I believe this is raccoon scat, although I'm not certain on the size of the scat and if it's much larger than I'm thinking (i.e., about 4-5" long and 0.5" wide), I suppose it could be black bear scat. Having a raccoon scat on your deck is more likely than a bear, just in terms of their behavior (foraging around human settlements) and their abundance. 

Regarding it being the size of a dog's scat, I'm not sure if that's a large dog or small dog breed, so I'm a bit hesitant to commit to how large this scat really is.  Raccoons and black bears both eat a lot of berries and their scats can look similar except for size. 

These links may be helpful in determining the animal if you can measure the size (length, width).

https://www.michigan.gov/-/media/Project/Websites/dnr/Documents/Education/NatureHome/MI_Scat_Dichotomous_Key_images.pdf?rev=fa060a583a0e4fe2896d16b9c8116893

https://bear.org/scat-droppings/

https://www.crittercontrol.com/wildlife/raccoons/raccoon-droppings

https://nature-mentor.com/raccoon-scat/#:~:text=Raccoon%20Scat%20Identification%3A%20What%20Does,to%207%20inches%20in%20length.

Also be aware that raccoon scat can carry several diseases transmissible to humans so pleas take caution when removing this scat and cleaning the area.

I hope this helps.

Best,