On November 21, 1993, (i.e. ten days later than
the latest record for Common Nighthawk in R & E) I saw a nighthawk fly
across I-435 near Worlds of Fun in Kansas City, Missouri. Entirely,
independently of me, Don Arni also reported seeing a nighthawk (perhaps the same
bird) at another Kansas City location on the same day. These records occurred
after publication of the Robbins & Easterla book. Both were fly bys, and
neither of us could rule out Lesser Nighthawk.
Indeed, the later it gets, the more likely it is
that a nighthawk in Missouri will be a Lesser Nighthawk. Common Nighthawks
winter in South America, whereas Lessers arrive earlier in spring and just
retreat southward in Mexico from the northern part of their range in winter.
Individual Lesser Nighthawks have been known to overwinter in the United
States. If the Southwestern subspecies of Cave Swallow regularly strays
northeastward as far as New England in November, why not also an occasional
I'll answer my own question. Lesser Nighthawk is
nearly impossible to separate from Common Nighthawk on the wing. If late
nighthawks are lessers, they are not making it into the record books because
nobody can identify them with sufficient certainty.
If I were on the MBRC, I would list any sight
record of a nighthawk after mid-October (perhaps earlier) as "Nighthawk