Update August 18, 2003: added
two more (one an obvious juvenile) from today at the same location,
at the bottom of the page; based upon the appearance of the juvenile,
I think birds 2 - 4 must all be adults - ?
These Common Nighthawks Chordeiles
minor were photographed at the same rangeland location
near Fort Worth, Texas in 2003:
1) May 14. I would call this an adult male (date; size of primary
patch; white subterminal bar in tail.) Although warmer-toned on
the nape and scapulars than "typical" males, the structure
is almost standard, in that the long wings project obviously beyond
the tail-tip, and the size of the last visible primary space (actually
the P8-P9 gap) is large - at least as large as the preceding P7-P8
gap. One slightly odd feature is that P9 and P10 seem to be the
same length (I noted this same feature on another bird seen at
the same location.) I would have expected P10 to extend beyond
P9 by a visible amount; I wonder if wing structure varies among
populations (as opposed to randomly among individuals), and is
linked to migratory distance?:
The next three birds were on August 14, and were within 50
yards of each other (and in the exact location of the above May
bird):
2) I would call this an adult female (pattern of coverts and scapulars;
small primary patch not reaching P10; lack of white subterminal
tail band) - but I'd like to know if this is correct. A quite
warm-toned individual on which the tertials appear contrastingly
gray. The wings look oddly short, appearing to not reach the tail-tip,
plus the last visible primary space (P8-P9) gap) is short - a
little more than half the P7-P8 gap. As with the above May bird,
P9 and P10 seem to be the same length. The primaries look to be
in good condition - too good for an adult? I think that the well-marked
coverts/scaps indicate an adult, but maybe this is a juvenile?
3) I am a little perplexed by this one: there seems to be a white
subterminal band in the tail, indicating a male - yet there is
no sign of the white primary patch on the wing, and I'd have expected
an adult male to have the white on P10 visible, given the extent
of this feather in view. I am again assuming it is not a juvenile
because of the heavily-marked wing coverts, but perhaps this is
not a reliable aging criterion? The overall color of this bird
is more like a female/juvenile. As with bird 2) this individual
seems to have quite fresh primaries with P9 and P10 equi-distant
- but the P8-P9 gap looks to be more typical (longer than on bird
2)):
4) This individual was the most intriguing: It seemed to be quite
short-winged/long tailed, with the tail extending obviously beyond
the wing tips (I changed postion and confirmed it is not an artifact
of viewing-angle; the wing-tips are almost touching each other
rather than "crossed".) Also note the apparent molt
boundary in the primaries between P5 and P6; the inner two appear
round-tipped and fresh while the outer ones appear pointed and
worn. My understanding is that Common Nighthawk molts its primaries
on the winter grounds (Nov-March), while Lesser Nighthawk C.
acutipennis molts its primaries on the breeding grounds
in the summer (July-Sep.) Follow
this link to two pics of a Lesser Nighthawk from Nicaragua
(different subspecies?) in August; they seem to show the same
pattern in the primaries as does bird 4). The tail seems to suggest
it's not a male, and once more the well-marked scapulars and coverts
suggest to me it's not a juvenile (plus the worn-looking outer
primaries would not fit a juv.) The P8-P9 gap appears to be very
short - less than half the P7-P8 gap:
5) August 18, 2003: This and #6 were seen at dawn flying in to
roost in this tree, located just yards from the fenceposts pictured
above. Both birds had obvious Common Nighthawk-like white primary
patches visible in flight. This bird seems to be an adult female
(extensive black patterning in coverts; worn and rather pointed
primaries; lack of white in tail) and has P10 extending beyond
P9 - but a fairly short P9-P8 space. Note how strongly buffy the
underparts are, including the undertail coverts:
The pic below is from Aug 19:- same perch - different angle; the
white primary marks are visible here, showing that they are absent
from the outer three feathers:
6) August 18 2003: This clearly seems to be a juvenile (relatively
plain coverts with no black in the lesser and median coverts;
very fresh primaries with crisp buff edging). P10 extends slightly
beyond P9 and the P9-P8 space is quite long. Again this bird was
strongly buffy on the underparts, including the undertail coverts:
