He skipped social gatherings so that he could rise early and go into the countryside to lie motionless for hours, hidden behind reeds at the water's edge.
Occasionally he brought a gun, saying "Sometimes I have to kill these birds and animals in order to dissect and study their structure." But he needed to see them up close and alive to understand their postures and movements.
He tried sketching at zoos, but found that "the modified captivity of the animals distorts their character and changes their habits."
He created his own menagerie in Uppsala, Sweden with more free-roaming spaces, but even there he found they acted unnaturally—especially the fox, who he wanted most to observe.
So one day he decided to set the fox free.
"When he turned his fox loose he gave him a fair start over his hounds, intending to have a fox-hunt all to himself; but the fox waited quietly for the dogs to come up with him, and then they played together. It was a failure, even from an artistic point of view."Quotes from Brush and Pencil, Vol XV, June 1905.