The Function of Singing in Female Black-Headed Grosbeaks (Pheucticus Melanocephalus): Family-Group Maintenance

THE FUNCTION OF SINGING IN FEMALE BLACK-HEADED GROSBEAKS (PHE UCTICU$ MELANOCEPHAL US): FAMILY-GROUP MAINTENANCE

GARY RITCHISON 1 Departmentof Biology,UMC 53, Utah StateUniversity, Logan, Utah 84322USA

ABSTRACT.--Theresponses of young Black-headedGrosbeaks (Pheucticus melanocephalus) to playbackof the songsof parentsand strangerswere examined.I found that young grosbeaks moved about more, called more, and were more often oriented toward speakers in responseto parental song(both male and female) than in responseto the songsof strangers. I suggest that such a responseis part of a system used by Black-headedGrosbeaks to maintain family groups after the young fledge. In this system, an adult with food, but unawareof the locationof its young, singsto elicit beggingfrom its young. The parent bird is then able to locateand feed its young. Received31 August1981, accepted26 May 1982.

AMONG passerines, song is typically the and Hooker 1969, Bertram 1970, Payne 1971). function of the male. There is also much evi- Concerninginstances of female singing other dence,however, of regular, occasional,and ar- than antiphonalsinging or duetting, Kern and tificially inducedsong by females.It has long King (1972)have suggesteda number of func- been recognized,for instance,that femalesof tions, including stimulating the breeding ac- many speciescan be induced to sing by injec- tivities of the male. Nottebohm (1975) sug- tion of testosterone (Baldwin et al. 1940, Kern gestedthat singingby femalesmay influence and King 1972). There are also many reports of a bird's socializationand choiceof partner and, speciesin which the female sings only in ex- in some cases, aid in territorial defense. ceptionalcases, e.g. the WesternMeadowlark Among the speciesof birds in which singing (Sturnellaneglecta; Lanyon 1957), Indigo Bun- by females has been reported is the Black- ting (Passerinacyanea; Nolan 1958), Song Spar- headed Grosbeak (Pheucticusmelanocephalus; row (Melospizamelodia; Van Tyne and Berger see Fig. 1). Weston (1947), in a general study 1976), EasternPhoebe (Sayornisphoebe; Smith of the breeding behavior of the grosbeak,re- 1969), Eastern Bluebird (Sialia sialis; Morton et ported that femalessang "while incubatingor al. 1978), and White-crowned Sparrow (Zono- brooding, usuallyas the male comesto take his trichialeucophrys; Kern and King 1972).In oth- placeon the eggsor young. Severaltimes dur- er species,singing appears to be a regularfea- ing nest-building, the female uttered songsin ture of femalebehavior, i.e. many specieshave the vicinity of the nest and always in the pres- beenreported in which femalescommonly sing ence of the male. The female will also occa- in a variety of situations (Table 1). sionally sing while foraging in the peripheral Despite these many observations, the sig- foliageof trees,but only when the male is close nificance of singing in females remains ob- by." Armstrong(1963) statedthat singing by scure. Possible functions, however, have been females tends to be characteristic of cardueline postulated. Armstrong (1963) suggestedthat finches.Van Tyne and Berger(1976: 249), in a antiphonal singing is a "means whereby con- general discussionof female song, suggested tact, rapport, and the social bond are main- that the songs of the female Black-headed tained." Duetting is believed to be important Grosbeakare nearly as elaborateas thoseof the in the synchronizationof breeding behavior male. and in the reinforcementof the pair bond (e.g. Despite these observations, the function of Thorpe and North 1965, Thorpe 1966, Hooker female songin the Black-headedGrosbeak, as in other species,is unclear. The present study 1 Present address: Department of Biological Sci- is an attempt to ascertainthe function(s) of this ences, Eastern Kentucky University, Richmond, song. The initial year of this 2-yr study was Kentucky 40475 USA. devoted to extensive field observation and re-

105 The Auk 100: 105-116. January 1983 106 GARY RITCHISON [Auk, Vol. 100

TABLE1. Reportsof singing in femalesamong various arian species.

