Finished up my Hairy and Downy woodpeckers. I will be using this illustration to show the differences between these two species, so look for that soon! Faber-Castell Polychromos colored pencil (with some Prismacolor white) on 9″x12″ Stonehenge paper.
There are a few ways to tell apart Downy and Hairy Woodpecker!
Size of the bird is one. If it’s coming to a feeder, for instance one of those small suet cages, you may be able to judge the overall size. Here is a comparison of both species at once (!) on one of those suet cages:
Proportion of the bill is another one. In the above image, both birds’ heads are more or less in profile. You can see how the Downy bill is more like a small thorn and the Hairy has a monster schnoz nearly the size of the rest of its head! The below drawing is another good comparison:
Tail pattern can be diagnostic. Downy woodpeckers have black barring on their outer tail feathers. If the feathers have no black spots, it’s a Hairy. This can be hard to see unless the bird’s tailfeathers are spread while perching. Downy on the left, Hairy on the right:
Head pattern might be a way to tell males apart. In a 2011 blog post, Sibley describes the presence of a black bar through the red patch as diagnostic of Hairy Woodpecker. Its absence is not a clue for Downy- the feathers can fluff up and hide it. Also, about 1% of Downy Woodpeckers might have this.
Finally, you can use sound to tell them apart. Downy Woodpecker’s call is more of a “Pik! Pik!” to the Hairy Woodpecker’s lower, more emphatic “Peek! Peek!”
You can listen to calls for Downy and Hairy and view comparisons on Cornell’s AllAboutBirds website, too.