Vocal Copying in Lawrence's and Lesser Goldfinches

VOCAL COPYING IN LAWRENCE'S AND LESSER GOLDFINCHES

J.V. REMSEN, JR., Museum of Zoology, LouisianaState University,Baton Rouge, Louisiana 70893 KIMBALL GARRETT, Dept. of Biology, Universityof California, Los Angeles, California 90024 RICHARD A. ERICKSON, P.O. Box 657, Klamath, California 95548

With perhaps the exception of the Northern Mockingbird, no bird in the westernUnited Statescopies the vocalizationsof such a wide variety of bird specieswith such proficiencyas the Lawrence'sGoldfinch. Although this vocal "mimicry" was long ago describedby Dawson (1923), subsequent workers have apparentlyfailed to notice this strikingfeature of Lawrence's Goldfinch vocalizations. Linsdale (1968) cited numerous references concerning descriptionsof the song, none of which mentioned imitation. Coutlee (1971) studiedin detail the vocalizationsof this species,yet did not realizethat the elaboratesong is composedprimarily of notescopied from other birds'vocalizations. Concerning the vocalizationsof thisspecies, Lesser Goldfinch, and American Goldfinch, Coutlee (1971:561) stated "these... are probablyamong the longestand most varied of passerinesongs (excluding, of course, birds which mimic other songs)." Lawrence's Goldfinch was not included in Dobkin's (1979) extensive list of birds known to copy other species. From 1973 to 1980 we made notes on the compositionof songsof individual Lawrence'sand Lessergoldfinches with respectto speciesimitated. Our field experience has involved birds on the wintering grounds as well as breedingbirds, and has spanned most of the range of Lawrence'sGoldfinch and much of the northernand westernrange of LesserGoldfinch. We have no tape-recordingsto document our case for interspecificcopying, but we feel secure in our contentionsin that the imitationsare very obvious to anyone familiar with the vocalizationsof California birds. The cadence, frequency and duration of Lawrence'sGoldfinch song is well describedby Coutlee (1971). However, most, if not all, notescompris- ing the song are obviousimitations of call notes of other species.In Table 1 we present a list of all bird species(plus one frog) whose calls we have recognizedin Lawrence'sand Lessergoldfinch songs. We are not certain if the Lawrence'sGoldfinch has notes or phraseswithin its song that are truly its own, exceptfor itscharacteristic flight call, which is frequentlyused as a note in the song. Species whose vocalizations are incorporated most frequently into Lawrence'sGoldfinch song are those with loud, distinctiveor simple calls. These vocalizationsare usuallyprominent sounds in goldfinchhabitat. No other correlates,taxonomic or ecological,can be discernedfrom the list of speciescopied. Many of the speciesfrom Table 1 are alsofrequently imitated by the Northern Mockingbirdand the European Starling ($turnus vulgaris) (pers. obs.), the two other speciesin California most noted for their vocal copying. Western Birds 13: 29-33, 1982 29 VOCAL COPYING IN GOLDFINCHES

