It's a male goose. Most of us today don't make a distinction between a female goose and a male goose, but historically, a gander was the male, a goose the female. (Goose also doubled as the general name for the bird, which may be why gander became less well-known over time.)
With the change in weather there will come an opportunity to stimulate controlled growth. The saying, “What is good for the goose is good for the gander.” states that something that is good for one should be good for all.