Situations in which Suggested female singsa function(s) a Species NB NR I B FY TD PB-M C F-GM Source

Greenshank Simms 1958 Tringa nebularia European Nightjar X Selous 1905 Caprimulguseuropaeus Gray-capped Flycatcher X Skutch 1953 Myiozetetesgranadensis LoggerheadShrike X Armstrong 1963 Lanius ludovicianus European Dipper X X Van Tyne and Berger Cinclus cinclus 1976 American Dipper X X Bakus 1959a, b Cinclus mexicanus House Wren X X X Armstrong 1955 Troglodytesaedon Wrentit X Armstrong 1963 Chamaeafasciata Blue Wren X Robinson 1949 Malurus cyaneus ParadiseFlycatcher X Moreau 1949 Terpsiphoneviridis Elepaio X X X X Conant 1977 Chasiempissandwichensis Willie Wagtail X Robinson 1949 Rhipiduraleucophrys White-crowned Sparrow X X Blanchard 1941, Kern Zonotrichialeucophrys and King 1972 Grasshopper Sparrow X X X Smith 1959 Ammodramus savannarum Variable Seedeater X Gross 1952 Sporaphilaaurita Cuban Grassquit X Baptista 1978 Tiaris canora Gray Catbird X Palmer 1949 Dumetella carolinensis Mockingbird X Armstrong 1963 Mimus polyglottos Brown Thrasher X X X Thomas 1952 Toxostomarufum European Robin X Lack 1939, 1943 Erithacus rubecula Eastem Bluebird X Thomas 1946 Sialia sialis RussetNightingale Thrush X X X Skutch 1958 Catharus occidentalis Gray-cheekedThrush X X Van Tyne and Berger Catharus minimus 1976 European Blackbird Messmer and Messmer Turdus merula 1956 American Robin X Armstrong 1963 Turdusmigratorius Brown Towhee X X Marshall 1960 Pipilofuscus January 1983] Singingin FemaleGrosbeaks 107

TABLE 1. Continued.

Situations in which Suggested female sings• function(s)a Species NB NR I B FY TD PB-M C F-GM Source Abert's Towhee X X Marshall 1960 Pipilo aberti Orange-billedSparrow X Skutch1954 Arremon aurantiirostris Rose-breasted Grosbeak X X X X Ivor 1944, Dunham Pheucticus ludovicianus 1964 Northern Cardinal X X X X X Laskey 1944 Cardinalis cardinalis Common Grackle X Wiley 1976 Quiscalusquiscula Greenfinch X Ferguson-Lees1943 Carduelis chloris American Goldfinch X Berger 1953 Carduelis tristis Lawrence's Goldfinch X Linsdale 1950 Carduelis lawrencei Red Crossbill X Lawrence 1949 Loxia curvirostra White-winged Crossbill X Bent 1968 Loxialeucoptera Magpie Lark X X Robinson 1949 Grallina cyanoleuca Butcherbird X Robinson 1949 Cracticussp. Black-backedMagpie X Robinson 1949 Gymnorhinatibicen • NB - nest-building; NR = nest-relief; I - incubation; B - brooding; FY - feeding young; TD - territorial defense; PB-M - pair-bond maintenance;C - courtship;F-GM - family-groupmaintenance.

cording. During this period the situations in singing. Such singing apparently serves a ter- which females sang were noted, and hypoth- ritorial functionand, in addition, probably en- eses concerningthe function(s) of this song ables the female to maintain contact with the were derived. During the secondyear of the male. Females infrequently sang while forag- study, these hypotheses were tested experi- ing near the male (Weston 1947, pers. obs.). mentally. Singing, alone, is not sufficient to maintain a territory, at least early in the breeding sea-

SYNOPSIS OF THE BLACK-HEADED son, and agonistic encountersinvolving chas- GROSBEAK BREEDING CYCLE ing and even physical contact occurred. Nearly all chasesinvolved males, although several fe- The first birds arrived in the study area (Mal- male-female chases were observed, and, on ibu-Guinavah Campground, in Cache Nation- three occasions, females were observed chas- al Forest 10 km east of Logan, Cache County, ing males. On one of these occasions,a female Utah) about the first week in May. Observa- was observedchasing a male, and, upon land- tions indicated that some birds were paired ing, she sang one loud song. On another oc- upon arrival. Such pairs may have been formed casion a female appeared to engagein a brief on the wintering grounds or during migration. singing duel with a neighboring male. During the early part of the breeding season, Following territory establishment, Black- paired birds foraged together within their ter- headed Grosbeaksbecome progressivelyless ritories. The female usually followed the male aggressive.This change in behavior was quan- as he moved through the territory feeding and tified in two ways: (1) male singing rates de- 108 GARY Rr?cmso2½ [Auk, Vol. 100

