In Jainism there is no single universally fixed Gregorian birth date for the 24 Tirthankaras. The birth dates (Janma Kalyanak) are given in Jain calendars and vary between traditions (Digambar vs Shvetambar) and regional calculations. Many sources treat these dates as traditional festival dates rather than fixed historical dates.

What I can offer you:

• Acknowledge that each Tirthankara has a Janma Kalyanak in the Jain Panchang, but the exact year/date depends on the Jain calendar system you follow.
• Some examples often cited in tradition (as part of Janma Kalyanaks) include:

- Parshvanath (23rd Tirthankara): birth year commonly given as part of traditional timelines around 872 BCE in many sources. - Mahavira (24th Tirthankara): birth year commonly given as around 599 BCE in traditional accounts. - Other Tirthankaras have their own Janma Kalyanak dates in the Jain calendars, but these differ by sect and calendar system.

If you want a detailed per-Tirthankara list with the Janma Kalyanak dates (according to Jain calendar traditions), I can provide that in the exact format used by Digambar and Shvetambar calculations.

You can read more about the Janma and other Kalyanaks for all Tirthankaras here