GROWTH AND ENERGETICS OF ARCTIC TERN CHICKS (STERNA PARADISAEA )
MARCEL KLAASSEN?2 CLAUS BECH,1 DIRKJAN MASMAN, 2'3AND GURI SLAGSVOLD • XDepartmentof Zoology,University of Trondheim,N-7055 Dragvoll,Norway, 2ZoologicalLaboratory, University of Groningen,P.O. Box14, 9750AA Haren,The Netherlands, and aCenterfor IsotopeResearch (C.I.O.), Universityof Groningen, Westersingel34, 9718 CM Groningen,The Netherlands
ABSTRACT.--Westudied energy requirementsof Arctic Tern chicks(Sterna paradisaea) in Ny ,idesund,Svalbard (79øN, 12øW) with special emphasis on thermoregulatory andactivity costs.We useddoubly labeled water to estimateenergy expenditurein the field (Ea•w)and madelaboratory measurements of thedifferent components of totalenergy requirement Comparisonof DLW-estimateswith oxygen consumptionmeasurements showed that underestimatedtotal energy expenditure4.5-16.0% depending on the duration of the ex- periment. This was probablydue to incorporationof isotopesin newly synthesizedtissue. Field estimatesof total energy expenditurefrom Ea•• were correctedaccordingly. A tern chick model was usedto measureoperative temperature (T,). At middayT, reachedvalues up to 20øCabove ambient temperature (Ta) which ranged from 3.4-9.0øC. Based on thefield estimates of Ea•wand Teand the laboratorymeasurements of basalmetabolic rate and thermalconduc- tance,we concludethat therewas a considerableenergy saving (456 kJ = 26%of •eq) during the first 10-11 daysof life, due to parentalbrooding. After this period,when the parents stopbrooding, the energyrequired for thermoregulationaccounted for only 16%of F_•q.From 10 days after hatching onwards,the energy needed for activity increasedconsiderably, up to 50%of Er,qjust before fledging (Day 20). Comparisonof the energybudgets of ArcticTern chickswith the more southerlyoccurring closely related Common Tern (S.hirundo; Ricklefs and White 1981)revealed only a slightly higher energyexpenditure in the ArcticTern chicks. Received5 April 1988,accepted 23 November1988.
ENERGYexpenditure of chicksliving in arctic ing, with specialemphasis on thermoregulatory and antarctic environments has been consid- costs.We measuredfield growth, operativetem- ered to be dominatedby the costsfor thermo- perature, and total energy expenditure using regulation.Many physiologistshave focused on doublylabeled water. In additionwe analyzed the ability of chicksto copewith low environ- carcassesand measuredoxygen consumption in mental temperatures(e.g. Maher 1964, Norton relation to ambient temperature in chicks of 1973, Aulie and Steen 1976, Boggset al. 1977, different ages.From this we estimatedthe costs Pedersen and Steen 1979, Bech et al. 1984, Jar- of basalmetabolism, growth, thermoregulation, gensen and Blix 1985, Taylor 1985, Boersma activity, and total energy requirements,which 1986). However, the abiotic environment of were comparedwith the Common Tern (S. hi- chicksat high latitudesand the contribution of rundo)and the Sooty Tern (S. fuscata;Ricklefs thermoregulatorycosts to their total energy ex- and White 1981). penditure have not been quantified precisely. In addition to estimatingthermoregulatory costs in relation to other energy requiring processes, METHODS interspecific comparison of closely related speciesfrom different latitudes should provide Westudied Arctic Tern chicks in Ny,•lesund, Sval- bard (79øN,12øW) from 12 July to 6 August 1986.The a better understanding of the influence of the breedingbiology of theArctic Terns in Ny ,•lesund polar environment on chick energy require- has been describedby Bengtson(1971) and Lemme- ments. tyinen (1972). We studied energy requirementsof Arctic The colonywas visited regularly and individually Tern (Sterna paradisaea)chicks in the Arctic marked chicksof known age were weighed with a throughout the period from hatching to fledg- Pesolaspring balance.Wing length was measured 240 The Auk 106:240-248. April 1989 April 1989] ChickGrowth and Energetics 241 with a ruler to the nearest ram, and tarsus and head Eth= h(T• - Te) - BMR kJ.g-•.day-• (3) length with a flexible ruler to 0.1 min. We determinedbody compositionin I1 chicksthat rangedin agefrom 0 to 20 days,and in 2 adult birds. if h(Tb- Te) > BMR, where Tb is body temperature If the ageof the chickswas not knownfrom hatching (39'C; Klaassenet al. 1989). If h(Tb - Te) _
