Protected tropical forest sees major bird declines over 40 years Apr 11, 2022 11:15 am by Lauren QuinnResearch Share on Facebook Tweet Email Images Deep in a Panamanian rain forest, bird populations have been quietly declining for 44 years. A new U of I-led study shows a whopping 70% of understory bird species declined 1977 and 2020. And most are down by half or more. Share on Facebook Tweet Email