Feeding deterrence in the seed-eating sparrow Zonotrichia capensis against common seed phenols

JUAN MANUEL RÍOS; ANTONIO MANGIONE

San Luis

Congreso; Reunion Sociedad Biología de Cuyo; 2009

Some allelochemical compounds such as phenolic secondary compounds (PSC´s) include deterrent activity against seed-eating animals. Birds have the ability to recognize such compounds and can circumvent the intake avoiding the adverse effects. Zonotrichia capensis it is a highly opportunistic wild bird with an ample diet breath, since it feeds on different kinds of weed seeds many of them with PSC´s. We test the hypothesis that this sparrow is able to avoid different kinds of phenols in relation to the particular phenol´s chemical structure. We realize two-choice feeding trials in the laboratory in order to evaluate the effects of topical application with solutions at 1% of PSC´s common in seeds. Only those compounds that turned out to be deterrents were re-evaluated to a minor concentration of 0.5%. The PSC´s evaluated were the high molecular weight phenols: tannic acid =TA and condensed tannins =CT and the low molecular weight phenols (phenylpropanoids): cinnamic acid =CA; cafeic acid =CfA and ferulic acid =FA. Z. capensis avoided significantly seeds topically applied with TA, CA and CfA at both concentrations and did not avoid the seeds topically applied with 1% of CT and FA. These results suggest that this sparrow rejects the phenols according to the particular chemical structure.