Or their homes are being rented out to STRs.

Monarch butterflies are quite a sight to see, arriving mid-October and staying in the area through the end of February.
But, these butterflies are starting to dwindle.
“Ever since we began monitoring monarch butterflies — since the 1990s — what we have seen is a steep decrease in their population, an over 95% drop,” said Natalie Johnson, who works at the Pacific Grove Museum of Natural History.
What’s causing the drop in these species? There are a few factors…
“One of the reasons is habitat loss,” said Johnson. “Another is pesticides, and clime change.”