Vol.52, No. • General,¾ote.• [239 winds,clear vsovercast skies, and 65 vs 31 recordedper hour in the Manometradar log. The lack of migrantsduring the morning hours on all daysindicates that the early morning eastwardmovements seen at Mahomet on the 25th and 27th did not crossCape Cod Bay. We thank B. Ackermanfor hisassistance in scoringthe radar filmsand A.D. Colburn, captain of the Asterias,for assistanceduring the observations.--TIMOTHYC. WILLIAMS ^Nr• JANETM. W•LL•^•S, SwarthmoreCollege, Swarthmore, PA 19081. Received 15 June 1980, accepted20 Feb. 1981.

Uptilted Bills in Thrushes.--In a previous study of head lifting coincidentwith vocalizingby certainpasserines (Clark 1976) I notedthat silentAmerican Robins (Turdus migratorius)often perch with the bill tilted slightly above the horizontal. Extending this finding during many additional hours afield in the United Statesand throughout a year in England,I have found that certainother thrushesalso commonly hold the bill above the horizontalwhile pausingsilently on the ground or on branches,in contrastto other birds that hold the bill horizontallyor downwardlytilted in similarsituations. On numerous occasionsI have seen uptilted bills, usually lessthan 30ø above the horizontal,for silentand nondisplayingindividuals during both terrestrialand arboreal pausesfor the European Blackbird (T. merula), (T. iliacus),Song (T. philomelos),Mistle Thrush (T. viscivorus),and AmericanRobin. When foragingon short grasssuch as lawns,these 5 speciescommonly make a seriesof movesover the ground punctuatedby pauses,often lessthan 3 s in duration,with the angleof uptilt highestin these pauses.Uptilted bills do not occur in every pause;the head can be held at varied angles,sometimes lowered or tilted to the side. Neverthelessone or more pauseswith an uptilted bill is ordinarilyseen for any of thesespecies within a minute of watchingfrom a suitabledistance and direction. In contrast,I have rarely or never detectedan uptilted bill for other avian speciesduring numerouspauses over many minutes(e.g., Mallard (Anasplatyrhynchos), Wood Pigeon( Columba palumbus), Mourning Dove (Zenaidamacroura), Tufted Titmouse (Parusbicolor), European Goldfinch (Cardueliscarduelis), House Finch ( Carpodacusmexicanus), Blue Jay ( Cyanocittacristata), and Magpie (Picapica)). Specieswith frequently uptilted bills in pausesdiffer so conspicuouslyfrom those lackingthis trait that even small samplesappear sufficientto reveal thosewith a frequent uptilt. For example, I have consistentlyseen uptilts for Veeries (Catharusfuscescens; 6 records),Hermit Thrushes(C. guttatus;6), and Wood Thrushes(Catharus mustelinus; 7). I also noted uptilted bills for single individualsof Varied Thrush (Zoothera[=Ixoreus] naevia),Gray-cheeked Thrush (Catharusminimus), Swainsoh's Thrush (C. ustulatus),and (Turduspilaris), but further observationsare desirableto verify that frequently uptilted bills are indeed characteristicfor the latter 4 species.Two other specieswith apparentlyfrequently uptilted bills during pausesare the partially terrestrial woodpeck- ers: the Common Flicker (Colaptesauratus; 12 records)and the European Green Wood- pecker(Picus viridis; 2), whichin my observationsexhibited uptilts during pausesboth on the ground and when perchedtransversely on limbs. The taxa mentioned thus far appear to have either frequently uptilted bills during pauses,or uptilts only rarely or not at all. However, the European Robin (Erithacusru- becula),which is also placed in the thrush subfamilyTurdinae but widely separatedfrom the speciesmentioned above, appears to be intermediatein frequencyof an uptiltedbill; I noted 12 pauseswith uptilts and 13 without, valuessignificantly different from the correspondingfigures of 36:3 for SongThrushes (X 2 testsboth corrected and uncorrected for smallsamples; P < .01). Thosethrushes with a frequentlyuptilted bill during pausesapparently do not elevate the bill further during songas I notedwithout exception for the Veery (6 records),Wood Thrush (6), Blackbird (32), SongThrush (26), and Mistle Thrush (9), all of which are thus like the American Robin and unlike certain American emberizines,parulids, and other Passerineswhich often raisethe head coincidentwith song(Clark 1976). Probablythe uptilted bill in the thrushesduring pausesresults simply from a slightly 240] GeneralNotes J.Field Ornithol. Summer 1981 raised head, but this is difficult to verify in the field. Severalobservers (Witherby et al. 1938, Goodwin 1978, Simms1978) have correctlynoted that the body inclinationof the EuropeanBlackbird on the ground is usuallyless upright than that of the Songor Mistle thrush or American Robin. Correspondingly,I have noted that the angle of the bill above the horizontalin Blackbirdsis often lessthan that of theseother Turdusspecies. Blackbirds dig with the bill in litter much more than do theseother Turdusspecies (Simms 1978, pers.obs.), and I suggestthat the differencein postureduring pausesmight be related to the differencein foraging.Much remainsto be learnedabout the frequencyof uptilted billsamong birds in generaland aboutthe functionaland possiblesystematic significance of the frequent uptilt in thrushes. I thank D. M. Broomand R. J. Craig for helpful discussionand Prof. K. Simkissfor generouslyproviding facilities in the Departmentof Zoology,University of Reading,En- gland.

