Experimental manipulation of testosterone levels in male Red-winged
Blackbirds (Agelaius phoeniceus) and resulting changes in antibody
levels
Arguments
source
Hasselquist, D., J.A. Marsh, P.W. Sherman, and J.C. Wingfield. 1999.
Is avian immunocompetence suppressed by testosterone? Behavioral
Ecology and Sociobiology 45: 167-175.
Blackbirds
xyplot(log.after ~ log.before, data = Blackbirds,
ylab = "log Antibody production after implant",
xlab = "log Antibody production before implant")