package metafor: error when setting 'col' and 'at' for a forest plot

I am using metafor to create forest plots. This code gives me the expected
plot (setting x axis tick marks):

forest(forest$OR, ci.lb=forest$Low, ci.ub=forest$High,  at=log(c(.05, .25,
1, 10)), slab=forest$SNP, atransf=exp)

As does this (setting colors):

forest(forest$OR, ci.lb=forest$Low, ci.ub=forest$High,  col=c(1,2,3),
slab=forest$SNP, atransf=exp)

But if I try to set both 'at' and 'col':

forest(forest$OR, ci.lb=forest$Low, ci.ub=forest$High,  col=c(1,2,3),
at=log(c(.05, .25, 1, 10)), slab=forest$SNP, atransf=exp)

I receive this error:
Error in polygon(x = c(alim[2], alim[2] - (1.4/100) * cex * (xlim[2] -  : 
  formal argument "col" matched by multiple actual arguments

Any help greatly appreciated.

Brian Z Ring PhD
Professor, Director
Institute of Personalized and Genomic Medicine
College of Life Science
Huazhong University of Science and Technology
Wuhan, ?China