Fly Month

This morning, as I was conducting the sixth of the eight forest breeding bird census counts that I do each year in late spring and early summer, I noticed my first hoverflies of the year cruising a sunny patch of woodland understory.

Adult hoverflies are a bit intimidating because superficially they resemble wasps or bees.  While the larvae of most species are carnivorous, the adults are exclusively nectar feeders (hence the family's other common name: flowerfly [family Syrphidae]) so I have no reason to be anxious. 

As the forest birds settle into their territories, the forest quiets down quite a bit, providing me opportunities to observe other wildlife like the hoverflies.  This morning, there were four of the flies in the patch.  All were facing the same direction, and they all "hung" in the air, lined up side-by-side about eight inches apart, patrolling their own tiny patch of air space.  Occasionally, one would break ranks for a second, zooming away (usually backwards!) but returning almost instantly to take up exactly as it had left off.  Their world is unfathomable to me, but they are endlessly fascinating to watch.                                                                   

I refer to June as Fly Month. It's the month when mosquitoes make their first appearance and when deer flies are most maddeningly abundant.  Furthermore, I'm no fan of hot weather, so the addition of pestiferous flies to the mix only makes June all the more unpleasant.  Of course, the forest nesting birds will soon have plenty of new mouths to fill, so perhaps I shouldn't complain about the superabundant dipterans too much.

A Morning of Small Observations

I'm nearing the end of my annual series of censuses of the songbirds breeding in the deep woodlands of my preserve.  Using a protocol developed by the Laboratory of Ornithology at Cornell University, I spend three hours just after sunrise in the woods looking and listening for birds that have established territories.  I do this eight times each year, and have been doing it for 17 years now.  May's censuses are usually most interesting because the birds are active as they duke it out for the best nesting sites, but as the season progresses the territories are set and the woods become increasingly quiet.  The last two censuses are usually the least interesting.

This morning, the sun rising over a low ridge caught my attention.  There was a tree perfectly positioned between me and the low sun.  The tree diffused the light and illuminated the woods without blinding me--sort of a miniature solar eclipse.  The morning was calm; not a leaf rustled.  Nevertheless, there must have been an imperceptibly gentle north breeze perfusing the forest because, in the diffuse sunlight, I watched uncountable motes moving along through the air.  Some were animate, like insects and spiders, and a few insects flew counter to the tide, but generally a seemingly endless drift of dust, pollen, seeds and who knows what else wafted along through the forest with the current.  To be honest, my first thought was, "I'm breathing this!"  My second thought was, "This is a perfect example of what I tell my restoration ecology students about woodlands receiving allochtononous inputs from the surrounding countryside."  But, in the end, I mostly just marveled at the show.

Further along, I came upon a tiny opening in the forest patrolled by three hoverflies (Family Syrphidae).  Hoverflies are always a welcome bonus on bird census days, especially on slow, late-season days, because they can be endlessly fascinating--and distracting.  For the most part, the flies maintain their relative and absolute positions, getting out of formation only to make darting forays in pursuit of aerial prey and then returning to exactly the same spot.  Today, for the first time, with the woods so still, I noticed that the hoverflies' wings generated enough of an air current to cause the leaves of the spicebush shrub above which they were located to flutter.  Amazing.