KennKaufman THEPRACTICED EYE •xt andIllustrations byKenn Kaufman

WesternKingbird dentlrlCatlon

The Western Kingbird should be very easyto recognize.But kingbirds are of the tyrant flycatcherfamily, so of coursethey present hidden difficulties.

HENI WASEIGHTEEN I FELL in witha gangof Texas birders who had the tradition,initiated by the late EdgarKineaid, of giving bird-names to all their friends. In due coursethey named me the Western Kingbird.Nothing regal was implied bythat name, of course: this was dur- ing my hitch-hikingdays, and the WesternKingbird was a speciesthat wanderedwidely and was often foundalong roadsides. True enough.The WesternKing- bird (Tyrannusverticalis) is a wide- spreadbird, occupyingin summer the western 60% of the Lower 48 States,as well assubstantial chunks of southwestern Canada and northern Mexico.It isamong the most regular of the"western" strays along the At- Figure1. WesternKingbird (top) and Cassin'sKingbird (bottom), showing adults in lanticcoast every fall, and a fewusu- fresh plumage.

Volume 46, Number 2 - 323 Figure2. TropicalKingbird (left) and Western Kingbird (right). Seen alone, the Tropical (with its large head and long bill) gives the im- pressionof a biggerbird, but sideby side with Western it is seento heabout the samesize.

allywinter in southernFlorida. And hinda branch,or sidewaysto theob- on each side.Thus, the loss of two it doeslike roadsides--perching con- server,or even attached to a bird that featherscan remove this "diagnostic" spicuouslyon roadsidefences, or on issitting still as the observer zips by at mark. Even normal wear and abra- streetsidewires in suburbs,or evenin 60 miles an hour--it can be frustrat- sioncan reduce this white outer edge busydowntown areas. Widespread, ing to try to judge this one field mark. to obscurity.Western Kingbirds go common,favoring open areas, the In thisPracticedEyewe'11 lookat other throughtheir annualmolt in late WesternKingbird should be very differencesamong these birds. summer(adults) or after reaching the easyto recognize. WesternKingbird, the most wide- winteringgrounds (young birds); Butkingbirds are of thetyrant fly- ly familiarof thefour, is the best start- adultswith very worn tails might be catcherfamily, so of coursethey pre- ing point for comparisons.It's the seenany time after early summer, and sent hidden difficulties. Three other smallest-billedof our kingbirds, sug- those with the outer feathers absent kingbirdsin NorthAmerica are very gestinga specializationon smaller throughmolt arelikely in latesum- similar to the Western. These are (andmore abundant) insects, a menu mer.However, even birds in relatively Cassin'sKingbird (T. vocifirans),which would allow it to get by in freshplumage may accidentally lose TropicalKingbird ( T. melancholicus), built-up suburbsand wide-opensome of theirtail feathers at anytime andCouch's Kingbird ( T. couchit). spaces(induding treeless zones, where ofyear. Thestandard bird guide treatment it often builds its nest behind the A distinction not often mentioned is to emphasizethe tail patternsof crossbarofa telephone pole.) is thatWestern Kingbird has plainer thesekingbirds, and under ideal con- Thetail pattern of this species, fea- wings,season for season,than the ditionsthis is a goodapproach. But turingwhite outeredges, is well- otherspecies. In freshplumage, the when conditions are less than ideal known--butit's importantto note otherthree all haveconspicuous pale whenthe tail is heavilyworn, or that theseedges comprise only the edgingson thecoverts on thewing, moltinga fewfeathers, or hiddenbe- outer web of one outermost feather createda scalloped and striped effect,

