"You Might Be Getting Excited About Migration, But Not Me!"

“You might be getting excited about migration, but not me” might well express the sentiments of a pair of Red-tailed Hawks that I have been observing closely this year. For the past few years I have been following several pairs of Red-tailed Hawks breeding in the close suburbs of Boston. One pair has been followed year round, as this pair does not migrate. This March I started following another pair nesting on an exposed ledge in a suburban strip mall, and have been observing them and their fledged young very closely.

In late July I was surprised when early one morning we saw the adult male, known as Buzz, break off several tree branches and carry them to a large nest that the pair might have used in 2009, or rebuilt but did not use in 2010. (Data suggests the nest that they might have used in 2009 blew down in October of that year, but a completed nest was discovered in the same tree this March.) Buzz, the adult male, broke off at least three branches and carried them to the nest where they were worked into the foundation by his mate, Ruby. This was unexpected, and I haven’t found any references in the general literature to Red-tails refurbishing or maintaining empty, unused nests in July.

This behavior was reconfirmed a week later when we spotted Buzz breaking off branches and carrying them to the nest where they had raised three young this year. No one in a rather large corps of observers had seen either of the adults back in the nest since the last chick fledged in early June, but Buzz carried several green, leafy branches into the nest and did some point work on the entire nest. He did this under the watchful eye of an unidentified hawk that was occupying a “pillar perch” high on an apartment building overlooking all the territory that Buzz and Ruby had worked this year. Then Buzz and Ruby sat up on the end of the building, facing the unknown Red-tail for about an hour.

Later that same morning we saw both adults break off twigs and carry them into the top of a thick white pine tree, where their behavior suggests they had another, previously known, nest. That would mean they had been working on at least three, possibly four different nests in the month of July, little more than six weeks after their last chick had fledged.

Have readers observed or read about similar behavior in other Red-tailed Hawks? My expectation is that with a very dense population of breeding Red-tails in suburban Boston, this pair will probably not migrate, preferring to stay near their nests all year long. It looks like I will be much more interested in hawk migration this year than they will be.