Abstract: Compounds of formula (I), wherein X.sup.1 and X.sup.5 are each separately selected from hydrogen and C.sub.1-4 alkyl, halogeno and halogeno-substituted C.sub.1-4 alkyl groups: X.sup.2, X.sup.3 and X.sup.4 are each separately selected from hydrogen and C.sub.1-4 alkyl, hydroxy, C.sub.1-4 alkoxy and phenoxy groups; R.sup.1 and R.sup.2 are each separately selected from hydrogen and C.sub.1-4 alkyl groups; R.sup.3 and R.sup.4 are each hydrogen or together constitute the second bond of a carbon-carbon double bond joining --CR.sup.1 R.sup.3 and --CR.sup.2 R.sup.4 ; and Y is hydroxymethyl, formyl, cyano, carbamoyl, carbamoyl N-substituted by one or two of the same or different C.sub.1-4 alkyl groups, carboxy or a carboxylic ester or carboxylate salt, are of value as avian repellents.