California’s Birds Are Testing New Survival Tactics
The NY Times reports on a study comparing bird nesting behaviors of 202 bird species in the Sierra Nevada mountains today with what they did 100 years ago. They found:
Of 32,000 birds recorded in California mountain ranges in the old and new surveys — from thumb-sized Calliope hummingbirds to the spectacular pileated woodpecker — Dr. Tingley and his colleagues discovered that most species now nest about a week earlier than they did 70 to 100 years ago.
Ecologists generally believe that birds adapt to rising temperatures by moving to higher elevations or heading north. They shift their nesting time for a different reason: to sync with food availability, like an early appearance of plump caterpillars or swarms of insects.
The new study offers a plausible explanation. If the birds lay their eggs earlier, they can stay in their centuries-old range, with no need to migrate to higher altitudes.
View original post 19 more words