Do Barn Swallows help each other build nests?

Question

I have a nest already above my porch and there is another being built (which actually seems sort of late in the season) and I'm wondering if they birds help each other. I walked out and 3 birds were flying around under there. I'm just wondering if it is a community effort since it's such a complex process.

Or, maybe the "extras" are getting ready to lay eggs again. . .

Answer 1

I have a swallow nest in my living room and watched the whole building process from the beginning. Only two birds were involved in the construction, but when the three chicks were able to fly they stayed  close to the nest for a while before flying off.

Answer 2

This might be their 2nd brood (meaning they already had babies successfully leave the first nest and are trying to lay again).  In this case..sometimes the babies from the first nest will help the parents build.  This might be one of their babies you are seeing helping them.