Monday, September 24, 2012

Fall Activity

September has seen a fair amount of activity at the nest ledge!  Especially in the last week, both birds have been in the nestbox at least once a day, checking things out and otherwise strengthening their bond.  Here's a video from today. 

What's with the increase in sightings all of a sudden?  Simply put, the length of day during this time of September is similar to that in March (about 12 hours from sunrise to set) when the falcons are gearing up for nesting season.  The hours of daylight trigger hormones to reinforce their bond to the site and to each other. 

It won't develop into anything at this time of year though because, in contrast to the spring when days continue to get longer and fuel the behavior, now the days are getting shorter.  So we'll only see this behavior for a short time.  In similar fashion, I heard a chorus frog calling over the weekend-a species that calls and breeds in March then goes quiet for the rest of the season.  Until the length of the days in September stir them up briefly again.