:] TIME (•) TIME(•)

TIME(•) TIME(•)

Fig. 1. Representativesonograms of the songsof male (above)and female(below) Black-headed Gros- beaks.

clined as the seasonprogressed, and (2) the Incubation.--Both sexesare surprisingly vo- frequencyof intraspecificagonistic encounters cal on and around the nest. Males frequently (i.e. chasesand/or actualphysical encounters) sangwhile incubating.At timesthis songap- decreased(Fig. 2). peared to be in responseto the singing of Nest building.--Thefemale normallybuilds neighboringmales, i.e. a male would be qui- the nest, and I observed three instances in etly incubatingwhen, upon hearinga neigh- which females sang while involved in such boring male singing,the incubatingbird be- construction.Twice, females sang while gath- gan to sing. At other timesthe male'ssinging ering nestmaterials, and, on anotheroccasion, appearedto be a signal to the female that he a female was observedsinging while sitting in was about to leave the nest. a partially constructednest. On eachof these Femalesrarely sing while incubating.On two occasions a male was within a few meters of occasionsincubating females sang in apparent the singing female. responseto the singingof neighboringmales. January1983] Singingin FemaleGrosbeaks 109

30'

14 -12 -10 8 6 4 -2 0 2 4 6 TIME IN DAYS Fig. 2. Distribution of intraspecificagonistic encounters (chases and/or actual physical encounters) among male and femaleBlack-headed Crosbeaks (Day 0 = first egg ]aid).

In most cases, however, females showed no re- hatching, the adults maintained the same sponseto the singingof neighboringmales. scheduleas when incubating. Both adults fed On many occasionsa male or female would and brooded the young, and their behavior approachthe nest and find its mate quietly in- when changingplaces on the nest was similar cubating. At these times, males and females to that during incubation,with one significant frequentlyuttered "chip" callsor sang.The in- difference.As the broodingperiod progressed, cubating bird, upon hearing its mate, would the femalesbegan to sing more frequently (Fig. then leave the nest. 3). Parentalcare.--During the first few dayspost- By the eighth day post-hatchingthe young

