I think this is a yellow rumped Warbler
A little dark but colour is greyish.
At least five observed.
Red-eyed Vireo. Song. Recorded at MapleCross Coastline Reserve, Prince Edward County, Ontario on 28 June 2021.
Clay-colored Sparrow. Song. Recorded at MapleCross Coastline Reserve, Prince Edward County, Ontario on 28 June 2021.
Yellow Warbler. Song. Recorded at MapleCross Coastline Reserve, Prince Edward County, Ontario on 28 June 2021.
Mourning Dove. Song. Recorded at MapleCross Coastline Reserve, Prince Edward County, Ontario on 28 June 2021.
Song Sparrow. Song. Recorded at MapleCross Coastline Reserve, Prince Edward County, Ontario on 28 June 2021.