The quality of Lawrence'sGoldfinch vocal appropriationsis suchthat in- dividualappropriated calls, if given by themselves,would be virtuallyin- distinguishablefrom model species,although sound spectrograms of course mightreveal stronger differences. The precisionof imitationis suchthat calls of closely-related,similar-sounding species/subspecies can be clearly distinguished,e.g. "Audubon's"from "Myrtle" Warbler and Hairy from Downy Woodpecker. Vocal copyingin the Lawrence'sGoldfinch falls into Dobkin's(1979) categoryof "vocalappropriation." We feel that it is highlyunlikely that the copied vocalizationsfunction in interspecificcontexts, i.e., either "vocal mimicry"or "vocalconvergence or non-divergence"(sensu Dobkin). Since Lawrence'sGoldfinch frequently copies the flight callsof all three North American congeners,"vocal convergence"is possiblebut evidence is lacking. Although we have no convincingexplanation for the function of vocal appropriationin the Lawrence'sGoldfinch, we arguethat it almostcertainly has nothingto do with negativeeffects on model species,i.e., exclusionof competitors,as proposedby Cody (1974:248) for vocal copying by the Northern Mockingbird and European Starling. This explanation is unsatifactoryfor such casesof vocal copyingfor three reasons:(1) the ecologicalrange of speciescopied is extremelybroad, with no tendenciesfor favoringpotential close competitors; (2) sincemost copied vocalizationsare callsor song segmentsrather than completesongs, it is unclear what effect these would have on target species--attraction because of territorial aggressionor "curiosity"is perhaps more likely than repulsion; anti (3) EuropeanStarlings (and goldfinches) have type "B" territoriesused primarily for nestingrather than feedingand thus modelsshould be limitedto nest-site competitors.(They are not.) Furthermore, in the case of the goldfinches, vocalcopying is prominent among non-breeding, presumably non-territorial, winterbirds. Mainly for lackof plausiblealternatives, we favor an explanation concerningan expansion of repertoire size as an index of fitness (Howard 1974). Much of what we say concerningvocal appropriationsin the Lawrence's Goldfinchalso applies to the LesserGoldfinch. Vocal copyingin the Lesser Goldfinchwas also describedby Dawson (1923); in Table 1 we list species whose vocalizationswe have heard "appropriated"by LesserGoldfinches. Most differencesin model speciesbetween the two goldfinchesare due to slightdifferences in their habitatpreferences, with LesserGoldfinch favoring more mesicareas. The LesserGoldfinch occupies a rather wide geographical range, and the speciescopied vary with locality. An individual at Sarita, KlebergCo., Texas, faithfullycopied the "wee-bee" song segmentof the EasternPhoebe ($ayornisphoebe, 6 May 1980); we have never heard this speciescopied in California (where it is rare visitor). A LesserGoldfinch at Patagonia, Santa Cruz Co., Arizona, incorporatedthe calls of the Gila Woodpecker(fi4elanerpes uropygialis, 26 June 1976) into its song;the Gila Woodpecker does not occur in most of the California range of the Lesser Goldfinch,and we have not heard it copiedin that state.This geographical variation further suggeststhe importance of prominent environmental soundsas incorporatedelements in the song of the LesserGoldfinch. The

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Table 1. Specieswhose vocalizations are copiedby Lawrence'sand/or Lessergold- finches.

Lawrence's Lesser American Kestrel (Fal½osparverius) X • X California Quail (Callipepla ½alifomica) X Gambel's Quail (Callipeplagambelii) X Killdeer (Charadrius vo½iferus) X Spotted Sandpiper (Actirismacularia) X Greater Yellowlegs(Tringa melanoleuca) X Northern Flicker (Colapresauratus) X X 1 Acorn Woodpecker (Melanerpesfor- mi½ivorus) X Hairy Woodpecker(Pi½oides villosus) X 3 Downy Woodpecker (Pi½oides pubescens) Ladder-backedWoodpecker (Picoides scalaris) X • Nuttall's Woodpecker (Picoidesnuttallii) X Western Kingbird (Tyrannus verticalis) X Cassin'sKingbird (Tyrannus vociferans) X Ash-throatedFlycatcher (Myiarchus cinerascens) X Black Phoebe ($ayornisnigricans) X Western Wood-Pewee (Contopus sor- didulus) X 1 WesternFlycatcher (Empidonax difficilis) Violet-greenSwallow (Tachycineta thalassina) X Barn Swallow (Hitundo rustlea) X Scrub Jay (Aphelo½oma½oerulescens) X Plain Titmouse (,Parus•'nornatus) X 2 Xl.2 Verdin (Auriparusflaviceps) X • White-breastedNuthatch (Sitta ½arolinensis) X Bewick's Wren (Thryomanes bewickii) X • House Wren (Troglodytesaedon) X Rock Wren (Salpinctesobsoletus) X •'• Canyon Wren (Catherpesmexicanus) X Northern Mockingbird(Mimus poly- glottos) X American Robin (Turdus migratorius) X • X 1 HermitThrush (Catharusguttatus) X x Western Bluebird (Sialia mexicana) x • Blue-grayGnatcatcher (Poliopt•la caerulea) X Ruby-crownedKinglet (Regulus calen- dula) X Water Pipit (Antbus spinoletta) X Cedar Waxwing (Bombycillacedrorum) X Phainopep]a(Phainopepla nitens) X Solitary Vireo (Vireo solitarius) X Yellow-rumped Warbler (Myrtle) (Den- droica c. coronata)