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Fig. 3. Singing ratesof seIectedfemales during the 1977and 1978breeding seasons. 110 GARY RITCHISON [Auk, Vol. 100 were brooded infrequently. Adults approach- that both male and female Black-headed Gros- ing the nest to feed the young frequently vo- beakssing in the following situations:(1) as calized. These vocalizations were either "chip" they foragewith their matesbefore nesting, (2) callsor songs.Upon the arrival of the adult at after chasingneighboring males from their ter- the nest, the young grosbeaksimmediately be- ritory, (3) during nest building, (4) during in- gan calling. At times the young began calling cubation, (5) during change-oversat the nest upon hearing the calls or songsof their par- (both during incubation and brooding), (6) ents. when comingto the nest to feed the young, (7) The young may leave the nest as early as the when attempting to locate and feed fledged ninth day post-hatching,although departure at young. 10-14 days post-hatching was more common Theseobservations, along with thoseof Head (n = 21, •v= 11.5). After leaving the nest they (1902, 1904) and Weston (1947), suggestedthe scatteramong the shrubsnear the nest, perch- followinggeneralized functions of femalesong ing on low branches.During the first few days, in the Black-headed Grosbeak: (1) maintenance the young are rather quiet. As they are unable of thepair bond, (2)territorial defense, (3) fam- to fly at this time, they remain within a re- ily-group maintenance. strictedarea, and the adults generallyhave lit- Other reports (Ritchison in prep.) have re- tle trouble locating and feeding them (Weston vealed that female song in the Black-headed 1947, pers. obs.). If, however, a parent is un- Grosbeak does appear to be important in the able to locatea young bird, the parent will be- maintenanceof the pair bond, althoughit plays gin to utter "chip" calls and/or songs. Upon no role in territorial defense.The main objec- hearing their parents' vocalizations, young tive of the present study was to examine the grosbeaksrespond by uttering "phee-oo" and/ possiblerole of singingby femaleBlack-head- or "hunger-distress" calls. In this manner the ed Grosbeaksin family-group maintenance. parents and young are able to maintain contact. Maintaining contactbetween the parentsand MATERIALS AND METHODS their young obviouslybecomes more difficult Fieldworkwas conductedduring the breedingsea- after the young attain flight (approximately15 son of 1978at Malibu-Guinavah Campground.Eight days post-hatching). To maintain contact, younggrosbeaks from five differentnests were tested grosbeaksappear to use the same system de- in theseexperiments. All birds testedwere between scribed above. When parentshave food for the 10 and 17 days of age. young, but are unsure of the locationof the Apparatus.--Testing was conducted in an auto- mobile from which the birds had no contact (visual young, the parentsbegin to utter "chip" calls or vocal)with their parentsor other grosbeaks.The or, more frequently, songs. Upon hearing a test apparatusconsisted of a testing arenaand a port- parent, young grosbeaksutter "phee-oo" and/ abletape recorder(Nagra IIIB) connectedby cableto or "hunger-distress"calls. The parentthen flies a portable loudspeaker. to the young bird and feeds it. Occasionally, The arena was a box with floor dimensions of after hearinga parent sing, a young grosbeak 125 x 28.8 cm and walls 28.8 cm high. The floor and will fly to within a few meters or less of the long walls of the box were madeof wood while the adult and, if not fed immediately, will begin short walls consisted of cheesecloth.To provide a calling. referencegrid for the purposeof scoringa bird's po- At this stage(2-3 weekspost-hatching), fam- sition in the arena, the floor was marked out into 25 5-cm cells. In addition, the top of the apparatuswas ily groupsbegin to wander and no longerstay covered with a wire screen. within their territories. Because of this wan- During teststhe observersat in the front seatof dering, it is difficult to observespecific family the automobileand viewed the floor of the arena by groups over long periods, and, therefore, the means of a mirror suspendedat an angle above it. duration of such groups remains a question. For the playbackof recordedsongs the portableloud- Weston (1947) reported seeing young gros- speakerwas placedagainst the cheeseclothat one end or the other of the arena, and the tape recorder beaksbeing fed by adultsin earlyAugust, but was controlledby the observerfrom the front seat. he was unable to determine the actual length Playbackrecordings.--The songs of parents and of the dependent period. strangerswere recordedusing a Nagra IIIB tape re- Summarizingthe aboveobservations, I found corder with an Altec 633A microphone, which was January1983] Singingin FemaleGrosbeaks 111 housed in a 62-cm parabolicreflector. All recordings direct line from it to the end. In each 15-s interval were madeat a tape speedof 19 cm/s(71/2 ips). From the bird was thus scored as oriented toward the these recordingswere made 3-min test tapes, with speaker end, or as oriented toward the other end, or songsspaced at 15-s intervals. as unoriented. By counting up the intervalsin which Testing procedure.--Each bird was tested alone. orientation was one way and the intervals in which Initially, the young bird was placed at the central it was the other way I obtained the two scores.In a position on the floor grid of the arena, and its be- 3-min pre-test, test, or post-test, therefore, the max- haviorduring the next3 min wasobserved and scored imum possible score for one end, and for the two without playbackof any soundthrough the speaker. ends taken together, was 12. Such a period will be referredto as a "pre-test." At (ii) Position. As in the procedurefor orientation, the end of a pre-test, the young grosbeakwas re- two scoreswere obtained: one for the speaker end placed at the central position of the floor grid. For of the arena and one for the other end. The central the next 3 min songswere played, and again the position in the arena, from which a bird started out behavior of the bird was observed and scored. Such in eachpre-test, test, and post-test,carried a position a period with playbackwill be referredto as a "test." value of 0. The 5-cm transverse divisions of the floor Immediately after the test period, the young bird was carried position values, which increased from 1 to againreplaced at the centralposition of the floor grid. 12, reading from the central position to one side or Its behaviorduring the next 3 min was again ob- the other. At the end of each 15-s interval, a bird's served and scored.Such a period without playback positionon the floorgrid, determinedby the location after the test period will be referred to as a "post- of its feet, was notedand scored.Summing the scores test." for the two sides separatelygave the two position Eachbird was exposedto four typesof test in this scores.The maximumpossible score in a 3-min pre- way: two parental tests, in which the songsof its test, test, or post-test, for one side or for the two mother and father were played, and two "stranger" sidestaken together, was therefore144 (12 x 12). The tests, in which the songs of strange males and fe- maximum score would result if a bird spent all 12 maleswere played. The young birds experiencedeach intervals of a pre-test, test, or post-testwithin 5-cm of the four types of pre-test/test/post-testsequences of one or other of the end-walls of the arena. twice, once with the speaker at one end of the arena (iii) Position Change. A 15-s interval was scored and once with the speaker at the other end. The se- as positive for position changeif the bird's position quenceof presentationwas either parental-stranger- on the floor grid at the end of that interval was dif- parental-stranger or stranger-parental-stranger-pa- ferent from what it had been at the end of the pre- rental; as many birds experiencedthe one as the oth- ceding interval, regardlessof direction. The maxi- er. The sequencein which the endsof the arena were mum scorefor position changein a 3-min pre-test, used was also varied among birds, and the order of test, or post-test was therefore 12. ends was independentof the orderof test types. The (iv) Calling. The types and numbersof callsgiven complete sequenceof testing for a young grosbeak by a bird during the pre-test,test, and post-testpe- thus consistedof 8 pre-test/test/post-testruns, each riods were noted. 9 min in duration. I allowed 5 min between each run Playbackexperiments with free-living young.--In ad- for rewinding and changing test tapes on the tape dition to tests in the apparatus,a seriesof experi- recorder.The young bird remained in the arena dur- ments were performed with young grosbeaksin a ing this time. natural setting, i.e. while the birds were perched in For the tests the volume controlsof the tape re- a bush or small tree. Each experimentconsisted of corderwere adjustedso that modulometerreadings three 5-min segments(pre-test, test, post-test),and were similar for each tape used. No precise mea- throughout each test all sounds and nonvocal behav- surementsof soundintensity levelsin the arena were ior were noted. Each bird was tested twice with its made, however. mother'ssongs, and trials were at least 1 day apart. Scoring.--Forthe purposesof scoringthe behavior The speakerwas placed5-10 m from the young gros- of the young grosbeaks,each pre-test, test, and post- beaks in these experiments. test was divided into 12 15-s intervals. At the end of Playbackexperiments with adult females.--The re- each 15-s interval, a bird's position, orientation, and sponsesof femalesto playbackof the "phee-oo" calls the types and numbers of calls were noted. Details of their young were also examined in the field. The of the conventionsused for scoringthe behavior of proceduresfollowed in these tests were the same as the young grosbeaksare as follows: those used in the playback experimentswith the (i) Orientation. Two scores for orientation were young. Each experiment consisted of three 5-min accumulated:one for orientationtoward the speaker segments(pre-test, test, and post-test).Throughout end of the arena and one for orientation toward the each test all sounds and non-vocal behavior were other end. A bird was judged as orientedto one end noted. Eachfemale was tested twice with the "phee- or the other if it was pointed directly toward that oo" calls of one of her young. Different trials were end or in a direction within 20 ø to either side of the at least 1 day apart. 112 GARYRITCHISON [Auk, Vol. 100