5331321413795543454654431231 5 120- 2(•13622151063223 2 3 2142113 1214 • 90-
14
30-
0 54352716127105 4 2 5 2 6 4 5 6 3 3 31 1 3 1 111 1 2 32122 33 4 70-
60-
50- •20
40-
30- 1ø)30 • 1•) 16 20 ADULT age, days age, days
Fig. 1. Developmentof bodymass (A), tarsuslength (B), head length (C), andwing length(D) asa function of age in Arctic Tern chicks.Measurements on adults are included for comparison.The line in (A) was calculated(Eq. 4), whereasthe lines in (B) and (D) were fitted by eye.
RESULTS Cw = 84.6(t + 1)-ø-ø9'% (5)
The increaseof body masswith age (t, days) (r = -0.875, P < 0.001). The amounts of lipid (Fig. 1A) wasfitted to a logisticequation (Rick- and nonlipid dry mass(Fig. 2B) were accumu- lefs 1967): latedwith a nearly constantratio from the third day of age onwards.About 28% of the water- M = 115/(1 + 8.0e-ø'263t) g (4) free tissue was lipids. As a consequence,the increaseof energy density of body tissue(Ce,) The tarsushad a high growth rate from hatch- with age (Fig. 2C) was mainly due to the de- ing until Day 7 when it had nearly reached creasein water content.This increasein energy adult length (Fig. lB). Head length increased content was describedby: nearly linearly with age (Fig. 1C). In contrast, the wing only grew rapidlyafter Day 5 to Day C., = 3.65(t + 1)0.306 kJ/g wet (6) 8, and reached60% of adult length at fledging around Day 22 (Fig. 1D). (r = 0.929, P < 0.001). From the growth curve The carcassanalyses enabled us to convert (Eq. 4) and the relationshipfor energy density body massgain to energy depositionand to of body tissuewith age (Eq. 6), we calculated estimatetotal body water content,necessary for the daily costfor tissuedeposition (E,i,). Assum- the calculationsof CO2production from the iso- ing a synthesisefficiency of 75%(Ricklefs 1974), tope enrichmentsin the blood samples.Body the costsfor biosynthesis(Esyn) were derivedby water content(Cw) decreased with age (Fig. 2A) E,yn = E,,0.33kJ/day. followingthe expectedpattern (Ricklefs 1974) We estimatedthe costsfor thermoregulation and was describedby the equation: in the field by using the information of the April 1989] ChickGrowth and Energetics 243
ied considerably.On cloudydays with low solar 80- radiationthe operativetemperature was slight- ly elevatedabove the ambienttemperature; but on cleardays, operative temperature could reach $70- values of up to 29øC(Fig. 3). The daily mass specificthermoregulatory cost was calculated 60. from Eqs.1-4, and assumedno brooding by the parentsand a body temperatureof 39øCmain- tainedby the chicks(Klaassen et al. 1989).Mass 40- specificthermoregulatory costs decreased rap- idly over the first 7 days.From an age of ca. 10 days onwards, thermoregulatorycosts stabi- lized around 0.6 kJ.g-•.day-' (Fig. 4). ß v v 6• Total energy'expenditure of the chicks, in- • ß f10 cluding basal metabolism, biosynthetic and thermoregulatorycosts as well as costsfor ac- tivity, was estimatedby DLW. Carbon dioxide 0 productionby chicks,calculated from the mea- suredoxygen consumption by indirect calorim- etry, was systematicallyhigher than measured by DLW (Table 1). This underestimationof the metabolicrate using DLW was lesspronounced in the first(samples 1 and 3) thanin the second (samples2 and 4) partof the experiment.The errors were -4.5% (SD = 2.4) and - 16.0% (SD v'vß vvAGE KNOWN = 9.0) for the