Saturday, November 22, 2014

Where are all the migrating birds?

Ever since reading about fruit "strategies" in the Peterson Field Guide to Eastern Forests (John C. Kricher & Roger Tory Peterson, 1998), I have been preparing to watch for the coming of migrating birds.  I searched for the species that bear the fat-rich fruit they prize: flowering dogwood, Virginia creeper, spicebush, sassafras.   A casual census of the neighborhood revealed a pretty big population of flowering dogwood--a popular small, yard tree--if no other high-quality fruit-bearers.  Flowering dogwoods it is, then.  

I watched in anticipatory delight as a large crop of berries ripened to blood-red.  I and the neighborhood dogwoods all waited for the thrushes, catbirds and waxwings that--catching sight of the "foliar flags" of their bronze leaves--would descend on us in search of the high-fat fruit that would fuel their southward migration.  We waited some more.  By late October the bronze leaves--signals to birds-in-the-know that HERE they could eat their fill of the very best to be had--had almost all fallen.  The trees, still bearing laden platters, were forlornly waiting for guests who would never arrive.  One nearby tree in particular I looked in on often and hopefully, as it gradually lost berries, but then I discovered many of them in the grass beneath, untouched. 

 Spicebush (Lindera benzoin) is not found much nearer than the Blue Hill Reservation,
in Milton/Canton.  And it doesn't seem to be fruiting here this year.

Virginia creeper (Parthenocissus quinquefolia) is more common, but I haven't seen any with fruit.

Flowering dogwood (Cornus florida) was already turning on September 20th.

 Rich pickin's!  Come and get it!

All dressed up, and no one's coming.

From my journal of October 8th:

"Flowering dogwood in front of red house losing fruit, but a good deal of this is on the ground.  Another Cornus florida on corner of N Belcher has a lot of bare seeds on ground underneath--not exactly dispersal, but better than just falling off.  This same promised to show me one of the culprits: moving leaves & twigs and a harsh call sent me carefully adjusting my camera sight angles [in hope of catching sight of a migratory bird]--only to discover a squirrel calling for all the world like a blue jay.  (I even saw him move his head as he began each call.0   This went on for some time."

I don't think the problem is fruit scarcity, since I can't imagine there would be a much greater density of flowering dogwood in most forests.  My only hypothesis at the moment is that migrating birds simply avoid landing here in the city for any of a variety of reasons.  There may be more limitations to studying nature here than I'd imagined.  

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