House Finches typically have a red bandana or headband. However, sometimes the color can be orange or even yellow.
Unfortunately, House Finches are prone to mycoplasmal conjunctivitis. If you have House Finches in your area, Cornell has a House Finch Disease Survey you can fill out to help researchers track the spread of the disease. To see what conjunctivitis looks like, go to Cornell's Photo Gallery.
Read more about House Finches and why they were called "Hollywood Finches" or why they changed color when they were brought into Hawaii.
House Finches and Purple Finches are often misidentified by the beginner birder. See a side-by-side comparison of a House Finch and Purple Finch in Bird 101.