TABLE2. Responsesof young grosbeaksto playbackof female songin the test apparatus.

Significancelevels t',c

PPT SPT PPT PT PAT Mean scores a'e VS. VS. VS. VS. VS. PPT SPT PT ST PAT SAT SPT ST PT ST SAT

Orientation to speaker 2.4 1.7 5.4 2.4 5.1 2.5 NS NS NS 0.05 NS Orientation to other end 1.3 1.9 1.3 2.0 1.2 2.8 NS NS NS NS NS Position score, speakerend 18.1 8.6 33.6 17.9 13.5 17.0 NS NS NS NS NS Position score, other end 31.0 37.1 28.8 32.4 32.0 25.0 NS NS NS NS NS Position change 2.2 4.5 2.4 2.0 0.6 1.2 NS NS 0.02 0.02 NS Number of "phee-oo" calls 17.4 15.7 54.2 27.0 37.6 26.8 NS 0.05 0.01 0.01 0.05 Number of "hunger- distress" calls 0.3 0.3 10.5 2.2 0 0 NS NS 0.01 0.02 NS

• The mean scoreswere derivedfrom two setsof experimentson eachof eight birds. The significancelevels are accordingto Wilcoxon matched-pairstests, two-tailed. • P < numbergiven: NS = not significant. •' PPT = parentalpre-test; SPT = strangerpre-test; PT = parentaltest; ST = strangertest; PAT = parentalpost-test; SAT = strangerpost-test.

