528 SHORT COMMUNICATIONS temperature so that additional energyis not required. Ul- CASE, R. M., AND R. J. ROBEL. 1974. Bioenergeticsof timately, however, a net increase in existence energy re- the bobwhite. J. Wildl. Manage. 38:638-652. quirements will necessitateincreased energy intake and/ IRVING,L., G. C. WEST,AND L. J. PEYTON. 1967. Winter or metabolism of stored energy reserves. No significant feeding program of Willow Ptarmigan shown weight change occurred for the evaluated in this by crop contents. Condor 69169-77. study,indicating minimal net metabolism of storedenergy KENDEIGH,S. C. 1949. Effect of temperature and season during the 30-day study period and primary reliance on on energy resourcesof the English Sparrow. Auk 66: increasedenergy intake. 113-127. Maximum daily temperature (Fig. 1) had a markedly LAPICQUE,L., AND M. LAPICQUE.1909. Consommations better correlation with food consumption than did mini- alimentaires d’oiseaux de grandeursdiverses en fonc- mum or mean daily temperatures. This discovery is sig- tion de la temperatureexterieure. Compte Rendu Sot. nificant in view of previous studies that have dealt only Biol. 66~289-292. with constant or mean daily temperatures. As a possible LARGUIERDES BANCELS, J. 1902. De l’influence de la explanation, we suggestthat during the night, when daily temperature exterieure sur la ration d’entretien chez minimum temperatures normally occurred, the Chukars l’oiseau. Compte Rendu Sot. Biol. 54:162-164. were mostly inactive and may have lessenedphysiological LAUDENSLAGER.M. L.. AND H. T. HAMEL. 1977. Envi- temperature stress, as do many other avian species, by ronmental temperature selection by the chukar par- seeking shelter, fluffing feathers, slightly lowering body tridge (Alectorischukar). Physiol. & Behav. 19:543- temperatures, and/or huddling in groups (Welty 1962). 548. Also, they may have filled their crops during the day to OWEN, R. B. 1970. The bioenergeticsof captive Blue- provide an energy source for utilization during the night winged Teal under controlled and outdoor conditions. as has been reported for Willow Ptarmigan (Irving et al. Condor 72:153-163. 1967). During the daylight hours, however, when maxi- PALADINO,F. V., AND J. R. KING. 1984. Thermoregu- mum daily temperaturesgenerally occurred, the Chukars lation and oxygen consumption during terrestrial lo- spent a considerableamount of time engagedin foraging comotion by white-crowned sparrows Zonotrichia and other activities, and were lessable to utilize most low- leucophrysgambelii. Physiol. Zool. 571226-236. temperature behavioral adaptations. Although the heat SEIBERT,H. C. 1949. Differences between migrant and increment generatedby locomotory activity may have par- non-migrant birds in food and water intake at various tially substituted for the daytime thermoregulatory re- temperaturesand photoperiods. Auk 66: 128-153. quirement (Paladin0 and Ring 1984), temperature-related VERBEEK,N.A.M. 1964. A time and energy study of the energyexpenditures were probably greaterduring the day- Brewer’s Blackbird. Condor 66~70-74. time than at night; hence, the greater correlation of max- WELTY,J. C. 1962. The life of birds. W. B. Saunders imum daily temperature with food intake. Under excep- Co., Philadelphia. tional circumstances where minimum temperature WEST,G. C. 1960. Seasonalvariation in the energybal- extremes occur during daylight hours (e.g., daytime storm ance of the Tree Sparrow in relation to migration. front) the correlation may not hold. In addition, the re- Auk 77~306-329. lationship may lose significanceas temperaturesapproach WEST,G. C. 1968. Bioenergeticsof captive willow ptar- levels which are non-stressfulto the . migan under natural conditions. Ecology 49: 1035- The authors thank the Utah Division of Wildlife Re- 1045. sourceswhich provided the birds, feed, and facilities. LITERATURE CITED

CAIN, B. W. 1973. Effect of temperature on energy re- quirements and northward distribution of the black- bellied tree duck. Wilson Bull. 85:308-317.

