My parents live in Southern New Brunswick and have heard this bird all Summer at all times of the day and night. Unfortunately, it has never come out of the forest for them to snap a picture of it. I was able to capture the sounds it makes the other night and posted it to YouTube. My folks and I would really appreciate any help with putting this mystery to rest.
I suggest you check the call of Tufted Titmouse..... I'm not saying it is your mystery bird but is one that does the Peter, peter, peter call. They have nested in NB. It does not visit feeders until cold weather arrives.
It would be interesting to know what community/area of southern NB your parents live.
I've heard this same call frequently in the woods behind my place as well. It most often calls in the late evening until well after the sun has gone down. Drives me crazy not knowing what it is. :) Hopefully someone can figure it out.
It seems one sound is a Spring Peeper... a small Frog..... yes, will call in daytime and after dark. Despite the name "Spring" Peeper, they can be heard anytime of day/evening+.
I've tried this video several times... have heard something different each time.
Thanks, Ryan. Spring Peeper is the best answer to your query as most birds do not call both day and night.
BTW, I did not suggest Cardinal... one of the many different focuses of that video from YouTube was of a Cardinal.
You are welcome.