000			01523nab a22002777u 4500
003			EC-PaCDF
005			20241003112232.0
008			060603t19811981||||||||||||||||||||eng||
040			_aEC-PaCDF _bspa
041			_aeng
082	0	4	_a598.883 _222
100	1		_aGrant, P. R. _91888
245	1	4	_aThe feeding of Darwin's finches on Tribulus cistoides (L.) seeds / _cP. R. Grant.
260	3		_c1981.
520			_aFood-handling skills of finches vary as a function of bill size. Geospiza magnirostris crush and shatter the woody mericarps of caltrop (Tribulus cistoides) to reach the seeds, whereas G. fortis (a smaller species) bite and tear at them. G. magnirostris accept and crack most of the mericarps picked up; fortis reject most mericarps but often feed on fragments. Energy rewards are greater for magnirostris than for fortis. Intraspecific variation in handling skills parallels interspecific variation. G. fortis individuals with large bills spend more time on mericarps and extract more seeds than do those with small bills, and they reject mericarps with a lower frequency. Those observed feeding on seeds from Tribulus mericarps were larger, particularly in bill size, than those not observed feeding on them.
546			_aInglés
653			_aDarwin's finches
653			_aPinzones de Darwin
653			_aGeospiza
653			_aSeeds
653			_aSemillas
653			_aTribulus cistoides
653			_aGalápagos
773			_tAnimal Behaviour, 1981, 29, 785-793.
942			_2ddc _cARTICLE
999			_c1272 _d1272