Location Code: WAY22
Rufous Hummingbird (Selasphorus rufus), immature female
November 7, 2011. First
observed by homeowner (Mark Wloch) in early afternoon on 7 November
2011, and last observed on 14 November 2011. Photos sent to me by Wloch
on 7 November 2011 were indicative of a Rufous or Allenís Hummingbird
as they showed a bird with pale rufous flanks and conspicuous rufous in
the tail feathers. Since the site was only 15 miles from my home (Iím
used to going 100-200 miles!), I arrived at the home at 3:30 p.m. that
day, set up my trap at 3:40 p.m., and caught the bird at 3:46 p.m.
The bird was banded and released at 4:00 p.m. under Federal Bird
Banding Permit No. 23156, and Michigan Scientific Collectors Permit No.
At the home of Mark Wloch in
All data and observations in this report were made by Allen
Chartier. Also present was the homeowner (Mark Wloch) and Jerry Jourdan.
Photographed in-hand with digital camera (photos attached to this
document). All measurements
were made using digital calipers. Bill
corrugations were determined by viewing through a 10x loupe, as they are
impossible to accurately determine any other way.
conditions: The sky was overcast
and the temperature was 61 degrees. The bird was banded, weighed, and
The bird was first observed when captured for banding, so only
in-hand data is provided here. It was aged, sexed, and identified in
that order. The proper use
of Stiles (1972) for banders requires that an individual Rufous/Allenís
Hummingbird in-hand be correctly aged and sexed before a species
determination can be made (B. Sargent and N. Newfield, pers. comm.).
The bird was aged as hatch-year (immature) based on the presence
of shallow groovings or corrugations on about 90% of the upper mandible.
This is universally recognized as the most reliable method for age
determination in hummingbirds (Ortiz-Crespo, 1972).
The upper tail coverts and rump were entirely green. The rufous
on the base of the one central rectrix (r1) was restricted to about the
basal 25%, and was completely covered by the green upper tail coverts.
These characters suggested this bird was a female. The wing measurement
of 44.08 mm was longer than any age of male Rufous or Allenís given in
Stiles (1972), so this measurement is a very strong indication that the
bird was female. The bill measurement (exposed culmen) can sometimes be
helpful for determining sex. This birdís bill appeared to have a
deformity on the inside tip somewhat similar to avian pox, so might have
been a temporary condition. This did not affect the exposed culmen
measurement, which was 18.08 mm; longer than adult and immature males of
nominate (S. s. sasin)
Allenís Hummingbird, but within range of immature males of the sedentarius
subspecies* of Allenís and shorter than the range of adult females of sedentarius.
So, the bill measurement somewhat supports the sex as female. The
pattern of iridescent gorget feathers on the throat can sometimes be
helpful in determining the sex of Selasphorus
hummingbirds. This bird did not have any on the throat (see photos),
which is infrequent but can be shown by immature males and females of
either species, so is somewhat useful for supporting an age
determination but not the sex.
Given that the bird was a hatch-year (immature) female, using
Stiles (1972) we can determine whether this bird was a Rufous or
Allenís Hummingbird using several additional measurements and
observations. The presence
of notching and/or emargination on the second rectrix from the center
(r2) is one feature that can often be observed in the field to confirm
Rufous. The r2ís of this
individual had no emargination and no notching (see photos), not
allowing confirmation of Rufous. Using Figure 3 in Stiles (1972), the
shape most closely matched figure Ca for Rufous, though it also matched
other figures for Allenís, which is why measurements of the widths of
two other rectrices is critical; the central rectrix (r1) and the
outermost rectrix (r5) are the primary means to confirm identification.
One central tail feather (r1) was measured as 8.27 mm. This is around
the mid-range for immature female Rufous (7.8-9.5 mm) given in Stiles
(1972), and very slightly above the upper end of the range for immature
female of nominate (S. s. sasin)
Allenís (6.9-8.2 mm). But it is also near the upper end of the range
for immature females of the sedentarius
subspecies of Allenís (7.3-8.4 mm). So, the width of the central
rectrix provides strong but not entirely conclusive support to the
identification as Rufous Hummingbird. One outer rectrix (r5) was
measured as 4.34 mm. This is above the mid-range for immature female
Rufous (3.2-4.7 mm) given in Stiles (1972), and is significantly broader
than the maximum range for immature female Allenís for both subspecies
(max. 3.3 mm), and so provides conclusive and diagnostic support to the
identification as Rufous.
measurements are often not very useful.
This birdís tail measurement of 26.0 mm is above the maximum
for immature females of the nominate subspecies of Allenís (Stiles
gives no corresponding measurement for immature female S. s. sedentarius), and near the mid-range given for Rufous. So tail
length is also useful in this case.
the wing measurement of 44.08 mm is above the maximum for immature
females of nominate Allenís, but is within range though near he upper
extreme for immature females of the sedentarius
subspecies of Allenís (42.1-45.0 mm). So wing length also somewhat
supports the identification as Rufous Hummingbird.
There was extensive body molt evident on this bird.
All primaries were old and worn. On the tail, r3 and r4 appeared
The bird had a fat code of 0 (0-3 scale) and weighed 3.30 grams, a bit
below average for an immature female at this time of year.
Allenís Hummingbird is the species most similar to Rufous
Hummingbird. On this bird, the lack of emargination or notching on the
second rectrix did not allow identification as Rufous, requiring
measurement of tail feathers. The widths of the central (r1) rectrices
provided strong support and the widths of the outer (r5) rectrices
provided diagnostic and conclusive support for the identification as
Rufous. Both wing and tail measurements also provided additional support
for the identification.
I have seen hundreds of Rufous
Hummingbirds in several states, banded nearly 60 in Michigan, Ohio,
Indiana, and Ontario, and handled ~35 in Louisiana in February 2003 with
Nancy Newfield, and handled about a dozen in Arizona in July 2006
helping other banders. I
have seen several Allenís Hummingbirds on two trips to
report was written:
This report was written on December 14, 2011 based on data and
photos taken during the banding process.
None were consulted while observing the bird in the field, nor
were any used to write notes in the field or to write this report.
Stiles (1972) and Pyle (1997) were available during the banding
of the bird.
*There are two subspecies
of Allen's Hummingbird. One
is the widespread and migratory nominate subspecies (Selasphorus
sasin sasin) breeding from coastal northern
A new method to separate immature and adult hummingbirds. Auk
Identification Guide to
North American Birds: Part 1. Slate
Creek Press, CA.
1Stiles, F.G., 1972. Age
and Sex Determination in Rufous and Allen Hummingbirds.
The Condor 74: 25-32.