firstand second part, respectively. The field estimatesof CO2production from DLW 16 16 ADULT age, days showed the same relatively low values for ex- perimentsstarted half a day after injectionof Fig. 2. Water contentas percentageof total body the isotopes(Table 2). After correctingfor the mass(A), lipid mass(B), lipid-free dry mass(B), and underestimations,the total energyexpenditure energy content (C) of 11 Arctic Tern chicks and 2 in the field (Fig. 5) was describedby: adults as a function of age. Ea,• = 9.70(t + 1)'.'7ø kJ/day (7) actual thermal environment, measured as Te, and the relation between Ta and oxygen con- (r = 0.988, n = 16, P < 0.001). sumption establishedin the laboratory (Klaas- The costsof activity (Eat,)were calculatedby sen et al. 1989). Ambient temperatures in Ny subtractionof basalmetabolic, biosynthetic and .•lesundwere relatively stable and ranged be- thermoregulatory costsfrom the total energy tween 3.4 and 9.0øCover the investigation pe- expenditure as measuredwith DLW. riod. In contrast,the operativetemperature vat- We reconstructed total energy requirements
TABLE1. Validation of the doubly labeled water technique.Comparison of CO2 productionestimates from doubly labeledwater experimentsand indirect calorimetry.
CO2 production (retool/ day) Indirect Error (%) Individual Age (days) Initial mass(g) Massgain (g) DLW calorimetry DLW 544 5.5 41.0 6.2 151 159 -5.0 544 6.0 42.6 5.5 128 173 -26.0' 521 13.0 74.0 8.2 303 309 -2.0 521 13.5 69.4 16.5 289 334 - 13.5' 502 19.0 109.0 -1.6 283 303 -6.6 502 19.5 108.0 -5.1 267 292 -8.6'
Carbondioxide productioncalculated over the secondpart of the experiment,see text, 244 KLAASSENETAL. [Auk,Vol. 106
o Tedeardays
20'
10.
time of the day, h
Fig. 3. Daily ambient and operativetemperature (___SD) for clear (cloud cover -< 4/8) and cloudy (cloud cover> 4/8)days, at theArctic Tern colony in Ny ,•,lesund,Svalbard, between 12 July and 6 August1086.
(Er,q)of Arctic Tern chicksas a functionof age are included in the "hatchling" BMR, the dif- by integratingthe data on energy costsof basal ference between total energy expenditure as metabolism, biosynthesis, thermoregulation, measuredby DLW and BMR during the first 3 activity,total energyexpenditure and tissuede- days of age was assumedto consistof additional position (Fig. 6). costsfor synthesisin nonstarvedhatchlings. The complete separation of BMR and costs A secondcomplication in reconstructionof for biosynthesisin young chickswas not pos- the energy budget was that during the first 11 sible.Hatchlings which still containyolk, even days,total energyexpenditure (as calculated by when they are starved before BMR measure- the summationof BMR, synthesis,and ther- ment, continuetissue growth, usingthe yolk as moregulation) exceededthe energy expendi- a source for metabolites (Klaassen et al. 1987). ture estimated by DLW. This overestimate of Becauseit is unclearwhether all syntheticcosts 456 kJ or 26%of E,• wasat leastpartly due to excluding the brooding behavior of the parents from the energy budget. During the first week after hatch, the chicks were thermolabile
DLW estimates ?50 -
700-
150-
100-
age, days 50- Fig. 4. Thermoregulatorycosts as a function of age,calculated from operationaltemperature and lab- oratory-establishedrelations between temperature and o 6 lb age. days oxygen consumption.Indicated variation (+SD) ex- pressesvariation in measuredoperative temperatures Fig. 5. Total energy expenditure measuredwith (seeFig. 3). Shadedarea representsthe estimatedac- doublylabeled water, of free-livingArctic Tern chicks tual thermoregulatorycosts after accountingfor pa- asa function of age.The correctedvalues are plotted rental brooding (see text). (see Table 2). April1989] ChickGrowth and Energetics 245
T^nLE 2. Field estimates of CO2 production with 400' doubly labeled water.