RESULTS of response (Tables 2, 3). As in the parental tests,the young grosbeaks'first responseto the Responsesof younggrosbeaks to parentalsong songsof strangerswas often a seriesof "hun- in the test apparatus.--Theresults are summa- ger-distress"calls followed by nearly contin- rized in Tables2 and 3, togetherwith signifi- uous "phee-oo" calls. This vocal response to cance levels, given by Wilcoxon comparisons, the songs of strangers, however, was signifi- for the differencesamong all pre-tests, tests, cantly less pronouncedthan the responseto and post-tests.As these figures and compari- parental song (Tables 2, 3). In addition, sonsclearly show, the young grosbeaksmoved strangers'songs elicited no significant loco- about more, called more, and were more often motory responses.Finally, young grosbeaks oriented toward the speaker in responseto pa- showeda significantorientation away from the rental songthan to the songsof strangers.The speakerin responseto the playbackof the songs effectson a young grosbeak'sbehavior of play- of strangemales (Table 3). ing the parentalsongs were spectacularin most Playbackexperiments with free-livingyoung.- cases.Typically a bird's behavior in the pre- In the test apparatus, as well as under natural tests consistedof standing or sitting near the conditions, young grosbeaksresponded to pa- centerof the arenaand giving occasional"phee- rental songby uttering "phee-oo" callsand/or oo" calls. At the sound of the parental song, "hunger-distress"calls. A comparisonof the however, there was usually an immediate and responsesof young birds in the apparatusand sudden change:the young grosbeakraised its in a natural setting, however, revealeddiffer- head and started calling (often beginning by ences with respect to orientation and ap- uttering a seriesof "hunger-distress"calls fol- proach. Under natural conditionsyoung gros- lowed by nearly continuous"phee-oo" calls). beaks showed a significant tendency to In general, then, there was incessantcalling approachthe speaker(Table 4); birds in the test and locomotion (i.e. position change) in the apparatus,however, showed no suchtendency parental tests. (Tables2 and 3). Young grosbeaksin the ap- Responsesof younggrosbeaks to the songsof paratus did, however, show increased loco- strangersin the test apparatus.--Althoughthe motion. These results, although not predicted responsesof the young grosbeaksto playback initially, might be explainedas follows.In pre- of the songsof strangerswere lesspronounced, cocial species,such as the Laughing Gull (Lar- they were still significantin severalcategories us atricilla; Beer 1970a,b) and Ring-billed Gull January1983] Singingin FemaleGrosbeaks 113

TABrE3. Responsesof young grosbeaksto playback of male song in the test apparatus.

Significancelevels a'b

PPT SPT PPT PT PAT Mean scores a'b VS. VS. VS. VS. VS. PPT SPT PT ST PAT SAT SPT ST PT ST SAT

Orientation to speaker 2.8 2.4 3.2 1.5 2.3 2.4 NS NS NS 0.05 NS Orientation to other end 1.5 1.8 2.1 3.4 2.5 2.4 NS 0.02 NS NS NS Position score, speaker end 13.1 11.8 18.2 11.5 27.2 31.9 NS NS NS NS NS Position score, other end 12.3 23.6 37.0 36.4 19.8 36.6 NS NS NS NS NS Position change 0.6 0.7 5.2 1.7 1.7 1.1 NS NS 0.01 0.01 NS Number of "phee-oo" calls 17.9 23.0 62.9 44.1 37.4 28.7 NS 0.01 0.01 0.01 0.01 Number of "hunger- distress" calls 0 0.1 7.9 9.3 2.7 0 NS 0.02 0.02 NS NS

Mean scoresand significancelevels as in Table2. PPT = parentalpre-test; SPT = strangerpre-test; PT = parentaltest; ST = strangertest; PAT = parentalpost-test; SAT = strangerpost-test.

(L. delawarensis;Evans 1970b), chicks have been less and call or attempt to "fly" out of the ap- found to show orientation and approach re- paratus to locate and approach their unseen sponsesto the played-backcalls of their par- parent. Such reasoning might explain the ab- ents. Because precocial chicks normally ap- senceof significantorientation or approachbe- proach their parents by walking or running, havior by young grosbeaksin the test appa- the quickestroute to a "callingparent" (i.e. the ratus. speaker) is to orient toward and approach the Playbackexperiments with adultfemales.--The sound source. In the grosbeak,on the other responsesof females to the playback of the hand, young birds come in contactwith their begging calls ("phee-oo" calls)of their young parents by flying toward them or, if they are were significantin severalcategories, i.e. dis- not yet capableof flight, by remainingmotion- tanceof closestapproach, number of songs,and less and calling the adults toward them. In the syllablesper song (Table 5). Becauseonly the apparatus,therefore, young grosbeakswould calls of their own young were played to indi- not be expectedto walk or run toward the sound vidual females, these results do not constitute source(speaker), but instead(depending on the proof of individual vocal recognitionof young age of the young) would either remain motion- by females. As will be discussedlater, how-

TABLE4. Responsesof free-living young Black-headedGrosbeaks to playback of their mother's song.

