A neighbor was recently surprised to see Robins in Oak Park in the middle of winter. I also saw three Robins a few weeks ago at Ream Park playground, and then Ethan reported them a week ago at Julian Middle School. So, what’s up? Most people consider Robins to be a sign of spring, but maybe they’re not.
First, it would be nice to confirm our isolated observations — what if we’re not getting the whole picture? Ethan is working on a science fair project about bird migration in spring, and he extracted some data from the FeederWatch website that shows an interesting pattern. The following chart shows the percentages of Illinois FeederWatch sites reporting American Robins through the 2007-2008 season. (More than 200 sites reported bird data that winter — including ours!)
|Nov 10-||Nov 24-||Dec 08-||Dec 22-||Jan 05-||Jan 19-||Feb 02-||Feb 16-||Mar 01-||Mar 15-|
To us, this shows two things: (1) A small number of Robins really do stick around people’s yards all winter, but (2) there is a huge influx of Robins through the month of March. So, maybe seeing Robins in just a few yards does not mean that winter’s over. However, seeing Robins in lots of people’s yards is a sign that spring is on the way.
Nature Note added 2:40 p.m. on Friday, February 6:
The e-mail birding lists for Indiana and Illinois recently had interesting discussions about this issue. If you want to read more about it, go to the public archives of the Indiana Birding list. One post asks some questions, and another provides some good answers. (The last two links go take you directly to the individual e-mails in the public archives for the Indiana list.)
The discussion on the IBET Illinois Birding discussion list went into detail about why Robins may be wintering in Illinois more often than in the past. Some writers speculated about possible effects of global warming. However, others mentioned the role of increased winter food supply due to human planting of fruit-bearing ornamental trees, like crab apple, and the spread of invasive shrubs, like Buckthorn. Unfortunately, to read this thread you must join IBET and then search their members-only archives. The tread began February 3rd, and it’s under various subject lines, all including the name, “Robin.”
Dad philosophized a bit more about signs of spring on February 9, 2009.
We heard the first Robin sing near our home on March 3, 2009.