This 11 January 2018 from Canada says about itself:
11 January 2018
In part one of the process, join Dr. Ryan Norris and graduate students Alex Sutton and Koley Freeman, as they research the decline of Gray Jays in Algonquin Provincial Park in Ontario, Canada.
Each year, Norris and his team search the park to locate new Gray Jay nests to closely monitor reproduction success rates and continue to better understand reasoning for the Jay’s decline.
This research, started by Dan Strickland in the early 1970’s, has shown a 50% decline of this species in Algonquin and has suggested that warmer temperatures, attributed to climate change, are causing Gray Jays‘ critically important cached food to spoil.