Complex sentence: The birds appear to have been freshly killed or stunned, and were drawn by the Dutch artist Joris Joostensz Laerleon on Mauritius, but they were not published until 1969.
Split into simpler sentences: The birds appear to have been freshly killed or stunned. The drawings were made by the Dutch artist Joris Joostensz Laerleon on Mauritius, but were not published until 1969.