C02 production 300- Initial Mass (retool/day) Indi- Age mass gain Uncor- Cor- 200- vidual (days) (g) (g) rected rectedb 12 0.5 12.7 3.8 22 23 12 1.0 15.1 1.5 36" 43 100- 89 1.5 16.5 4.5 56 59 BMR 79 1.5 14.4 0.0 45 47 79 2.0 14.3 0.3 53 a 63 1 2.5 17.9 2.0 48 a 57 øo 16 2b 120 4.5 35.0 12.0 147 154 age, days 120 5.0 45.3 13.5 131" 156 Fig. 6. Total energy requirements(E•q) of free- 86 6.5 45.2 5.3 192 201 livingArctic Tern chicks in Ny ,•lesund,Svalbard, 86 7.0 48.5 12.0 170 • 202 58 8.5 61.9 8.6 245 257 from hatching until flectging.Total energy expendi- 58 9.0 64.5 8.5 213" 254 ture measuredby DLW (Ea•w)is partitioned in BMR, 56 10.5 81.0 1.0 349 365 tissuesynthesis (E•y,), thermoregulation (E,h), and costs 56 11.0 80.0 4.0 261 a 311 for activity (Eact).The accumulationof body tissue 86 16.5 97.0 6.0 342 • 407 completesthe total energy requirements. 58 18.5 109.0 3.0 453 474
"Carbon dioxide productioncalculated over the secondpart of the experiment, see text. (Klaassenet al. 1989) and were nearly contin- bCorrected according to the estimatederrors for first and secondpart uouslybrooded by the parents(Busse 1983). In of DLW experiment,as determinedin validation experiment. the second and third week after hatch, the par- entsmay still broodor sheltertheir chicks,at least during periods of rain (Busse1983). The Nagy 1985,Williams and Prints 1986).Williams thermal model is static,and not capableof se- and Nagy (1985) arguedthat an underestimate lecting the most favorablemicroenvironment. of CO2production measured by DLW resulted Althoughwe aimed for the mostfavorable site from the incorporation of hydrogen but not for our measurement,this technique probably oxygen into newly synthesizedtissue. Assum- underestimated the actual T• encountered by ing the "worst case"scenario for the Savannah chicks in the field even when not brooded by Sparrow nestlings (Passerculussandwichensis), the parents.Therefore, during the first week, Williams and Nagy (1985) calculateda possible thermoregulatorycosts were assumed to be close underestimateof Edlwby 25%. In the Arctic Tern to zero, and increasedonly graduallyuntil Day chicks,measured error was up to -16.0% and 11 (Figs.4, 6). well outsidethe rangeof +8% generallyfound The calculatedenergy budget of Arctic Tern in validation experimentsin animalswith fairly chicks reveals that total energy requirements stablebody mass(Masman and Klaassen1987). over the first 21 days of age amount to 4,442 Carbon dioxide production measurements kJ/chick. Of the total energy requirements42% showedthat during the experimentthe under- is allocated to basal metabolism, 8% to biosyn- estimationbecame more pronounced.This sug- thesis,18% to thermoregulation,9% to activity, gestsan increasingincorporation rate of deu- and 23% to tissue deposition. terium during the experiment. In the absence of more detailed studies we assume our pro- DISCUSSION cedure and corrections are valid. The total energy requirementsof Arctic Tern The use of DLW in rapidly growing animals chickschanged dramatically during the second may lead to severeerrors in estimatesof total week. At this point the tarsuswas virtually full energyexpenditure, due to irreversibleand dis- grown (Fig. lB), which indicatesadvanced lo- proportional incorporationof the isotopesin comotorycapacity. This was confirmedby the body tissue (Nagy 1980, Williams and Nagy contributionof activity coststo the total energy 1985), although the method has been used expenditureat Day 11. Furthermore,chicks were widely (Fiala and Congdon1983, Williams and capableof thermoregulationat fairly low costs. 246 KLAASSENET AL. [Auk, Vol. 106 •200t Arctic Tern J I CommonTern I I SootyTern