The Condor88528-529 0 The CooperOrnithological Society 1986

INFANTICIDE IN THE ’

HAVA GOLDSTEIN,DAN EISIKOVITZ,AND YORAMYOM-TOV Department of Zoology, Tel-Aviv University,Tel-Aviv,

Key words: ; Palestine sunbird; interpreted by Wilson (1975) as enabling the performer to osea. securemating opportunitiessooner than would be possible ifthe female’s offspring(unrelated to the infanticidal male) Infanticide has been reported for many (Hrdy continued to be reared (“sexually selected infanticide,” 1979) and some (Mock 1984) species. Several hy- Hrdy 1974). In his review on the incidence of infanticide potheseshave been suggestedto explain its possibleadap- in birds, Mock (1984) nredicted that sexuallv selectedin- tive value. Killing of young by unrelated adult males was fanticide in birds is much less likely than in , becausemost birds are monogamous.Here we report sim- ilar infanticidal behavior in the Palestine Sunbird (Nec- tarinia osea), a 7-g, monogamous passerinecommon in I Received 10 January 1986. Final acceptance29 April Israel. 1986. In spring and summer, females lay 1 to 3 eggsin a well- SHORT COMMUNICATIONS 529 woven nest that hangs from bushes and tree branches. feeding. At 17:15, we releasedthe territorial male which Incubation and nestlingperiods last 14 and 14 to 20 days, was now color-banded. As soon as it noticed the invading respectively.The youngare fed mostly by the female, while male, the territorial male attackedit. An intensive pursuit the male guards the territory. After fledging, the ensued, where mostly the territorial male followed the feed the young outside the nest for several days, but the invading one, interrupted at times by active fighting. It young and the female stay in the nest for several nights continued until dusk (19:20) at which time the female after fledging. Females whose brood fails, normally stay and the fledglingswere ‘in the’nest and the territorial male in their territories and start building a new nest within 2 was perched on a nearby branch. A day later, we observed to I days. another pursuit of the territorial male by the invading one In Tel-Aviv, Israel, during the breeding seasonsof 1984 (which was now recognizedby the lack of tail feathersdue and 1985, we observed four cases of infanticide or at- to the fighting). tempted infanticide. The first occurred in a three-chick Only territorial males are guaranteedmates in the Pal- nestthat was observedfrom mid-May 1984. The resident estine Sunbird. Unmated males are not uncommon in this male at this nest was color-banded. At 06:30 on 3 June speciesand it seems that whenever a territorial male dis- 1984, the male was not seen in the territory. One fledgling appears, another male replaces him within a few hours was found dead below the nest, another perched about 10 (Goldstein, unpubl.). We suggestthat infanticide by in- m from it and a third was still in the nest. The female was vading males is a mechanism to vacate a territory of the feedina the nerched fledgling:mostlv. At 08:OO an un- progeny of a former male owner in order to obtain the markedmale-appeared. It iewto severalobservation points territory. In this species, females that lose their brood near the nest which were formerly used by the territorial normally remain in their territories and start building new male. When the female tried to feed the fledgling outside nests. Hence, infanticide might enhance mate procure- the nest, the invading male interfered by pulling at the ment. If this is true, infanticide in this speciesis similar female’s tail feathers. When she flew off, the male pecked in form and function to infanticide in mammals, mainly at the fledgling’s head while at times standingon the fledg- in primates and rodents (Hrdy 1977, 1979; Labov et al. ling’s back. When the male came closeto the fledgling,the 1985) and birds suchas Barn Swallows(Crook and Shields latter reactedby makingbegging calls. However, after being 1985), the Purple Martin (Loftin and Roberson 1983), pecked by the male, it made distresscalls and fell to the the Mexican Jav (Trail et al. 1981). the Long-billed Marsh ground. This scenario was repeated throughout the day. Wren (Picman-1977) and the