and from there the Horned extends KennKaufman on northto the edgeof thetundra, while the Eared is more a bird of lakes THEPRACTICED EYE in the interior of the arid west. 7•xtand Illustrations byKenn Kaufman From its northern breeding grounds,the HornedGrebe moves southmainly to coastalareas--in- cludingthe Atlantic Coast, where it is a common winter resident. In recent years,as Steve Stedman has pointed out [AmericanBirds46 (z): z75,Sum- Identifying mer x99z], the Horned Grebe has begunto winterregularly on reser- Monochrome Grebes voirsin the mid-south,up to 5oo miles north of the Gulf of Mexico. Still,I suspectthat the major part of inWinter the populationis on saltwater in winter. The Eared Grebe is a rare but an- nual visitor to the Atlantic Coast. Westof theMississippi it becomes a regularpassage bird on interiorlakes and reservoirs,and from the Great grebes,I think first of theirappear- Plains westward it is far more com- Typicalindividuals ancein winter, when their colorsand mon inland than the Horned Grebe. decorationsare muted and they can It is common in winter on the Pacific in basic plumage bemore challenging toidentify. Coast(and on westernreaches of the The HornedGrebe (Podiceps auri- Gulf of Mexico),and it maybe seen (fall and winter) tus)and Eared Grebe (Podiceps nigri- sideby sidewith the HornedGrebe are not hard collis)are both widespread in North in some California harbors. But the America (and in Eurasia as well). largestnumbers seem to winter on in- to separate. The Theydiffer from each other in many land waters. ways, includingshape, colors of Sowhen birders have problems in problemsare breedingplumage, timing of molt identification,these generally involve and migration,preferred wintering tryingto pickout Eared Grebes in the caused by all those habitatand breeding range, pattern east or Horned Grebes in the interior of thedowny young, et cetera. Their of the west. individuals that increasedsimilarity in winteris large- TypicalHorned Grebes in winter lyowing to default: only so much can have a very clean-cutappearance are not typical. bedone with a simple pattern of dark Theyshow a sharp line of contrastbe- aboveand light below. Still, typical tween black and white on the face, individualsin basicplumage (fall and andthe neck is cleanly white in front A SERIOUS INTEREST IN THE winter)are not hard to separate.The and blackish-grayin back.This is finepoints of birdidentification can problemsare caused by all those indi- quite a differencefrom the typical do oddthings to yourperceptions. I vidualsthat are not typical. winterEared Grebe pattern, featur- was reminded of this when I sat down The Eared Grebe is often consid- inga duskyface with a blurrywhitish to wdteabout grebes. The grebesof ered more of a "western" bird than "ear"patch, and a graywash over the the genusPodicepa show seasonal the Horned Grebe. Actually, in neck. If all individuals of the two changesin plumage;they sport tufts NorthAmerica the breedingranges speciesconformed to theseclassic and ruffsand brightcolors in the of both speciesare essentially west- patterns,there would be no problem breedingseason, and that is the time ern, and the main divisionis latitudi- at all. Unfortunately,there is quitea when they are most attractiveto nal: The Horned Grebe nests much bit of individual variation. Most bird human eyes(and, presumably,to farthernorth. The two speciesover- guidesdo not mention this, although each other). But when I think of lap extensivelyin southernCanada, the latest(•99 ¸) editionof Peterson's

Volume46, Number 5 1187 Figure1. EaredGrebes, to showsome of the variationin patternon the youngof the year. In the last five yearsI haveseen several birds like this. headand neckduring fall andwinter. The top twofigures show darker and Suchan individualwas photographed in Marylandby James Stasz several paler examplesthat might be seen in mid-winter.The lower le•t bird is still yearsago, and I blithelymisidentified the photoas representinga Horned in the processof moltinginto winter (basic) plumage. Timing of the molt Grebe(Birding 18: 288, October1986), althoughStasz himseti had seemsto bemore variable than in the HornedGrebe; by late fall, when identifiedit correctlyas an Eared.Notice that the eyeis dull yellowon this Hornedsare all essentiallyin winterplumage, some Eareds may still be bird--manyEared Grebes (perhaps mainly young birds) have odd eye molting.The lower right figure shows a trk:kyOctober bird, probably a colors,such as yellowor brown,in fall.