Efts 160- 80 iili•.!••.•:..• BMR+Eth ' 2• ' • ' 1•) ' 2• ' 3• •) 1•3 2'0 ;•0 4•) 5'0 age,days Fig.7. Growthcurves and energy requirements of Arctic,Common, and Sooty terns. Energy requirements werecompiled from costs for tissueaccumulation (E,,), tissue synthesis (Esyn), and basal metabolism plus thermoregulation(BMR + E,h).Energy requirements for activityare excluded.
The favorabledevelopment of both locomotory spectively.Therefore, we assumedthermoreg- and thermoregulatorycapacities reduced the ulatorycosts were lower for both Commonand need of parental attention, and left more time Sootytern chicks.The differencebetween en- for the parentsto forage.This changeoccurred ergy requirementsof Commonand Arctic tern when the chick had reached half of its maxi- chickswas mainly a result of the differencesin mum energyrequirement level. For the chick, thermoregulatorycosts, which never exceeded thesechanges might be consideredas a change 0.73 times BMR or 21% of the total energy re- from an altricial to a more precocial mode of quirementsin ArcticTern chicks.The valuesof life. 21% and 18% of Er.q for maximumand mean To evaluate the effect of the arctic environ- thermoregulatorycosts may be slightly higher ment on total energy requirements, we com- than the actual values because of underesti- paredthe ArcticTern chickenergy budget with mation of T, (seeabove), and the possibleeffect the budgetsof two related speciesstudied at of endogenousheat productionduring activity different latitudes(Fig. 7). CommonTerns were on thermoregulation.The heat incrementof studied on Great Gull Island, New York (41øN, feedingdid not substitutefor thermoregulatory 74øW),and the Sooty Terns on Bush Key, Dry costsin Arctic Tern chicks(Klaassen et al. 1989). Tortugas, Florida (25øN, 81øW; Ricklefs and In the Arctic Tern chick, there appear to be White 1981).Activity costswere excludedfrom mechanisms to reduce thermoregulatory re- the comparisonas they are unavailablefor the quirements.Fat contentin Arctic Tern chicks Common and Sooty tern. Arctic and Common was high (about28% of wet body mass)com- tern grow rapidly and have similar growth paredto Commonand Sooty tern chicks(about curves.The patternsof energy requirementsas 22%; Ricklefs and White 1981). Fat reserves a function of age are also similar. Energy ex- might increaseinsulation and serveas an en- penditure and depositionincrease through the ergy reserveduring periodsof bad weather.A midpoint of developmentwhen, becauseof re- high metaboliccapacity would alsobe benefi- duced tissue accumulation, they decrease cial in arctic environments to ensure enough slightly. The Sooty Tern grows slowly, with endogenousheat productioncapacity for ther- continuously low daily energy requirements moregulation.The basalmetabolic rate might during development. indicate the metabolic capacity,and BMR in Ambient temperatureson Great Gull Island ArcticTern hatchlingsis indeedrelatively high and BushKey were 25øCand 35øCduring the comparedwith relativesfrom lower latitudes day, and 17øCand 27øCduring the night, re- (Klaassen et al. 1989). April 1989] ChickGrowth and Energetics 247
