An evaluation of methyl anthranilate, aminoacetophenone, and unfamiliar coloration as feeding repellents to American Kestrels

---A comparison of methyl anthranilate and 4-aminoacetophenone as feeding repellents to a captive colony of American Kestrels (Falco sparverius) was made to determine whether aversive conditioning to these chemicals is possible in a bird of prey species. Our results suggested that, while these chemicals seemed to cause some food rejection by kestrels, they did not deter them from eating treated dead, day-old cockerels. A second study using a combination of chemical additives linked to food dyed an unfamiliar color revealed that color, and not the chemicals, was a more aversive agent. This suggested that manipulation of a kestrel's visual perception of a prey item alone had potentially more success than conditioning it to avoid a chemical additive. These results may prove useful in practical applications such as protecting game bird young at wild release sites or domestic homing pigeons associated with a particular home loft. These measures may in turn help to protect birds of prey from persecution as competitors for prey of human economic importance. I•3⁄4 WORDS: American Kestrel; Falco sparverius; conditioned taste aversion; CTA; food choice,, appetite suppressant; visual perception; aposmatic coloration. Metyl antranilato, aminoacetofen y la coloracion inusual coxno repelentes alimenticios de Falco sparverius RESt•MEN.--Una comparacifn de metil antranilato y 4 aminoacetofen como repelentes alimenticios de una colonia en cautiverio de P•lco sparverius fue utilizada para determinar si un acondicionamiento de aversifn a estos quhnicos es posible en una especie de ave rapaz. Nuestros resultados sugieren que mientras estos quimicos pudieron haber causado algun tipo de rechazo por los cernicalos, esto no los detuvo de alimentarse de pollos muertos de un dia de nacidos. Un segundo estudio utilizando una combinacifn de aditivos quimicos ligados a una comida tefiida de un color inususal, revel6 que el color y no los quimicos obraron mas coxno agente de aversifn. Esto sugiri6 que la manipulacifn de la percepcifn visual de una presa tuvo potencialmenmte mas axito que el acondicionamiento para evitar los aditivos quimicos. Estos resultados pueden ser fifties en la aplicacifn pr/tctica como en la proteccifn de juveniles de aves de caza en los sitios de liberacifn o de palomas mensajeras asociadas a ciertos sitios. Estas medidas pueden a la vez ayudar a proteger alas aves rapaces de la persecuci0n como competidoras de presas de importancia econfmica. [Traduccifn de Cfsar M/trquez] Although charismatic and often of high conservation priority, birds of prey are regarded as pests when taking prey of human economic interest, such as when Peregrine Falcons (Falco peregrinus) take domestic pigeons (Columba livia) (Ratcliffe 1993), Hen Harriers ( Circus cyaneus) and other raptors kill Red Grouse (Lagopus lagopus) (Redpath and Thirgood 1997), and Northern Goshawks (Accipiter gentills) kill Ring-necked Pheasants (Phasianus colchicus) (Kenward 1977). Such conflicts of interest have resulted in the illegal killing of birds of prey (Cadbury 1992, Etheridge et al. 1997). Musgrove (1997) has suggested the use of aversive conditioning to chemical deterrents as an acceptable (in the sense of Liss 1997) way of reducing Peregrine Falcon predation on pigeons and his pilot studies have shown that methyl anthranilate mixed with food causes vomiting in several falcon species, and so was presumably potentially aversive. Limitations of methyl anthranilate application in