302. Olive-sided Flycatcher

Up until a few years ago, we had always taken the presence of Olive-sided Flycatchers(Contopus cooperi ) here at Leaning Oaks as a given.  They reliably arrived the second week of May and lingered until mid September.  Their presence was usually announced by their strident piping calls, or their loud and often repeated "Quick! Three Beers" song.  In 2014 however, all of May passed without us hearing anything from an Olive-sided Flycatcher, nothing in the first week of June either.  Finally a single - and distant calling male on the 10th of June.
Olive-sided Flycatchers declines are widespread.  In 2008 the Committee on the Status of Endangered Widllife in Canada (COSEWIC) looked at Olive-sided Flycatcher and found that Breeding Bird Survey (BBS) data indicate significant and widespread declines in Olive-sided Flycatcher populations throughout North America.  Canadian populations experienced a 4.0% annual decline for the period 1968-2006, 3.3% annual decline for the period 1996-2006, total decline over that decade of 29%.
The cause of the decline is not clear.  Declines have been seen in many birds that make their living taking insects in flight including the Olive-sided Flycatcher.  Suggestions range from loss of wintering habitat, to shifts in timing of insect emergences, the use of pesticides and poor reproductive success in logged over habitats - but so far, the research hasn't been done to determine if it is one or more of these factors working in concert against the flycatchers. 
This year we do have a pair using the property once again and we have been hearing  "Quick! Three Beers" since the end of May.  We didn't take it for granted this year.