Mexican jays are laying eggs 10 days earlier than in 1971. The earlier breeding coincides with a nearly 5°F (2.8°C) increase in average nighttime temperatures from 1971 to 1998.
Reference: Brown, J.L., S. Li, and N. Bhagabati, 1999. Long-term trend toward earlier breeding in an American bird: a response to global warming? Proceedings of the National Academy of Sciences, 96: 5565-5569.
