Expert: Roger Lederer - 8/16/2008

Question
I am located in central Michigan, rural location, large backyard grass lawn with adjoining hardwoods. This year was a typical year... we had 3 Robin nests on our property; I believe most reared several broods; so many Robins in the yard was a common occurrence.  Last several years, the Robins are gone by August... NONE...  to my best recollection... they used to stay around until mid-late fall.  I have discussed this with friends & neighbors, who have observed the same thing... last couple years the summer weather has been exceptionally nice, so I can't see that a factor.  WHY are the Robins leaving in mid-summer..??

Answer
Well, there could be several factors but I can't say which for sure. Most likely, climate change (global warming) has a lot to do with it. Although birds do react to the weather somewhat, they migrate mostly due to day length. But flowers and worms and insects, etc. react to the temperature and they come out early. Thus the flowers and invertebrates produce seeds, fruit, young bugs, etc. earlier and thus their life cycles end earlier in the year. So food for the robins runs out earlier than it used to and they leave. That's a likely explanation, I think.