Thus Arctic Tern chicksseem to be well pre- sequencesof sexualsize-dimorphism in nestling pared for the "cold Arctic" at relatively low Red-winged Blackbirds.Ecology 64: 642-647. extra expenses.However, the energy budgets HILLß R. W. 1972. Determination of oxygen con- used for the comparison(Fig. 7) do not cover sumptionby useof the paramagneticoxygen an- alyser.J. Appl. Physiol.33: 261-263. all costs.Complete partitioning of the total en- JORGENSEN,E., & A. $. BLIX. 1985. Is the rate of body ergy requirements can elucidate life history cooling in cold exposedneonatal Willow Ptar- strategiesin related speciesthat reproduce at migan chicksa regulated process?Acta Physiol. different latitudes. Scandinavica 124: 404. KLAASSEN,M., G. $LAGSVOLD,& C. BECH. 1987. Met- ACKNOWLEDGMENTS abolic rate and thermostability in relation to availability of yolk in hatchlingsof Black-legged This studywas supported by grantsfrom the Nor- Kittiwake and Domestic Chicken. Auk 104: 787- wegian Polar ResearchInstitute (30/86) and the Nan- 789. sen Foundation (75/87). We thank the Norwegian ß C. BECH, & G. SLAGSVOLD. 1989. Basal met- authoritieson Svalbard,and the personnelof Kings abolic rate and thermal conductance in Arctic Bay Coal Company and the Norwegian Polar Re- Tern chicks (Sternaparadisaea) and the effect of searchInstitute in Ny ,•lesundfor their help in mak- heat increment of feeding on thermoregulatory ing this studypossible. We acknowledgethe valuable expenses.Ardea 77 (in press). comments of T. L. Brisbin, S. Daan, R. H. Drent, and LEMMETYINEN,R. 1972. Growth and mortality in the an anonymousreferee during preparation of the chicks of Arctic terns in the Kongsfjord area, manuscript. Spitsbergenin 1970. Ornis Fennica 49: 45-53. LIFSON,N., & J. S. LEE. 1961. Estimation of material balanceof totally fasted rats by doubly labeled LITERATURE CITED water. Am. J. Physiol. 200: 85-88. ß & R. MCCLINTOCK.1966. Theory of use of AULIE,A., & J. B. $TEEN.1976. Thermoregulationand the turnover rates of body water for measuring musculardevelopment in cold exposedWillow energy and material balance. J. Theor. Biol. 12: Ptarmiganchicks (Lagopus lagopus L.). Comp. Blo- 46-74. chem. Physiol. 55A: 291-295. MAHER,W.J. 1964. Growth rate and development B^KKEN,G.S. 1976. A heat-transferanalysis of an- of endothermy in the Snow Bunting (Plectro- imals: unifying conceptsand the application of phenaxnivalis) and Lapland Longspur (Calcarius metabolismchamber data to field ecology.J. The- lapponicus)at BarrowßAlaska. Ecology 45: 520- oret. Biol. 60: 337-384. 528. BECH,C., $. MARTINI, R. BRENTß& J. RASMUSSEN.1984. 1VIASMAN,D., & M. KLAASSEN.1987. Energy expen- Thermoregulationin newly hatchedBlack-legged diture during free flight in trained and free-liv- Kittiwakes. Condor 86: 339-341. ing Eurasian Kestrels (Falcotinnunculus). Auk 104: BENGTSON,S.A. 1971. Breedingsuccess of the Arctic 603-616. Tern Sterna paradisaea(Pontoppidan), in the NAGY,K.A. 1980. CO2production in animals:anal- Kongsfjordareaß Spitsbergen in 1967.Norwegian ysisof potentialerrors in the doublylabeled water J. Zool. 19: 77-82. method.Am. J. Physiol.238: R466-R473. BOERSMA,P.D. 1986. Body temperature,torporß and NORTONßD.W. 1973. Ecologicalenergetics of Cali- growth in chicks of Fork-tailed Storm-Petrels dridine Sandpipersbreeding in northern Alaska. (Oceanodromafurcata). Physiol. Zool. 59: 10-19. Ph.D. dissertationß Fairbanks, Univ. Alaska. BOGGS,C., E. NORRISß&J. B. $TEEN. 1977. Behavioural PEDERSEN,H. C., & J. B. $TEEN. 1979. Behavioural and physiological temperature regulation in thermoregulation in Willow Ptarmigan chicks young chicksof the Willow Grouse(Lagopus la- (Lagopuslagopus). Ornis Scandinavica10: 17-21. gopus).Comp. Blochem.Physiol. 