FieldGuide to lgOsternBirds gives a of uppermandible), with thedp of visible at a distance. goodillustration of variantsin both the lowermandible angling up to The plumagepattern of the face species.This variationis moderatein meet it. The Horned Grebe tends to andneck is variable in bothspecies, mid-winterbut may be extremein haveboth mandibles tapering more soany simplified description islikely latefall andearly winter, when the evenlyat the tip. The EaredGrebe to mislead.Especially in earlywinter, birdsare just arriving on their winter- typicallyswims with the bill held at a HornedGrebes may be very gray on inggrounds. slight downwardangle (Horned theupper neck and may have an ex- With a doseview, there is a differ- Grebeoften does also), so that any tensivedingy wash on theface. Eared encebetween the speciesin typical "upturned"effect of the bill itselfis Grebesat anytime of fall or winter bill shape.Some illustrations have cancelledout by the bird's posture. maylook surprisingly white-necked shown the Eared Grebe with a con- Bill color is anotherpoint that and clean-faced. Some Horneds spicuous,perky, upturned bill, which hasbeen overemphasized. In sum- showa big whitespot on the lores wouldbe a greatfield mark if it were mer, the Horned Grebe has a notice- (whichEared Grebes never have), but real.Unfortunately, the difference in ablewhitish tip on its dark bill, this is often faint and sometimes bill shapebetween the two species is while the Eared Grebe is black-billed lacking. subde,and partly bridged by varia- at that season.In winter, however, One area of the face does show a tionin bothspecies. In direct,close- bothspecies have fairly pale gray bills. consistentdifference, and that is the up comparison,the Earedtends to The Horned still often has a whitish regionimmediately behind the eye. havea straighter culmen (upper ridge tip on the bill, but this is hardly EaredGrebes, even if theylook rela-

11•- American Birds, Winter 1992 Figure2. HornedGrebes, to showsome of the variationin patternon the figureat lowerleft. Suchbirds still showthe sharpcutoff behind the eye headand neckduring fall and winter.The white spot on the loresis an typicalof the species,bnt even so, they are sometimes misidentified as excellentfield mark whenpresent, but it is faint or lackingon many EaredGrebes. I havenot seenindividuals as dingyas this in mid-winter,so individuals.In mid-to late-fall, whenthe speciesfirst arriveson the this maybe a characteristicof first-autumnbirds. winteringgrounds, some individuals can look quite "dirty-faced," like the tivelyclean black-and-white, show a to minute, asthe bird raisesor sleeks ing at trickywinter grebes should downward indentation of blackish or itsfeathers, but it usuallylooks differ- focuson headshape and on thepat- grayinto the white cheeks (Figure 0- ent from that of the Horned Grebe. ternon theface just behind the eye-- On the other hand, even on the The latter speciesshows a less with a specialstudy of bill shape,if dullestand dingiest Horned Grebes changeablehead shape. thebirds happen to be closeenough in basicplumage, there is a sharphor- Otheraspects of posturein both for that to be visible. izontalline of contrastbehind the eye grebescan vary widely, depending on Fall is the season when these two (Figurez). This difference gives each the birds'attitude (Figure 3)- The speciesare most likely to cause confu- a characteristicfacial expression, and neckmay be slouched or erect,and it sion.Differences in the averagetim- withpractice, it canbe seen at a great maylook thick or thindepending on ing of their southwardmigrations distance.Of course,a Horned Grebe how much the feathers are fluffed canprovide good clues. Over much moltingout of breedingplumage out.Both spedes usually float high in of the continent, the fall movement mayhave remnants of blackin the the water,but eithermay swim par- of EaredGrebes hits a peakin late cheekarea; some heavily molting tiallysubmerged at times. The Eared September,while Horned Grebes birdsmight not be identifiable. Grebesometimes looks more "fluffy" peakin earlyNovember, a full six For recognizingdistant grebes, at the back end, in the area where a weeks later. Even in those eastern re- shapeis alsoof criticalimportance, normal bird would have a tail. But gionswhere the Eared Grebe is con- andhead shape is the major thing to this,like other aspects of neckshape sideredrare, any purported "Horned notice. The head of the Eared Grebe andbody shape, is far too variable to Grebe" seen before mid-October seemsto varyin shapefrom minute be a useful field mark. Birders look- shouldbe scrutinized with great care.

Volume 46, Number 5-1189 Figure3. Sketchesof moment-to-momentchanges in postureand head the HornedGrebe, possihly indicating longer feathers on the foreheadand shape.Left four birds:Horned Grebes. The top and bottombirds are crownthat can be raisedand loweredto moredifferent positions. Notice relativelyalert; t•e t•ird fromthe tophas its feathers sleeked down just t•atthe bill is usuallyheld very slightly below horizontal in bot• species, beforea dive.Right five birds: Eared Grebes. The top bird is In a mildly andt•e differencein hill shapebetween t•e two is obscureor difficultto aggressiveposture; the bottombird is closeto the typicalsleeping judge at a distance. posture.Head shape appears to changemore in the EaredGrebe than in

Acknowledgments museumspecimens. I'm gratefulto Sdences,Philadelphia, for allowing The illustrations in this column were StephenM. Russelland ThomasR. meaccess to thosecollections. In my basedmainly on my field sketchesHueIs of the Universityof Arizona, eadierattempts to understandgrebe fromCalifornia, Arizona, Kansas, and Tucson,and to FrankB. Gill andMark variations, discussionswith Claudia New Jersey,but I alsostudied some B.Robbins of the Academy of Natural Wilds wereinvaluable. •

190.American Birds, Winter 1992