Why do small birds daily keep pecking in my roof gutters?

I have the same problem. It appears to me after observing them for a while, that they are actually feeding. I have poplar trees around my house and in the fall these trees produce little "helicopter things" that spiral to the ground. (Sorry I do not know what they are actually called). They fall into my gutters and the birds get them and peck the end that contains the seed. I assume they are eating this seed.