324-American Birds, Summer 1992 Figure3. Taildetails. From left: tails of Tropical,Cassin's, and Western kingbirds, as seen from below, to showoverall tail shape,with oneouter rectrix detailed to showits shapeand pattern.These represent adult birds in freshplumage. Juveniles show a moretapered tip to eachrectrix. Note that the individualfeathers in the tail of Cassin'sKingbird are wider than in the otherspacies, no doubt con- tribetingto the bird'sbroad-tailed appearance; notice also that Cassin'sdoes have a paleouter edge on partof the tail.The fourth figure fromthe left representsa Western Kingbird tail in worncondition, with the whiteedges almost gone. This degree of wearis notexcep- tional,and migbt even be considered typical in lutesummer. The figure at rightrepresents a Western Kingbird that is infresh plumage buthas accidentally lost the outermost tail featheron each side. Such a patternwould be rare,but not impossible. These iliustrutions showwhy it wouldbe passibleto mistakea Westernfor oneof the otherkingbirds, even with a gondview of the tail pattern. whilethe edges of the coverts on West- (1)rannusj3rficatus) has a call very "whisker"area below the eyecan be ernKingbird are barely paler than the similarto this,but the otherking- noticedat a greatdistance. Another centers of these fehthers.This is sub- birds do not. pointthat may show up well,unless jectto the effects of wear, of course: in Cassin'sKingbird is a verycom- the bird is in worn plumage,is the wornplumage (generally after mid- mon breeder in the southwest, ex- patternedlook on thewing (created summeron adults), the pale edges may tendingnorth locally to southeasternby pale tips and edgesto all the beworn away enough to makeany of Montana and north-central Califor- coverts).Cassin's is a bulkier bird thesebirds look plain-winged. nia.Its rangethus overlapswidely than Western,with a thicker bill and The restof the plumageof West- with thatof WesternKingbird. The broader tail, and this differencebe- ernKingbird is relativelypale. Most twocan even be found nesting in the comesnoticeable with experience. of thehead is pale gray, setting off a samegroves of trees, but Cassin's gen- The specificname, voci•rans, is diffusedarker "mask"around the eye. erallyinhabits more wooded areas at well chosen. Cassin'shas a wide vari- The center of the throat is whitish slightlyhigher elevations. ety of calls,most with a loudand andthe upper breast is pale gray, but Cassin'sis darker about the head, roughquality. An abruptchibeew is thereis no sharpcontrast anywhere chest,and back than Western or the given frequentlyall year.Pairs on in this area.The upperback and otherkingbirds, but this can be hard nestingterritory often give an excit- scapularsare pale olive-graywhen to judgewithout a directcompari- ed-soundingkedeer k-edeer-kedeeer. fresh,losing much of the olive tone in son,because it seems to vary so much The "dawnsong," given at firstday- wornplumage. withlight conditions. It's easier to see light and occasionallylater, is very As with mostflycatchers, voice is areas of contrast. Whereas the dark notes,like berg-berg-Berg-BERG-BERGIO importantin identification.The "mask" of Western stands out on a Birdershearing this for the first time WesternKingbird's common call- palebackground, Cassin's shows litde in an Arizonapre-dawn have some- noteis a sharp, metallic k/p or kep. Its contrastbetween this area(lores and times confused it with the voice of moreelaborate calls are not soeasily ear-coverts)and the restof the head. the Buff-collaredNightjar (Capri- transcribed:itgives long, staccato, Thereis a strongcontrast, however, mulgusridgway•). sputtering,chattering series that are between the Cassin'swhite malar re- TropicalKingbird is very common oftendescribed as having a "bicker- gionand the dark gray area just be- and widespreadin the American ing" sound.Scissor-tailed Flycatcher hind it, and this contrastingwhite tropics(and is becomingmore so,

Volume 46, Number 2 - Figure4. Comparingthe bill shapes,face patterns,and uual headshapes of fou kingbirds.Upper left: WesternKingbird. Upper right: TropicalI•ngbird. Lowerleft: Cassin'sKingbird. Lower right: Couch's Kingbird. Tropical and Couch'sare extremelysimilar in all visual respects.Tropical is, ou average,a slightlysmaller bird but with a slightlylonger and thinner bill, andthis differencein ratio can impart a subtlydifferent look to their facial expressions,as shownhere. However,this wouldnot he a safe criterionfor identifyingeither one out of range.

unfortunately,as more forest is ferentspecies. Not until 1983did the Separatingthese two by sightis cleared). But north of Mexico it scientificcommunity formally agree. vastlymore difficult. Some average breedsregularly only at a fewpoints Separatingthe Tropical/Couch'sdifferences between the two, like the in southernArizona. Every fall a few complexfrom the other kingbirds is slighdygreener back of Couch's,are TropicalKingbirds stray up the Pacif- usuallystraightforward. Birds of this useless for field identification. icCoast--regularly to California,oc- pairare pale like theWestern King- Couch'sisa slightlylarger bird on av- casionallyto BritishColumbia, once bird, with an ill-defined darker erage,and to me it looksbulkier. It av- apparentlyto Alaska.Vagrants have "mask" but no other contrast on the eragesslightly shorter-billed than also reached the Atlantic Coast. Re- face.Unlike Western Kingbird, they Tropical,however, and this creates a centlyone or two pairs have been pre- are mostlyyellow on the chest,not subtlydifferent ratio of bill sizeto sent(and even nesting) in southern- gray,and more extensively white on overallsize, leading to a slightly differ- mostTexas, underlining a point that thethroat. They also show pale edg- entfacial expression. But I noticethis hadbeen apparent to Mexicanbird- ingson the wingcoverts, at leastin mainlyafter I alreadyknows which ersfor some time: Tropical Kingbird freshplumage. They are longer-billed species I'm seeing!Finding ironclad overlapsin breedingrange with its than either Cassin'sor Western. visual field marks for Couch's and identicaltwin, Couch's Kingbird. Tropicaland Couch's are most reli- Tropicalkingbirds is sdll an open Couch'sKingbird is mainly a spe- ably separatedby voice.All of the challengefor North American birders. cialtyof easternMexico, extending Tropical'scalls are variationson a north into Texas and south into thin,twittering trill, soundingmuch ACKNOWLEDGMENTS Guatemala and Belize. It is so similar thinner and more even than the ro- My illustrationsfor thiscolumn were visuallyto Tropical Kingbird that even bust sputteringof the Western. basedon my field sketchesand on somemuseum specimens of the two Couch'sKingbird whichis, in my specimensin the collectionof the cannotbe separated,and theywere experience,a morevocal bird than Departmentof Ecologyand Evolu- longtreated as races of onespecies. Tropical at most seasons--often gives tionaryBiology at the Universityof Theyhave strikingly different voices, asharp kip, similar to thatof Western. Arizonain Tucson.As always,I am however,and on this basisthe Texas It alsohas a metallicrolling breeyeer, grateful to StephenM. Russelland fieldornithologist L. IrbyDavis had anda rapidseries building to a crescen- Thomas R. HueIsfor allowing me ac- arguedfor years that they must be dif- do,pwit-puwit-puwit-paWITcheew. cess to that collection. '•

326-American Birds, Summer 1992