Closest Number Number approach Number of of "hunger- Number (m) of flights "phee-oos" distress" of "chips" Responsesa Pre-test period (PTP) 7.00 0 0.20 0 0.10 Test period (P) 3.30 0.80 2.50 1.60 0.40 Post-testperiod (PP) 3.50 0.30 0 0 0.30 Significancelevels • PTP vs. P 0.05 0.05 0.05 NS 0.05 PTP vs. PP 0.05 NS NS NS 0.05 P vs. PP NS 0.05 0.05 NS NS

Values for responsesare averagesfor all tests.The significancelevels are accordingto paired t-tests (n = 6). p < numbergiven; NS = not significant. 114 GARY RITCHISON [Auk, Vol. 100

TABLE5. Responsesof femalesto playbackof the "phee-oo"calls of their young.

Closest approach Number Syllables Number Number Number of Number (m) of songs per song of "chips"of "wheets""distress"of flights Responsesa Pre-test period (PTP) 7.00 0 0 5.70 0 0 5.70 Test period (P) 3.00 1.70 5.60 23.20 10.40 0.20 7.20 Post-testperiod (PP) 4.80 3.80 4.70 13.90 1.20 0 3.20 Significancelevels b PTP vs. P 0.01 NS NS 0.05 NS NS NS PTP vs. PP 0.05 0.05 0.001 NS NS NS NS P vs. PP 0.05 0.05 0.05 NS NS NS 0.01

Valuesfor responseare averagesfor all tests.The significancelevels are accordingto pairedt-tests (n = 4). P <: numbergiven; NS = not significant.

ever, these results do lend support to the con- stated that a young Mockingbird (Mimuspoly- clusionthat singingby femalesis importantin glottos)recognized the voiceof the parentwho family-group maintenance. fed it and startedto beg on hearing it. Nestling European Blackbirds (Turdus rnerula) are re-

