Scott and all:
        Some reflections on the common nighthawk, a perpetually fascinating
bird. Because of its habits, its movements are not so well known as
those of other birds. There's a web site URL below for a project that
collects counts of these birds, mostly as fall migrants seen at dusk.
        As for spring migrants, my limited experience is they pass over
beginning as early as mid-April (the earliest Franklin Co record is
4/19), with most coming between early and mid-May. At this time, the few
I've seen have been in small groups, up to a dozen, flying way up, easy
to miss--as I'm sure I have--by day. During the nesting season, they
seem to be most active crepuscularly, with birds seen in the middle of
the night much less often. Nighthawks have great vision, but without
full moonlight or artificial lights they are less likely to be
successful catching insects by night, and some studies have shown they
are far less active ~10 pm-2 am.
        Project Nighthawk, cited below, has numbers that show over 90% of the
nighthawks counted migrated between August 17th and Sept 5th. Local
records here include 3000+ on 9/3/1976 and ~2500 on the same date in
1992. I've seen 600+ here, on 9/9/1994. This is not the whole picture,
however; here we have a record of 224 on 10/3/2006, a bird that flew
into the OSU Main Library on 10/22/1965, and a straggler as late as
11/20/1975 (one is tempted to wonder if a *lesser nighthawk* of the west
might be involved here, but who knows?  Ohio has no record, but West
Virginia's first record of lesser nighthawk was documented by a prisoner
in the state penitentiary 4/28/2004). Good fall numbers seem to be
associated with major rivercourses running north and south.
        In the fall, it seems they gather in flocks to migrate, moving in late
afternoon through dark; this is when even the most casual observer
notices them. I recall reading somewhere of a Canadian flock of ~16,000
at this time. Maybe these low-altitude swarming flocks, their timing
suggested to coincide with peak presences of insects such as flying ants
most often occurring along riparian corridors with wet meadows that
concentrate insects at this time, roost in loose communities, which
might explain why the flocks often turn around and hook back north just
before dark: they do not know what lies ahead, but perhaps take note of
good roosts not far behind on their route.
        I haven't heard any really good evidence that nighthawks *don't*
migrate during the darkest hours. Maybe someone has used technology to
find out? Nor do I know much about what they do in the morning as they
continue migration, except that they don't gather in great numbers at
low altitudes. All the dawn birds I see in fall are in very scattered
small numbers; if you see a thousand birds one evening, why don't you
see as many the next morning? Maybe they all quickly ascend to high
altitudes to resume migration in scattered groups. Maybe, like swallows,
they burrow into mud to spend the winter. It would be great to hear from
anyone with information on any of these questions.
Bill Whan
Columbus


gravel roof patches--a way to attract nesting nighthawks:
http://nhbirdrecords.org/bird-conservation/library/Nighthawk-handbook.pdf

project nighthawk:
http://mysite.verizon.net/risinger2/index.html



Scott Albaugh wrote:
> I have been conducting home-made Common Nighthawk surveys in my Belmont
> County yard for two consecutive years.  Tonight was the best night yet with
> the largest flocks that I've seen.  Prior to this evening the highest number
> of birds in any one flock was 26.  Mostly I would see singles and doubles
> flying relatively low over the ground.  The birds travel in all directions
> with a near majority curiously heading north.
>
> This evening, for the first time, I saw large swirling flocks at much higher
> altitudes than birds seen previously.  There were two south bound flocks;
> one of 30 and the other of 40 (estimate.)  I also saw two flocks that
> appeared to be north bound; one of 22 and one of 61.
>
> This whole nighthawks flying north thing has me quite confused.  When they
> were singles and doubles flying low, I just thought maybe they were staging
> somewhere and would fly south in a few days with a large group.  But tonight
> I saw two groups very high in the sky disappear to the north.  Confusing...
>
> Counting the usual singles and doubles flying low, I ended up with 160
> birds.  That is nearly 40 more than I had in the complete 12 hours of
> surveying last year.
>
> I intend to write up the results of my home-made surveys and I will share
> them with the group.  Stay tuned...
>
> Scott Albaugh
> Belmont County

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