LITERATURE CITED CL^RK,G. A., JR. 1976. Taxonomicdifferences in headmovements of vocalizingpasser- ines.-banding 47:123-128. GOODWIN, D. 1978. Birds of man's world. Cornell Univ. Press, Ithaca, New York. S•MMS, E. 1978. British thrushes. Collins, London. WITHERBY,H. F., F. C. R. JOURDAIN,N. F. TICEHURST,AND B. W. TUCKER. 1938. The handbookof British birds. Vol. 2. Witherby',London. GEORGEA. CLARK,JR., BiologicalSciences Group, University of Connecticut,Storrs, CT 06268. Received10 July 1980, accepted20 January 1981.

CanadaGoose Feeding DamagesShellfish Beds.--During the fall of 1976, the Mas- sachusettsShellfish Officers Association (MSOA) lodgeda complaintwith the Divisionof Fisheriesand Wildlife that CanadaGeese (Branta canadensis) were feeding on softshelled clams(Mya arenaria).A review of the literature revealedno reports of Canada Geese ingestingshellfish. A questionnaireprepared by Burke Limeburner, Presidentof MSOA wasdistributed in 1977at the MSOA convention.Officers from 11 townsindicated they had "majorproblems" with geeseon shellfishbeds, 4 indicated"minor problems,"and 8 had no problems.I contactedseveral of the officersreporting major problems.Officers differed in their viewsof when depredationson clam bedswere greatest.Some felt the problemoccurred during the summerwhen seedclams were smallenough to be ingested by geese,while othersfelt that winter wasthe worsttime when wintering populationsof geesewere greatestand other food sourceslimited. I selected3 townson Cape Cod for field observationsof Canada Geese.Seven - servationperiods of 3-4 h durationwere made betweenAugust and November1977. I observedno CanadaGeese feeding over clambeds although I did observeMallards (Arias platyrhynchos)and Black Ducks(,4. rubripeN)doing so. These birds engagedin puddling activities,treading the bottomduring shallow water periods, creating bowl shaped depres- sions.This actionstirred up the bottom,exposing previously-covered food items.Shellfish officersstated that they observedCanada Geese performing similar actions. No further field observationswere madeuntil January 1980when I observedCanada Geesefeeding over clam beds and performingthe puddlingactions described by Shellfish Officers.The geese,however, appeared to be feedingon grassesinundated by the high tide. ! alsotalked with WinthropTaylor, a deputyshellfish officer with formal trainingin biologyand an avid goosehunter. He reportedobserving geese puddling in shellfishareas and that wheneverhe shotone of thesebirds he found only sedge(Carex sp.) roots in the gizzard. A total of 188 gizzardswere collectedfrom geeseshot along coastalMassachusetts during the 1977-80 hunting seasons.The sampleincluded 86 from townswhere shellfish officersindicated geese were damagingclam beds.One gizzard contained3 small,un- identified salt water snails. None contained shellfish.