Here are Bruce Peterjohn's notes about the hummingbird.
Identification of the Green Spring GardensPark Rufous Hummingbird
Theextensive rufous at the base of the tail indicated that it was a
hummingbirdof the genus Selasphorus. Calliope hummingbird was eliminated bythe
more extensive rufous in the base of the tail on this bird, its overalllarger
size (especially bill and wing length), and the shape of its centraltail
feathers (distinctly wedge-shaped in Calliope but not on this
bird).Broad-tailed Hummingbird is a larger bird than Rufous/Allen's and the
measurementsof the bill, wing, and tail were all too short for a Broad-tailed
(forexample, the tail was only 25 mm long while most Broad-taileds have
tailsgreater than 30 mm long).
Thefinal identification challenge was the separation of Rufous from
Allen'shummingbirds. First, we have to determine the age and gender of the
bird.This bird was sexed as a female based on the extensive green base to
thecentral tail feathers (males have an extensive rufous base to these
feathers).She was aged as a hatch-year bird based on the presence of grooving
onher mandible (a feature found on hatch-year birds but is lost during
theirfirst year so that these grooves are not normally present on adult
birds).Establishing that the bird was a hatch-year female allowed us to use
severalmeasurements to establish this identification. Allen's is overall a
slightlysmaller bird than Rufous, size differences that are not evident in
thefield but can be confirmed in the hand. All of the dimensions of this
birdwere well within normal for a Rufous but were either at the extreme endor
entirely too large for an Allen's. For example, the wing length wasgreater than
44 mm while hatch-year female Allen's have wing lengths lessthan 43 mm (and
normally around 40 mm). The outermost tail feather wasalso relatively wide at
4.7 mm, while the width of this feather on hatch-yearfemale Allen's is 3.3 mm
or less. Given that all of the measurements stronglysupported the
identification of a Rufous Hummingbird, I did not feel theneed to collect any
feathers for documentation purposes (and I am not surethat the permit issued by
the park would have allowed me to collect feathers).
Thesecond tail feather lacked any apparent emarginations on this bird,
whichfrom my experience occurs very frequently on hatch-year female Rufous
Hummingbirdsas well as on Allen's Hummingbirds. When this feather is distinctly
emarginated,then that feature is distinctive for a Rufous. However, many Rufous
lackthese emarginations while some Allen's can have slightly emarginated
feathers,so use of this feature requires some experience with both species to
understandthe range in variation found in both. Based on our study of birds in
thehand with proven identifications, the color of the feathers around theeye is
not a reliable field mark and should not be used in the separationof these
species.
Bruce Peterjohn
Laurel, MD