58A: 371-372. RICKLEFS,R. E. 1967. A graphical method of fitting BUSSE,K. 1983. Untersuchungenzum Ehe- und So- equationsto growth curves.Ecology 48: 978-983. zialleben der Kuestenseeschwalbe(Sterna parad- 1974. Energeticsof reproduction in birds. isaeaPONT.) mit besonderer Berueksichtigung Pp. 152-297 in Avian energetics(R. A. Paynter des lang zeitlichen Wandels der individuellen Jr., Ed.). CambridgeßMassachusettsß Nuttall Or- Beziehungen. Ecol. Birds 5: 73-110. nithol. Club. CHAPPELL,IV•. A., D. L. GOLDSTEIN,& D. W. WINKLER. ß& $. C. WHITE. 1981. Growth and energetics 1984. Oxygen consumptionßevaporative water of chicksof the SootyTern (Sternafuscata) and loss,and temperatureregulation of CaliforniaGull Common Tern (S. hitundo). Auk 98: 361-378. chicks (Laruscalifornicus) in a desert rookery. T^YLOR,J.R.E. 1985. Ontogenyofthermoregulation Physiol. Zool. 57: 204-214. and energy metabolismin PygoscelidPenguin FIALA,K. L., & J. D. CONGDON.1983. Energetic con- chicks.J. Comp. Physiol. 155B:615-627. 248 KLAASSENET AL. [Auk, Vol. 106
WALSBERG,G. E., & W. W. WEATHERS.1986. A simple --, & A. PRINTS.1986. Energeticsof growth in techniquefor estimatingoperative environmen- nestling SavannahSparrows: a comparisonof tal temperature.J. Term. Biol. 11: 67-72. doubly labelled water and laboratoryestimates. WILLIAMS,J. B., & K. A. NAGY. 1985. Water flux and Condor 88: 74-84. energeticsof nestlingSavannah Sparrows in the field. Physiol.Zool. 58: 515-525.
The Frank M. ChapmanMemorial Fund givesgrants in aid of ornithologicalresearch and alsopostdoctoral fellowships.While there is no restrictionon who may apply, the Committeeparticularly welcomes and favors applicationsfrom graduate students;projects in game managementand the medical sciencesare seldom funded. Applications are reviewed once a year and must be submitted no later than 15 January,with all supportingmaterial. Applicationforms may be obtainedfrom the Frank M. Chapman Memorial Fund Committee,Department of Ornithology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA. There were no Chapman Fellowshipsawarded for 1988. Chapmangrants for 1988,totaling $43,954.00, with a meanof $698.00,were awarded to: Juan Amat, moulting ecologyof the Red-crestedPochard (Netta rufina)in Spain;Gonzalo Arango, la taxonomiay las distribucion del generoThamnophilus en Colombia;Todd W. Arnold, proximateand ultimateconstraints on clutchsize in American Coots;John M. Bates,winter survivorshipin the House Sparrow (Passerdomesticus): a morphologic andallozymic perspective; Douglas A. Bell,hybridization between the WesternGull andthe Glaucous-winged Gull; William L. Benner,range expansion and rapid evolutionin the HouseFinch Carpodacus mexicanus; Robert E. Bleiweiss,biochemical systematics of hummingbirdsusing DNA-DNA hybridization;William I. Boarman, environmentalcomponents of selectionon avian song;Rhys V. Bowen, evolutionarysignificance of inter- specificforaging competition;Reed Bowman,mediation