J. Field Ornithol., 61(2):245-248

RENESTING BY A COMMON

MICHAEL C. ZIcus MinnesotaDepartment of Natural Resources WetlandWildlife Populations and ResearchGroup I02 23rd Street Bemidji, Minnesota5660• USA Abstract.--Althoughrenesting occurs in mostNorth Americanwaterfowl tribes,reports for the are mostlyspeculative and renestingby CommonGoldeneyes (Bucephala clan- gula) has not been confirmedpreviously. A female goldeneyethat abandoneda clutch of seveneggs while laying began laying a secondclutch within a maximum of 19 d and successfullyhatched it. Renestingis probablyinfrequent in CommonGoldeneyes. Successful renestingrequires a minimum of 6-7 additionalweeks from renestinitiation to hatch,but the nestingseason is comparativelyshort acrossthe breedingrange. Lowered survivalof late hatchedyoung combinedwith a relatively low risk of nest predationmay offer little advantageto renesting.

REANIDAMIENTO POR PARTE DE BUCEPHALA CLANGULA Sinopsis.--Aunqueel reanidamientoocurre en la mayoriade las tribusde patosnorteameri- canos,informes en los Mergini sonmayormente especulativos. E1 ranidamientoen Bucephala clangulano ha sidopreviamente confirmado. Una hembrade estaespecie que abandono7 huevossin haber terminadola camada,comenz6 una nueva 19 dias mils tarde y la empol16 exitosamente.E1 reanidamientoen B. clangulaprobablemente ocurre con poca frecuencia. Un reanidamientoexitoso requiere un minimo de 6-7 semanasadicionales desde el comienzo de estehasta el comienzodel eclosionamiento.Pero la gpocade anidamientoes compara- tivamentecorta a travgsdel fireageogrfifica en dondeanida esta especie. La baja supervivencia de las camadasque eclosionantarde durante la gpocade reproducci6n,combinado a un riesgobajo de depredacionpodrla proveer, si acaso,alguna pequefia ventaja al reanidamiento. Renestinghas beenreported for all North Americanwaterfowl tribes. Most dabblingducks and diving ducksare persistentrenesters (Alliston 1979,Doty et al. 1984, SowIs1955, andothers). Renesting is alsocommon in the Wood Duck (Aix sponsa)and the whistling ducks (Delnicki and Bolen 1976, Grice and Rogers 1965). In wet years, significantportions of the annual productionof youngin early-nestingspecies sometimes are producedthrough renesting (SowIs 1955:141). Some geese and the Ruddy Duck (Oxyurajamaicensis) also renest (Atwater 1959, Tome 1987) al- thoughperhaps less frequently than membersof othertribes. In contrast, exceptfor CommonEiders (Somateriamollissima), reports of renestingin the relatively large Mergini tribe are mostly speculative(Cooch 1965; cf., Palmer 1976; Sarbello 1973). Renestingby a Common Goldeneye (Bucephalaclangula) has not been confirmedpreviously. This note documentsrenesting by a Common Goldeneyefemale in northcentralMinnesota. I observedthe eventon a 16 ha pond with a 30 ha adjoiningsedge meadow and floating sedgemat. Water depthswere lessthan 1.5 m, and hardstembulrush (Scirpusacutus), waterlily (Nym- phea tuberosa),and various pondweeds(Potamogeton spp.) occurred throughout.Cattail (Typha latifolia) standswere also found along parts of the wetland shoreline. Public use was limited to moderate levels of

245 246] M.C. Zicus J.Field Ornithol. Spring 1990 bait-leechtrapping by 4-6 individualsin April to June. Sixteenwaterfowl nest boxes were attached to trees around the wetland. The femalewas bandedinitially with a U.S. and Wildlife Service leg band while laying in a nest box on 4 May 1983. On 11 May, she was fit with a plasticnasal saddle(Doty and Greenwood1974) as part of a time budgetstudy. She hatchedher 11 egg clutchon 3 Jun. The female returned to the same nest box in 1984 and successfullyhatched an eight egg clutchon 1 Jun. She returned again in 1985; one eggwas found in the samenest box on 4 Apr. The nest containedseven eggs on 17 Apr when the female was capturedto replacethe nasal saddlethat she had lost. Within a few days, it was obviousthat the nest had been abandoned.During the next 2 wk, the female accompaniedby a drake was seenperiodically on the wetland,usually in their previouslyoccupied territory. On 13 May, I observedthe female leavea nestbox 30 m from the one that shehad usedin the past. Eggswere first notedin this nest on 9 May when it containedtwo. Subsequentobservations confirmed that the femalewas nestingin the box, and shehatched a seven-eggclutch on 16 Jun. The exact length of the relaying interval could not be determined becauseof egg laying by femalesfrom 4-7 other goldeneyepairs using the wetland. Four of thesepairs foragedregularly on easily delineated territoriesthat were defendedvigorously. Females in three of theseres- ident pairs alsowere markedwith nasalsaddles. Occasionally, 2-3 non- residentunmarked pairs usedthe wetland as well. Common Goldeneye femalesgenerally lay an eggevery other day and have a typical clutchof 7-9 eggswhen intraspecificegg laying is uncommon(Palmer 1976:394, Zicus unpubl. data). In addition to the renestingfemale's nest, nests incubatedby two other nasal-saddledresident females were locatedin nestboxes. Both of thesecontained eight eggs. Although none of the active 1985 goldeneyenests had a clutchsize that indicatedeggs had beenlaid in it intraspecifically,a total of five additionalgoldeneye eggs (dump eggs) also was found in four other nest boxes. Infrequent nest inspections resultingin uncertainlaying datesindicated any of the femalesusing the wetland could have laid the dump eggs.Considering goldeneye laying rates,the maximumlength of time elapsingbetween abandonment of the first nest and initiation of the renest was 19 d. However, continuation nestshave beennoted for a number of waterfowl species(Cooper 1978: 77, Palmer 1976:65, Sowls1955:136). Selectionof nest-boxnesting sites in all four known nestingattempts by the renestingfemale suggested she probablydid not lay additionaleggs in any nearby natural cavities.If any of the known dump eggswere laid as a resultof the renestingfemale continuingher initial clutch, the renestinginterval would have been somewhat less than 19 d. Because the abandoned nest contained seven eggs,it is unlikely that the renestinginterval would have beenshortened by more than 3-5 d even if continuationlaying had occurred. How commonis renestingin goldeneyes?Lack of previousdocumen- tation and a number of specifictraits suggestrenesting is infrequent. Vol.61, No. 2 CommonGoldeneye Renesting [247