DISCUSSION ported to know their mother by her food call (Messmer and Messmer 1956), and fledged Recent studies involving the recognitionof young apparently recognize their fathers' parents by their young have concentratedon vocalizations(Thielcke-Poltz and Thielcke 1960). colonial species, e.g. Common Murres (Uria Young Ring Doves (Streptopeliarisoria) and aalge; Tschanz 1965, 1968), Black-billed Gulls Chiffchaffs (Phylloscopuscollybita) are also re- (Larus bulleri; Evans 1970a), Laughing Gulls ported to recognize the calls of their mother (Beer1970a, b), Ring-billed Gulls (Evans1970b), (Craig 1908,Gwinner 1961).Other authorshave and Black-LeggedKittiwakes (Rissatridactyla; reported observationssuggesting that altricial Cullen 1957). Evidenceof individual recogni- young may recognize parental song. For ex- tion betweenparents and young has been found ample, Saunders(1929) referred to young House in every colonial speciesin which it has been Wrens (Troglodytesaedon) being stimulatedto sought, with the exceptionof the Blackqegged opentheir bills by the males'song. Young Snow Kittiwake. The survival value of this recogni- Buntings(Plectrophenax nivalis) may alsobe able tion in colonial speciesseems quite apparent. to distinguishtheir father'ssong from the song Becausea young bird is surroundedby adults of other males (Armstrong1963). The present who are not its parents, who are unlikely to studyprovides clear evidence that young Black- feed it, and who may even attack it, individ- headed Grosbeaksare able to recognize the uals who beg only from their own parents songsof their parents. should conserveenergy and have a selective Grosbeakfamily groupsbegin to wander 2- advantage over indiscriminating young. The 3 weeksafter hatchingand no longerstay with- caseof the Black-leggedKittiwake may be re- in their breeding territories. Becausethe birds garded as an exception that proves this rule, are moving through thick vegetationin unfa- for in that speciesthe young remain confined miliar areas,maintaining contact becomes more to the nest until they fledge (Cullen 1957), so difficult. Under such conditions individual vo- that up to that time the youngdo not normally cal recognitionis essential.Without such rec- encounter adults other than their parents. ognition, the maintenance of family groups In contrast to the situation described for co- would probably be impossible.The need for lonial species,there is little information avail- the recognition of parental song by young able concerningthe recognitionof parents by grosbeaks,therefore, is apparent. Even with their young in noncolonial, altricial species. such recognition,however, it would certainly Only a few observationssuggesting the pos- be .possiblefor young grosbeaksto stray from sibility of suchrecognition have been report- the family 'groups. Given that possibility, a ed. For example, Michener and Michener (1935) positive responseto the songs of other adult January1983] Singingin FemaleGrosbeaks 115 grosbeakswould be advantageous.Such a re- BAKUS,G.J. 1959a. Observationsof the life history sponse to strange adults would presumably of the Dipper. Auk 76: 190-207. tend to enhancethe chancesof "adoption" by 1959b. Territoriality, movementsand pop- ulation density of the Dipper in Montana. Con- foster parents. This, in fact, appears to be the dor 61: 410-425. "strategy" used by young grosbeaks.Although BALDWIN, F. M., H. S. GOLDIN, & M. METFESSEL. fledglings respond more strongly to the songs 1940. Effects of testosterone on female Roller of their own parents,they alsoshow significant Canaries under complete song isolation. Proc. responsesto the songs of strange males and Soc. Exp. Biol. Med. 44: 373-375. females (Tables 2, 3). BAPTISTA,L. F. 1978. Territorial,courtship and duet The responsesof young grosbeaksto paren- songsof the Cuban Grassquit(Tiaris canora). J. tal song representbut one side of the parent- Ornithol. 119: 91-101. young relationship. The responsesof parents BEER,C. G. 1970a. On the responsesof Laughing to the vocalizations (or absence of vocaliza- Gull chicks to the calls of adults. I. Recognition of the voices of the parents. Anim. Behav. 18: tions) of their young are equally important. 652-660. Among older fledglings, contactwith parents 1970b. Individual recognition of voice in generallyresults from thesefledglings flying to the socialbehavior of birds. Adv. Study Behav. the parents in response to parental song. 3: 27-74. Youngerfledglings, however, as well as young BENT,A. C. 1968. Life histories of North American birds that have left the nest but are not yet Cardinals,grosbeaks, buntings, towhees, finch- capableof flight, maintain contactwith parents es, sparrows,and allies. U.S. Natl. Mus. Bull. by means of the mutual recognition system No. 237. discussedpreviously, i.e. an adult with a food BERGER,A. J. 1953. Female American Goldfinch item, but unaware of the location of its young, warbles while incubating. Wilson Bull. 65: 217- 218. will often begin singing to elicit begging BERTRAM,B. 1970. The vocalbehavior of the Indian ("phee-oo" and/or"hunger-distress" calls) from Hill Mynah. Anim. Behav. Monogr. 3: 81-192. its young. In this way a parent is able to locate BLANCHARD,B. D. 1941. The White-crowned Spar- its young. The responsesof females to the rows (Zonotrichialeucophrys) of the Pacificsea- playback of the "phee-oo" callsof their young board: environment and annual cycle. Univ. appearto verify the existenceof sucha system. Calif. Publ. Zool. 46: 1-178. Upon hearing the playback,females showed a CONANT,S. 1977. The breedingbiology of the Oahu significant approach response,as well as sig- Elepaio. Wilson Bull. 89: 193-210. nificant increasesin the number of flights and CRAIC,W. 1908. The voicesof pigeonsregarded as number of "chip" calls (Table 5). Such re- a means of social control. Amer. J. Sociol. 14: 66-100. sponses would, under natural conditions, en- CULLEN,E. 1957. Adaptations in the Kittiwake to able a parent to locatea young grosbeakquick- cliff-nesting. Ibis 99: 275-302. ly. On the other hand, once playback ended, DUNHAM, D. W. 1964. Behavior of the Rose-breast- females showed significant increasesin sing- ed Grosbeak, Pheucticus ludovicianus. Unpubl. ing rates. Under natural conditions this would Ph.D. Thesis. Ithaca, New York, Cornell Univ. elicit calling by young grosbeaksand, thus, al- EVANS,R. M. 1970a. 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