Pikitia signed the Tauranga sheet of the Treaty of Waitangi at Tauranga in April or May 1840.
For further information and sources see Debbie McCauley, The Treaty of Waitangi in Tauranga: Te Tiriti o Waitangi ki Tauranga Moana: https://debbiemccauleyauthor.wordpress.com/heritage/cultural-heritage/te-tiriti-o-waitangi-ki-tauranga-moana-treaty-signatories