Clutch sizesof 7-9 eggscombined with a low egg laying rate result in laying periodsof 2-3 wk. With incubationtaking approximately30 d (Bellrose 1976:435; Zicus, unpubl. data), from 6-7 wk are thus re- quiredto lay and hatcha typicalclutch. Goldeneyes are alsoearly nesters and may rely on nutrientsacquired prior to arrival in nestingareas for clutchproduction, as do other early nestingwaterfowl (Drobney 1980, Korschgen1977). Nestingseasons are comparativelyshort across golden- eye'sbreeding range, and successfulfledging of youngfrom a renestmight be a problemfor all but the earliestnesting females given the time needed to acquirenutrients and to lay and incubatea secondclutch. Dow and Fredga(1984) observeda lower survivalto threemonths for youngCom- mon Goldeneyeshatched later in the nestingseason. Lastly, predation rates on nestsin tree cavitiesare generallybelieved to be lower than for nestsfrom groundor overwatersites. Natural selectionfavoring renesting due to predationin nestinghabitats occupied by goldeneyesmay be quite lOW.

ACKNOWLEDGMENTS

I thank S. K. Hennesfor assistancein the field and A. L. Drewes for help preparingthe manuscript.L. N. Hamilton typedthe neededdrafts. R. E. Lake, R. T. Eberhardt,J. O. Evrard, and B. Baconhelpfully reviewedearlier versionsof the manuscript.

LITERATURE CITED

ALLISTON,W.G. 1979. Renestingby the Redhead Duck. Wildfowl 30:40-44. ATWATER,M. G. 1959. A study of renestingin Geesein Montana. J. Wildl. Manage. 23:91-97. BF.•.•.e,os•., F. C. 1976. Ducks, geese,& swansof . Seconded. Stackpole Books,Harrisburg, Pennsylvania. COOCH,F.G. 1965. The breedingbiology and managementof the Northern Eider (So- materiamollissima borealis) in the CapeDorset Area, NorthwestTerritories. Can. Wildl. Serv., Wildl. Manage. Bull. 2. No. 10. Coo?•.R,J. A. 1978. The history and breedingbiology of the Canada Geeseof Marshy Point, Manitoba. Wildl. Mongr. 61. DF.LNICKI,D., ANDE.G. BOLF.N.1976. Renestingby the Black-belliedWhistling Duck. Auk 93:535-542. DOTY,H. A., ANDR. J. GRF.F.NWOOD.1974. Improvednasal-saddle marker for . J. Wildl. Manage. 38:938-989. •, D. L. TRAUGER,AND J. R. SERIF.. 1984. Renestingby Canvasbacksin south- westernManitoba. J. Wildl. Manage. 48:581-584. DOW, H., ANDS. F•tF.DG^. 1984. Factorsaffecting reproductive output of the goldeneye duckBucephala clangula. J. Anim. Ecol. 53:679-692. DROBNEY,R.D. 1980. Reproductivebioenergetics of Wood Ducks.Auk 97:480-490. GRICE,D., ANDJ.P. ROGERS.1965. The Wood Duck in Massachusetts.Final Rep. Fed. Aid Proj., Mass. Div. Fish and . KORSCHGEN,C.E. 1977. Breedingstress of femaleeiders in Maine. J. Wildl. Manage. 41:360-373. P^LMER, R. S., editor. 1976. Handbook of North American . Vol. 3. Yale Univ. Press, New Haven, Connecticut. SARBF.LLO,W. 1973. Renestingof the American Eider in PenobscotBay colonies.M.S. thesis, Univ. of Maine, Orono. 248] M.C. Zicus J.Field Ornithol. Spring 1990

Sowcs, L. K. 1955. Prairie ducks.Wildl. Mgmt. Institute. StackpoleCo., Harrisburg, Pennsylvania. TOME, M.W. 1987. An observationof renestingby a Ruddy Duck, Oxyurajamaicensis. Can. Field-Nat. 101:153-154. Received17 May 1989; accepted1 Dec. 1989.