of asynchronoushatching and brood reductionin White-crownedPigeons; James V. Briskie, dynamicsand consequencesof copulationpatterns in Smith's Longspur;Neil J. Buckley,role of informationtransfer in the foragingbehavior of Turkey VulturesCathartes aura;Carolee Caffrey, cooperative breeding in AmericanCrows: do helpershelp?; Angelo P. Capparella, geneticdifferentiation among Patagonian birds in secondarycontact; Jose Maria Cardosada Silva, taxonomic studies of birds collected in Urucum and Corumba, Brazil; Kevin Cash, brood reduction in Swainson's Hawk; Glen Chilton, discriminationof dialectsby female White-crownedSparrows; Carla Cicero,variation in the songof the Lincoln'sSparrow (Melospiza lincolnii) in California;Thomas Peter Coorobs-Hahn, environmental controlof reproductivephysiology in the RedCrossbill; Donald A. Croll, diving and energeticsof the Murre; TimothyCrowe, systematics of Galliformes,Raptors, Bustards and Larks; Robert W. Dickerman,ornithological explorationof Upper Guinea lowland forestrefuge; Katherine E. Duffy, the migration of owls at Cape May Point, New Jersey;David Enstrom,continuing investigation of delayedplumage maturation in Orchard Orioles;B. PatriciaEscalante-Pilego, geographic variation in Geothlypisof Baja,California, and westernMexico; Mary C. Garvin, the role of blood parasitesin mechanismsof avian sexualselection; Stephen M. Gatesy,a functionalstudy of avian terrestriallocomotion; Rosemarie Gnam, breeding biology of the BahamaAmazon (Amazonaleucocephala bahamensis); Pedro C. Gonzales,study of AMNH collectionof Palawanbirds; Martha Groom, detrimentsof nesting successand nest-siteselection in four beach-nestingbird species;Percy N. Hebert, asynchronoushatching and parentalinvestment in the Yellow Warbler (Dendroicapetechia); Geoffrey E. Hill, female mate preferencein relation to male carotenoidpigmentation in the House Finch; Sylvia Hope, geographicvariation in callrepertoire of the Steller'sJay; L. ScottJohnson, the functionof territorialintrusions and mateguarding in HouseWrens; Ian L. Jones,the evolutionof socialsignals of the seabirdgenus Aethia; Michael C. Kaspari,experiments with overwinteringmixed speciesflocks in the SonoranDesert; Mary Katz, song variation in Pardalotusstriatus, and its relationshipto morphologicalvariation; L. Henry Kermott, ec- toparasitismof nestlingHouse Wrens by Protocalliphorabraueri (Diptera); Nedra Klein, geographicvariation and systematicsof the Yellow Warbler;Natasha B. Kotliar,a hierarchicalconcept of patchiness:implications for the foragingbehavior of nectarivorousbirds; David S. Lee, systematicsof seabirdsfrom North Carolina and the Philippines;Bruce Lyon, ecology and evolutionof intraspecificbrood parasitism in AmericanCoots; RandallJ. Mitchell, the effectof nectarrewards on hummingbirdbehavior and pollen depositionand dispersal; David C. Oren, avifauna of Maranhao State,Brazil; David Pashley,distribution of wood warblers in the Neotropics;A. TownsendPeterson, evolutionary relationships of the AphelocomaJays; Don Roberson,research on Pterodromain AMNH collection;Frank G. Rozendaal,systematics of Asian-Pacificbush-warblers of the generaCettia, Urosphena, Tesia and Bradypterus(Aves: Sylviidae); Karl-L. Schuchmann,behavior and repro- ductionbiology of the Tooth-billedHummingbird (Androdon aequatorialis); Gilles Seutin, mechanism of species
(continuedon p. 278)