If by Pakshik Parv you mean Pakhi Pratikraman in Jain tradition, then in May 2026 it falls on:

• May 1, 2026 — Purnima
• May 16, 2026 — Amavasya
• May 31, 2026 — Purnima

Pakhi is observed twice in a lunar month, on the fortnight-end days. The exact observance can vary a little by local panchang and sect tradition. ( jainknowledge.com)