Northern Jacana(Stephens At 18:15, the fledglingentered the nest and fed there until 1982). Both the above and Crook and Shields’s (1985) 18:30 (a few minutes before darkness),at which time the observations show that, contrary to Mock’s (1984) pre- female also entered the nest. At 06:30 on 4 June, one diction, sexually-selectedinfanticide may also occur in fledgling was found dead in the nest without noticeable monogamousbirds. wounds, and the other fledgling was perched outside the We thank Ofer Amir and Tal Vardi for their help in the nest. For 10 observation-hours, the scenario of the pre- field and Linda Romaanano and Do&as W. Mock for vious day continued- the female tried to feed the fledgling while the strangemale (presumably the same individual) their comments on the-manuscript. - attacked the fledgling and interfered with feeding. At LITERATURE CITED 06:30 on 5 June, the fledgling was found dead in the nest, with neck marks on its head and bodv. Pulled feathers CROOK,J. R., AND W. M. SHIELDS. 1985. Sexually se- were also visible. The adults were absent. lected infanticide by adult male barn swallow. Anim. The second observation occurred in a nest that was Behav. 33:754-761. observed from the start of incubation. The adults were HRDY, S. B. 1974. Male-male competition and infanti- not marked. On 29 May, as all three young left the nest, cide among langurs (Presbitisentellus) of Abu, Ra- a strange adult male appeared and attacked one of the jahsthan. Folia Primatol. 22: 19-58. young, which eventually fell to the ground. During the HRDY, S. B. 1977. Infanticide as a primate reproductive attack, another male, presumablythe of the chicks, strategy.Am. Sci. 65140-49. appearedand drove away the invader. HRDY, S. B. 1979. Infanticide among animals: a review, The third observation occurred in a nest that was ob- classificationand examination of the implications for servedfrom the startoflaying on 12 June 1984. Two young reproductive strategiesof females. Ethol. Sociobiol. hatched and grew normally, but on 10 July the resident 1:13-40. male disappeared.On that day a strangeyoung male was LABOV,J. B., U. W. HUCK, R. W. ELWOOD,AND R. J. observed in the territory standing on the traditional ob- BROOKS. 1985. Current problems in the study of servation spots of the territorial male. The young male infanticidal behaviour of rodents. Q. Rev. Biol. 60: was observed attacking the female twice while she tried l-20. to feed one of the young outside the nest. On 15 July, one LOFTIN, R. W., AND D. ROBERSON.1983. Infanticide fledgling was found dead below the nest. We suspectthat by a Purple Martin. Wilson Bull. 95:146-148. the causeof the death was the attacksof the invading male. MOCK.D. W. 1984. Infanticide. . and avian nest- After these three observations, an experiment was at- ling mortality, p. 3-30. In ’ G. Hausfater and S. B. tempted to induce infanticidal behavior. We chose a nest Hrdy [eds.], Infanticide: comparative and evolution- where two, almost fledged young were present. At 13:15 ary perspectives.Aldine, NY. on 29 May 1985, we trapped the territorial male. The PICMAN,J. 1977. Intraspecific nest destruction in the female continued to feed the young in the nest. At 15:50, long-billed marsh wren. Can. J. Zool. 55: 1997-2003. a strangemale appearedand was seennear the nest several STEPHENS,M. L. 1982. Male takeover and possible in- times until dusk. At 06:30 the next day, the female was fanticide by a female northern jacana. Anim. Behav. feeding her young and an adult male was observed near 30:1253-1254. the nest. At 09:30, it began intefering with feeding by TFXL, P. W., S. D. STRAHL,AND J. L. BROWN. 1981. pulling the female’s tail feathers as she fed her chicks. At Infanticide in relation to individual and flock histories 14:15, one of the young came out of the nest and was in a communally breedingbird, the Mexican jay. Am. immediately attackedby the invading male, which pushed Nat. 118:72-82. the fledglingto the ground. At 15:30, both young were out WILSON.E. 0. 1975. :The new synthesis. of the nest, huddled together on a branch. The invading Harvard Univ. Press, Cambridge, MA. male attackedboth youngcontinuously and interferedwith