn Mexican n borderThe borderThe border ! The lazuli bunt ng black headed headedgrosbeak headedgrosbeak headedgrosbeak grosbeak western tanager rosy rosyfinch rosyfinch rosyfinch finch house finch green backed and andLawrence andLawrence andLawrence Lawrence s goldfinches goldflnches are birds of ofthe ofthe otthe the Pac Pacific lc coast and the Rocky Rockymount Rockymountain Rockymountain mount mountain am region while the rose rosebreasted rosebreasted rosebreasted breasted grosbeak scarlet tanager tanagerand tanagerand tanagerand and indigo mdlgo bunting buntmg are primarlly primarily primarllybIrds primarilybirds primarilybirds bIrds of the eastern United Umted StatesIt StatesIt States StatesIt It is difficult to explain why wby each eachspecIes eachspecies eachspecies specIes has a restricted summer summerhome summerhome summerhome home when it is tree free to come and go goas goas goas as it pleases and often migrates ex extenslvely extensively extensively tenslvely tensively It is still more dIfficult difficultto to ei e explain .plam plam > . plain how . this 1.lus 1lus whole group of ofb ofb ofb b rds got into mta North America orlgl origi orlglnally originally onginally nally Certain Certam of them such as the thetanagers thetanagers thetanagers tanagers the cardinals eardm.11s eardm11s . the blue bluerose bluerose bluerose rose breasted and black headed headedgrosbeaks headedgrosbeaks headedgrosbeaks grosbeaks and the buntings buntmgs have haveclose haveclose haveclose close relatives In Central and South SouthAmerIca SouthAmerica SouthAmerica AmerIca and none in the Old world worldHence worldHence worldHence Hence we feel that our specIes specIescame speciescame speciescame came originally orlgmally from the south . . p - Sq Sqp 4 4t 4a 4yp p c t yp p A"E AE A"EeA " a ? eA eAa eAxd a xd xdx xdM x M . , s se ' ' -e e - 7 4 7A a .J J A . pcture picture , 0/ 0 of 0evemng ofevening / evemng evening grosbea1.s grosbea1s grosbeaks . at Wlntt'fisl Wlnttfisl Whitefish ' . Lake , IU.ch IUch Mich . , ta1.en ta1en taken . with telescopIc len lens $ The camera luzs has auled aided auledman aidedman man manImmeasurably manimmeasurably Immeasurably In hIS study 0/ 0 of 0bird / bird birde life ' . /e e / . |