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Table 1 (Cont.) Lawrence's Lesser Yellow-rumpedWarbler (Audubon's) (D.c. auduboni) X X Western Meadowlark ($turnella neglecta) X Northern Oriole (Bullock's) (Icterus galbula) X Brown-headed Cowbird (iVlolotl•rusater) X House Sparrow (Passerdomesticus) X 1 House Finch (Carpodacusmexicanus) X 2 X 1.2 Pine Siskin (Carduelis pinus) X x American Goldfinch (Carduelis tristis) X x' Lesser Goldfinch (Carduelis psaltria) Lawrence's Goldfinch (Carduelis lawrencei) Brown Towbee (Pipilofuscus) X Rufous-crownedSparrow (Airnopl•ila ruficeps) X Dark-eyed Junco (junco hyernalis) PacificTreefrog (Hyla regilla) X

'Heard in over 50% of individuals 2Songsegments appropriated as well as calls 3Two or more types of callsappropriated

Note: This table is basedon field experienceof the authorswith approximately30 in- dividualC. lawrenceiand 25 C. psaltria;about 60% of the individualsof bothspecies were non-breedingbirds on theirwintering grounds. See Dawson(1923) for an addi- tional listingof speciesimitated.

majordifference between imitations made by Lesserand Lawrence'sgold- finchesis that in the LesserGoldfinch, a lower percentageof songsyllables canbe readilyidentified as appropriatedfrom other species, with many song sequencesdevoid of any appropriatedmaterial. We have never heard the other two California members of the genus, American Goldfinch and Pine Siskin, copy other species,despite their proficiencyat intraspecificimitation (Mundinger 1979). Therambling song of the Pine Siskinis quitesimilar in form to that of the Lawrence'sand Lesser goldfinches,but appearsto containno appropriatedmaterial, containing insteada varietyof PineSiskin call notes. The formand qualityof American Goldfinchvocalizations are quite distinctfrom those of North American congeners,and apparentlydo not containappropriated material. We thank John W. Hardy, Theodore A. Parker, III, Thomas S. Schulenbergand PeterStettenheim for helpfulcomments on the manuscript.

LITERATURE CITED Cody, M.L. 1974. Competitionand the structureof bird communities.Monogr. Popul. Biol. 7. PrincetonUniv. Press,Princeton, NJ. Coutlee,EL. 1971. Vocalizationsin the genusSpinus. Anim. Behav. 19:556-565.

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Dawson.W.L. 1923. The birdsof California,Vol. I. SouthMoulton, Los Angeles. Dobkin, D.S. 1979. Functionaland evolutionaryrelationships of vocal copying phenomenain birds.Z. Tierpsychol.50:348-363. Howard. R.D. 1974. The influenceof sexualselection and inter-specificcompetition on Mockingbirdsong. Evolution 28:428-438. Linsdale,J.M. 1968. Spinuslawrencei (Cassin). Lawrence's Goldfinch. In O.L. Austin,Jr. ed. Life historiesof North Americancardinals, grosbeaks, buntings, towhees.finches. sparrows, and allies. Part 1• Bull.U.S. Natl. Mus.No. 237 Mundinger,P.C. 1979.Call learning in theCarduelinae: ethological and systematic considerations.Syst. Zool. 28:270-283.

Accepted 19 August 1951

Lawrence's Goldfinch Sketch by Cameron Barrows